Hi Flying Bird,

one aspect that may help to find a decision wether to use one or two motors
might be the fact that, the more power you want- or have to- apply, the more
advantageous it is to have the thrust acting as close the the center of drag as
possible. Thus, undesited secondary effects like pitching up when applying power
can be reduced. Using a single motor, this could be achieved by installing it at
the aft end of the envelope, necessitating a counterweight at the nose- the
battery. That means, very long (and weighty) powerlines will be necessary. On
the other hand a great adventage of this arrangement is that the prop could be
placed ahead of the control surfaces. Thus, the ship keeps controllable at
pretty low speeds, if only the motor is running to blow  over the control
surfaces.
With two motors, paced amidship at the sides of the envelope, the resulting
thrustline can be brought close to the center of drag, too. The battery then
could stay in the gondola and the powerlines were short, but controllability
wold decrease with the airspeed, no matter if the motors are running or not.
The overall mass generally rises or falls with the installed power. There
shouldn't be much difference between a single big engine or two smaller motors,
als long as the overall power is about the same. The battery, being the major
factor for the mass of the drive, stays the same, anyway.

Greetings
Luftschipper


--- In rc_airship_regatta@yahoogroups.com, Flying Bird <flyingkalubird@...>
wrote:
>
> Hello Luftschipper,
>
> Thanks for the guidance again. Could you pls tell me whether I should go for
single motor or with two motors? Your point is valid for the case, the yaw force
will not be good enough unless the levers are long. From everyone's suggestions
I think having a rudder and elevator will be the best bet. And about the weight
and other calculations I will only be able to make any decision unless i decide
the number of motors which I will be using. I was thinking of using two motors
for the only reason that I could use it for differential thrust vectoring! If
one motor can handle it well then I will go for single motor itself. What do you
suggest?
>
> Regards,
> Flying Bird.
>
>
>
>
>
> --- On Thu, 10/15/09, luftschipper <phanick@...> wrote:
>
> From: luftschipper <phanick@...>
> Subject: [rc_airship_regatta] Re: Procedure of airship design.
> To: rc_airship_regatta@yahoogroups.com
> Date: Thursday, October 15, 2009, 11:39 AM
>
>
>
>
>
>
>  
>
>
>
>
>
>                   Hi Flying Bird,
>
>
>
> for an outdoor design, I feel that for sufficient pitch control a elevator is
mandatory. Vertical thrust works fine in calm indoor conditions, but outside
there will always be some wind, turbulence, updrafts, downwash and so on. Even
if you feel it was calm, by flying an RC airship you will learn that there is
more motion in the air then you thought. After all, it is an airSHIP, and like
any ship it is carried away by the currents of the see it is swimming in. Be
aware, that your ship will NOT stand still, as long as you do noting at the
controls. The opposite is true: to make it stand on one point, you have to work
hard at the contols. Well, you will see...
>
>
>
> To cope with these currents, you need a control system which produces a quick
and strong reaction. A simple aerodynamic rudder/elevator control does provide
this, AS LONG AS YOU FLY FAST ENOUGH, what means, that you need need a
sufficiently powerful motor. Being to slow when flying outside will make your
airship a toy of the wind anyway, even if you install vectored thrust control.
No motor will be able to counteract the effect of even a slight gust hitting the
envelope laterally. The force of the air, pressing laterally (or vertically) on
the huge sail area of the envelope is stronger than any motor of reasonable
size. Thus i feel that tilting the motors is a nice gadget, but for an
outdoorship I think it won't really pay off. (And on an indoor ship I prefer to
have a separate vertical thruster which can be used comletely independent of the
horizontal motors.)
>
>
>
> Due to the enormous aerodynamic yaw dampening of the long envelope, controling
the vertical axis by differential thrust will have little effect as long as the
lever from the CG to the thrustline is short compared to the length of the ship,
which it usually is.
>
>
>
> Greetings
>
> Luftschipper
>
>
>
> --- In rc_airship_regatta@ yahoogroups. com, Flying Bird <flyingkalubird@ ...>
wrote:
>
> >
>
> > Hey luftschipper,
>
> > Â
>
> > Such a lively reply  thank you for
>
> > the reply.
>
> > Â
>
> > As you have rightly pointed out, I was also looking for the step by step
>
> > procedure which you have told. There is no indoor facility available for me
>
> > here so I
>
> > will be going for outdoor design only. And thanks for putting light on
result
>
> > prospectives, i will keep that in my mind.
>
> > For the controls, I am planning to go a rudder (Yaw) and a fixed fin for
vertical stabilizing. For Pitch I will tilt the motors (Planning to use two
motors). Will that system do for the airship? And what if we run motors at
different speeds  and we will get yaw motion , Isn't it (Control will be
little difficult though)? I will find the electronic components available and 
will follow the procedure you have told me.
>
> >
>
> > Thanks again,Flying Bird.
>
> >
>
> >
>
> > --- On Thu, 10/15/09, luftschipper <phanick@ > wrote:
>
> >
>
> > From: luftschipper <phanick@ >
>
> > Subject: [rc_airship_ regatta] Re: Procedure of airship design.
>
> > To: rc_airship_regatta@ yahoogroups. com
>
> > Date: Thursday, October 15, 2009, 6:37 AM
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > Â
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >                   Hello Flying Bird,
>
> >
>
> >
>
> >
>
> > from your postings requesting a 'design pocedure' I conclude that this will
be your very first airship, right? Up till now this thread was focussed pretty
much on the shape and the design of the envelope. This is indeed an important
subject in airship design, never the less I feel like for a beginner in this
trade there are some other things to be considered beforehand.
>
> >
>
> >
>
> >
>
> > The very first point is: what is the intended pupose of your project? Of
course you will answer something like: It is meant to be the perfect RC-airship
:-). I hope I won't toss you out of this dream too violently when I tell you
that in this case you will fall short of expectations. Most of the people in the
scene will remember their first ship as one that was not very perfect, but one
that helped them to gather a lot of experience.
>
> >
>
> >
>
> >
>
> > I'ld suggest to keep this in mind and to choose a kind of airship well
suited for this purpose. That means for example to build an indoor instead an
outdoor airship, for inflating, rigging, trimming and all the things that have
to be done before flying can begin is much easier to do in a sheltered area.
Moreover you don't have to wait for suitable weather conditions to perform the
next test flight.
>
> >
>
> >
>
> >
>
> > Then you have to decide which kind of control principle you want to use.
control surfaces at the empennage, or control by thrust modulation, or both? how
many motors? motors tilting or rigidly mounted? How much power is necessary?
(Much less on an indoor than on an outdoor ship) From these decisions you have
to derive the necessary components to find out how heavy your equipment and
where the centeres of gravity of the components will be. Together with the
estimations of the masses ot the gondola, empannage, wiring etc. you can find
out how much lift the envelope has to provide.
>
> >
>
> >
>
> >
>
> > Only now it is time to begin the layout of the envelope: how much volume,
how much surface, specific mass of the material, weight of the envelope.. Enough
lift left? No? One more time...
>
> >
>
> >
>
> >
>
> > Oh, not to forget: don't lay out your envelope too tight, I'ld recommend a
surplus lift of at least some 25%. Think that is too much? As a rule, things
become heavier during construction all by them selves. And you will need some
ballast anyway to trim the ship. And, depending on the tightness and the
permeability of your envelope, helium will get out of the envelope and air will
get in, at least if it's inflated over a longer period of time.. Even if you
refill it, the quantity of air diluting the helium will reduce the lift. Having
enough margin enables you to compensate this loss by removing ballast. If you
haven't, your ship may keep stuck to mother earth unless you deflate the
envelope completly and fill it again with new helium. Cumbersome and expensive
game.
>
> >
>
> >
>
> >
>
> > I hope, these lines will help you to build a successful RC airship as much
as Johanne's explanations did before.
>
> >
>
> >
>
> >
>
> > Good luck and up ship!
>
> >
>
> > Luftschipper
>
> >
>
> >
>
> >
>
> > --- In rc_airship_regatta@ yahoogroups. com, Flying Bird <flyingkalubird@
...> wrote:
>
> >
>
> > >
>
> >
>
> > > Thanks Johannes once again,
>
> >
>
> > >
>
> >
>
> > > Now almost everything is clear to me. I will work out with this design
problem and quickly start the construction work. I will be using PVC sheets for
the envelope and will seal them using Acetone, I have tried once It works fine,
but don't know whether PVC will be able to take the load or not, anyways that
can be concluded only after realizing it.
>
> >
>
> > > I will come back if there are any other Non-Stupid questions
>
> >
>
> > >
>
> >
>
> > > I have noticed most of the people in this group are from Germany!
>
> >
>
> > >
>
> >
>
> > > Ich lerne Deutsch, ich weiss (I don't know how to type scharfes S) und Ich
spreche etwas Deutsch.
>
> >
>
> > >
>
> >
>
> > >  Danke Schoen,
>
> >
>
> > >
>
> >
>
> > > Flying bird.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > --- On Tue, 10/13/09, Hannes <johannes.eissing@ ...> wrote:
>
> >
>
> > >
>
> >
>
> > > From: Hannes <johannes.eissing@ ...>
>
> >
>
> > > Subject: [rc_airship_ regatta] Re: Procedure of airship design.
>
> >
>
> > > To: rc_airship_regatta@ yahoogroups. com
>
> >
>
> > > Date: Tuesday, October 13, 2009, 9:23 PM
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Â
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Hi Flying bird,
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > you're welcome. Find here a basic helpfile for the Series58 Generator:
>
> >
>
> > >
>
> >
>
> > > http://www.airshipw orld.info/ software/ 2009/08/generato r-v06-available/
comment-page- 1/#comment- 3262
>
> >
>
> > >
>
> >
>
> > > (beware of line breaks within the link)
>
> >
>
> > >
>
> >
>
> > > (heck, I'll attach it below!)
>
> >
>
> > >
>
> >
>
> > > It addresses most of your questions, including proposed values for the
parameters.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > The points generated are pairs of x/y point coordinates. If you try to
plot those in EXCEL or openoffice calc, you must choose "x y plot" as graph
type. In a standard plot type, you will ge one curve of x- ordinates and one
curve of y-absissae, looks weired indeed. In other words, the 1st column of
numbers exported to the clipboard are x- values (lengthwise) , the 2nd column
are the corresponding radii of the body of revolution.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > A saying is "there are no stupid questions, there are stupid answers". Too
often I do forget the world is full on non-flight-physics- engineers, sorry for
this ;o)
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Best, Johannes
>
> >
>
> > >
>
> >
>
> > > PS.: keep us posted about your project, and keep asking questions!
>
> >
>
> > >
>
> >
>
> > > PPS.: A teacher of mine used to say "keep wondering"
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Appendix: Basic Series58 Generator Help file
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Airshipworld Gertler Series 58 Generator â€" Version 0.6
(27.03.2009)
>
> >
>
> > >
>
> >
>
> > > (c) A. Grunewald & J. Eissing
>
> >
>
> > >
>
> >
>
> > > http://www.airshipw orld.info/ software
>
> >
>
> > >
>
> >
>
> > > Helpfile by Johannes EiÃÆ'Ÿing, 18.08.2009
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > General
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > The Series 58 hullforms were developed by Morton Gertler and Louis
Landweber for the David Taylor Model Basin DTMB in 1950 [1], [2]. These shapes
are described by five parameters such as slenderness ratio, prismatic
coefficient, location of maximum thickness, bow- and sternradius. The series 58
shapes are well covered in literature because of their parametrics and
reproducibility. Their value for research and development is comparable to the
well known NACA four- and five digit profiles.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > User Interface
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - Render Profile
>
> >
>
> > >
>
> >
>
> > > pretty much self explaining, klicking this button updates the plot window.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - Copy Values to Clipbord with TAB/semicolon
>
> >
>
> > >
>
> >
>
> > > Points shown in the plot window are copied th the clipbord as x/y point
coordinates. Only the coordinates for the upper shape are exported to the
clipbord. The number of Points "n" is set in the dialogue box "Input
Parameters", see below. Coordinates are given nondimensionally, referred to the
length of the body. Points are allocated in a full cosine distribution. The
delimiting character can be chosen as TAB or semicolon. Chosing the TAB
Character facilitates import to e.g. EXCEL by CNTRL+V
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - Calculated Parameters:
>
> >
>
> > >
>
> >
>
> > > - Cs
>
> >
>
> > >
>
> >
>
> > > Surface Coefficient as introduced by Gertler [1]
>
> >
>
> > >
>
> >
>
> > > Cs = Swet/(L*pi*D) where
>
> >
>
> > >
>
> >
>
> > > Swet = wetted surface area,
>
> >
>
> > >
>
> >
>
> > > L = Length of the body
>
> >
>
> > >
>
> >
>
> > > pi is the ratio of perimeter to diameter of a circle with approximately
3.1416
>
> >
>
> > >
>
> >
>
> > > D is the diameter of the body.
>
> >
>
> > >
>
> >
>
> > > Reversely, wetted surface area is computed by
>
> >
>
> > >
>
> >
>
> > > Swet = Cs*L*pi*D
>
> >
>
> > >
>
> >
>
> > > Cs is calculated numerically, meaning it's accuracy increases with the
>
> >
>
> > >
>
> >
>
> > > number of points n (see Input Parameters). Already with 20 points the
>
> >
>
> > >
>
> >
>
> > > error is less than 0.5%, with 50 points about 0.05%.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - CB
>
> >
>
> > >
>
> >
>
> > > Centre of buoyancy. This is the volumetric center of the body referred to
the body's length.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - a1 to a6
>
> >
>
> > >
>
> >
>
> > > are the computed polynomial coefficients for the shape function
>
> >
>
> > >
>
> >
>
> > > y(x)=D*sqrt( a1*(x/L)+ a2*(x/L)^ 2+a3*(x/L) ^3+a4*(x/ L)^4+a5*( x/L)^5+a6*
(x/L)^6)
>
> >
>
> > >
>
> >
>
> > > where
>
> >
>
> > >
>
> >
>
> > > y(x) is the local radius (ordinate)
>
> >
>
> > >
>
> >
>
> > > x is the abscissa
>
> >
>
> > >
>
> >
>
> > > D is the maximum diameter
>
> >
>
> > >
>
> >
>
> > > L is the length of the body.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - Input Parameters
>
> >
>
> > >
>
> >
>
> > > - n â€" Number of steps
>
> >
>
> > >
>
> >
>
> > > Here, the number of points to be computed for the shape can be set. For
standard use, 20 to 50 points will do.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - m â€" Point of maximum thickness
>
> >
>
> > >
>
> >
>
> > > This is the position of the maximum section, referred to body length.. A
typical value is 0.40.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - r0 â€" Dimensionless bow radius
>
> >
>
> > >
>
> >
>
> > > Bow and stern radii are nondimensionalized by the following relationship:
>
> >
>
> > >
>
> >
>
> > > r = R*L/D^2=(R/D) *(L/D) where
>
> >
>
> > >
>
> >
>
> > > r is the nondimensional radius
>
> >
>
> > >
>
> >
>
> > > R is the dimensional radius
>
> >
>
> > >
>
> >
>
> > > L is the Length and
>
> >
>
> > >
>
> >
>
> > > D is the diameter of the body.
>
> >
>
> > >
>
> >
>
> > > A typical value for the bow radius is 0.5, being the bow radius of any
prolate spheroid. A pointed bow would show a value of 0.0.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - rl â€" Dimensionless stern radius
>
> >
>
> > >
>
> >
>
> > > See above r0. A typical value for a tail radius is 0.1. A pointed tail
would show a value of 0.0.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - Cp â€" Prismatic coefficient
>
> >
>
> > >
>
> >
>
> > > The overall prismatic coefficient is a measure of how good a slender body
fits an enveloping prism, built from the maximum crossection extruded for the
length of the body. In case of a body of revolution, this prism is a cylinder.
An arbitrary ellipsoid shows a prismatic coefficient of 2/3. Typical values for
airships and submersibles are in the range of 0.60 to 0.70.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > - L2D -Length to Diameter ratio
>
> >
>
> > >
>
> >
>
> > > This is the slenderness ratio of the body, typical values being in the
range between four and ten. A typical value for airships is five.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > References
>
> >
>
> > >
>
> >
>
> > > [1] "Resistance Experiments on a Systematic Series of Streamlined Bodies
of Revolution â€" For Application to the Design of High-Speed
Submarines"
>
> >
>
> > >
>
> >
>
> > > DAVID TAYLOR MODEL BASIN WASHINGTON DC
>
> >
>
> > >
>
> >
>
> > > Gertler, Morton, APR 1950
>
> >
>
> > >
>
> >
>
> > > [2] "Mathematical Formulation of Bodies of Revolution"
>
> >
>
> > >
>
> >
>
> > > DAVID TAYLOR MODEL BASIN WASHINGTON DC
>
> >
>
> > >
>
> >
>
> > > Landweber,L. ; Gertler,M., SEP 1950
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > --- In rc_airship_regatta@ yahoogroups. com, "Flying" <flyingkalubird@
...> wrote:
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > Hello Johannes,
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > Thank you so much for the kind reply.
>
> >
>
> > >
>
> >
>
> > > > Could you please tell me something about Series58 Shape Generator?
>
> >
>
> > >
>
> >
>
> > > > What is prismatic coefficient? Rest of the input parameters I know but
what are the optimal values of these inputs for my requirement, that how will I
know?(I know its a stupid question but I really don't know)  How does each
parameter affect the performance of the airship? And the co-ordinates which it
gives are what exactly? Because when I tried to plot them up they generated a
really weired plot!
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > Thanks again Johannes,
>
> >
>
> > >
>
> >
>
> > > > Flying bird.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > --My dream is to fly over the rainbow so high!
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > --- In rc_airship_regatta@ yahoogroups. com, "Hannes" <johannes.eissing@
> wrote:
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > > Hello Flying bird,
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > > welcome in our yahoo group. I'm afraid "the detailed procedure of
design" does not exist, or better: differs from design to design. I tried to
write down basic recommendations in Message 505, see
>
> >
>
> > >
>
> >
>
> > > > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/
505>
>
> >
>
> > >
>
> >
>
> > > > > and there is a correction of an equation in message 511, see
>
> >
>
> > >
>
> >
>
> > > > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/
511>
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > > An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > > Try the Series58 Shape Generator for more advanced shapes:
>
> >
>
> > >
>
> >
>
> > > > > <http://www.airshipw orld.info/ software/ 2009/08/generato
r-v06-available/ >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > > Best,
>
> >
>
> > >
>
> >
>
> > > > > Johannes
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > > > --- In rc_airship_regatta@ yahoogroups. com, "flyingkalubird"
<flyingkalubird@ > wrote:
>
> >
>
> > >
>
> >
>
> > > > > >
>
> >
>
> > >
>
> >
>
> > > > > > Hallo everyone here,
>
> >
>
> > >
>
> >
>
> > > > > >
>
> >
>
> > >
>
> >
>
> > > > > > I am planning to build one airship and i have a little knowledge of
the area but not much.
>
> >
>
> > >
>
> >
>
> > > > > > I will be really thankful if some could help me in learning the
design procedure for the airship. Could anyone please put up the detailed
procedure of design step by step. For example the volume and weight calculation,
how to select envelope configuration, how to calculate the gore co-ordinations.
>
> >
>
> > >
>
> >
>
> > > > > >
>
> >
>
> > >
>
> >
>
> > > > > > The design inputs shall be (which can be changed)
>
> >
>
> > >
>
> >
>
> > > > > > 1. Outdoor non-rigid airship.
>
> >
>
> > >
>
> >
>
> > > > > > 2. 10-12 feet sized elliptical - elliptical shaped.
>
> >
>
> > >
>
> >
>
> > > > > > 3. Material for the envelope is PVC.
>
> >
>
> > >
>
> >
>
> > > > > >
>
> >
>
> > >
>
> >
>
> > > > > > I know there are many things I have asked for but still i expect
some replies or at least if someone could give me reference where I can get some
knowledge about the topic.
>
> >
>
> > >
>
> >
>
> > > > > >
>
> >
>
> > >
>
> >
>
> > > > > > Danke Schoen,
>
> >
>
> > >
>
> >
>
> > > > > > Flying bird.
>
> >
>
> > >
>
> >
>
> > > > > >
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> > >
>
> >
>
> > > [Non-text portions of this message have been removed]
>
> >
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> > >
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> > [Non-text portions of this message have been removed]
>
> >
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> [Non-text portions of this message have been removed]
>

Hello Denis,

I have checked that file, its true we will not need any other help, that file
gives all the information required. I am new to this group, who has developed
that file? Its really cool.

And I really want to thank everyone here for their kind help, as I heard people
here are really helpful.

Flying Bird.


--- On Thu, 10/15/09, bowman813 <bowman813@...> wrote:

From: bowman813 <bowman813@...>
Subject: [rc_airship_regatta] Re: Procedure of airship design.
To: rc_airship_regatta@yahoogroups.com
Date: Thursday, October 15, 2009, 7:50 PM






 









Hello Flying bird.



All these informations are very interesting.

When I made my own rc airship, I followed a simple process by using the "airship
design4.xls" file found on this group, very efficient and simple to use. If the
predefined shapes are not sufficient, you can use parameters calculated into
"Series58 Generator". With this method it's not required to have a 3d software
to make the calculations.



Hope that helps...

Denis































[Non-text portions of this message have been removed]

Hello Luftschipper,

Thanks for the guidance again. Could you pls tell me whether I should go for
single motor or with two motors? Your point is valid for the case, the yaw force
will not be good enough unless the levers are long. From everyone's suggestions
I think having a rudder and elevator will be the best bet. And about the weight
and other calculations I will only be able to make any decision unless i decide
the number of motors which I will be using. I was thinking of using two motors
for the only reason that I could use it for differential thrust vectoring! If
one motor can handle it well then I will go for single motor itself. What do you
suggest?

Regards,
Flying Bird.





--- On Thu, 10/15/09, luftschipper <phanick@...> wrote:

From: luftschipper <phanick@...>
Subject: [rc_airship_regatta] Re: Procedure of airship design.
To: rc_airship_regatta@yahoogroups.com
Date: Thursday, October 15, 2009, 11:39 AM






 





                   Hi Flying Bird,



for an outdoor design, I feel that for sufficient pitch control a elevator is
mandatory. Vertical thrust works fine in calm indoor conditions, but outside
there will always be some wind, turbulence, updrafts, downwash and so on. Even
if you feel it was calm, by flying an RC airship you will learn that there is
more motion in the air then you thought. After all, it is an airSHIP, and like
any ship it is carried away by the currents of the see it is swimming in. Be
aware, that your ship will NOT stand still, as long as you do noting at the
controls. The opposite is true: to make it stand on one point, you have to work
hard at the contols. Well, you will see...



To cope with these currents, you need a control system which produces a quick
and strong reaction. A simple aerodynamic rudder/elevator control does provide
this, AS LONG AS YOU FLY FAST ENOUGH, what means, that you need need a
sufficiently powerful motor. Being to slow when flying outside will make your
airship a toy of the wind anyway, even if you install vectored thrust control.
No motor will be able to counteract the effect of even a slight gust hitting the
envelope laterally. The force of the air, pressing laterally (or vertically) on
the huge sail area of the envelope is stronger than any motor of reasonable
size. Thus i feel that tilting the motors is a nice gadget, but for an
outdoorship I think it won't really pay off. (And on an indoor ship I prefer to
have a separate vertical thruster which can be used comletely independent of the
horizontal motors.)



Due to the enormous aerodynamic yaw dampening of the long envelope, controling
the vertical axis by differential thrust will have little effect as long as the
lever from the CG to the thrustline is short compared to the length of the ship,
which it usually is.



Greetings

Luftschipper



--- In rc_airship_regatta@ yahoogroups. com, Flying Bird <flyingkalubird@ ...>
wrote:

>

> Hey luftschipper,

> Â

> Such a lively reply  thank you for

> the reply.

> Â

> As you have rightly pointed out, I was also looking for the step by step

> procedure which you have told. There is no indoor facility available for me

> here so I

> will be going for outdoor design only. And thanks for putting light on result

> prospectives, i will keep that in my mind.

> For the controls, I am planning to go a rudder (Yaw) and a fixed fin for
vertical stabilizing. For Pitch I will tilt the motors (Planning to use two
motors). Will that system do for the airship? And what if we run motors at
different speeds  and we will get yaw motion , Isn't it (Control will be
little difficult though)? I will find the electronic components available and 
will follow the procedure you have told me.

>

> Thanks again,Flying Bird.

>

>

> --- On Thu, 10/15/09, luftschipper <phanick@... > wrote:

>

> From: luftschipper <phanick@... >

> Subject: [rc_airship_ regatta] Re: Procedure of airship design.

> To: rc_airship_regatta@ yahoogroups. com

> Date: Thursday, October 15, 2009, 6:37 AM

>

>

>

>

>

>

> Â

>

>

>

>

>

>                   Hello Flying Bird,

>

>

>

> from your postings requesting a 'design pocedure' I conclude that this will be
your very first airship, right? Up till now this thread was focussed pretty much
on the shape and the design of the envelope. This is indeed an important subject
in airship design, never the less I feel like for a beginner in this trade there
are some other things to be considered beforehand.

>

>

>

> The very first point is: what is the intended pupose of your project? Of
course you will answer something like: It is meant to be the perfect RC-airship
:-). I hope I won't toss you out of this dream too violently when I tell you
that in this case you will fall short of expectations. Most of the people in the
scene will remember their first ship as one that was not very perfect, but one
that helped them to gather a lot of experience.

>

>

>

> I'ld suggest to keep this in mind and to choose a kind of airship well suited
for this purpose. That means for example to build an indoor instead an outdoor
airship, for inflating, rigging, trimming and all the things that have to be
done before flying can begin is much easier to do in a sheltered area. Moreover
you don't have to wait for suitable weather conditions to perform the next test
flight.

>

>

>

> Then you have to decide which kind of control principle you want to use.
control surfaces at the empennage, or control by thrust modulation, or both? how
many motors? motors tilting or rigidly mounted? How much power is necessary?
(Much less on an indoor than on an outdoor ship) From these decisions you have
to derive the necessary components to find out how heavy your equipment and
where the centeres of gravity of the components will be. Together with the
estimations of the masses ot the gondola, empannage, wiring etc. you can find
out how much lift the envelope has to provide.

>

>

>

> Only now it is time to begin the layout of the envelope: how much volume, how
much surface, specific mass of the material, weight of the envelope.. Enough
lift left? No? One more time...

>

>

>

> Oh, not to forget: don't lay out your envelope too tight, I'ld recommend a
surplus lift of at least some 25%. Think that is too much? As a rule, things
become heavier during construction all by them selves. And you will need some
ballast anyway to trim the ship. And, depending on the tightness and the
permeability of your envelope, helium will get out of the envelope and air will
get in, at least if it's inflated over a longer period of time.. Even if you
refill it, the quantity of air diluting the helium will reduce the lift. Having
enough margin enables you to compensate this loss by removing ballast. If you
haven't, your ship may keep stuck to mother earth unless you deflate the
envelope completly and fill it again with new helium. Cumbersome and expensive
game.

>

>

>

> I hope, these lines will help you to build a successful RC airship as much as
Johanne's explanations did before.

>

>

>

> Good luck and up ship!

>

> Luftschipper

>

>

>

> --- In rc_airship_regatta@ yahoogroups. com, Flying Bird <flyingkalubird@ ...>
wrote:

>

> >

>

> > Thanks Johannes once again,

>

> >

>

> > Now almost everything is clear to me. I will work out with this design
problem and quickly start the construction work. I will be using PVC sheets for
the envelope and will seal them using Acetone, I have tried once It works fine,
but don't know whether PVC will be able to take the load or not, anyways that
can be concluded only after realizing it.

>

> > I will come back if there are any other Non-Stupid questions

>

> >

>

> > I have noticed most of the people in this group are from Germany!

>

> >

>

> > Ich lerne Deutsch, ich weiss (I don't know how to type scharfes S) und Ich
spreche etwas Deutsch.

>

> >

>

> >  Danke Schoen,

>

> >

>

> > Flying bird.

>

> >

>

> >

>

> >

>

> > --- On Tue, 10/13/09, Hannes <johannes.eissing@ ...> wrote:

>

> >

>

> > From: Hannes <johannes.eissing@ ...>

>

> > Subject: [rc_airship_ regatta] Re: Procedure of airship design.

>

> > To: rc_airship_regatta@ yahoogroups. com

>

> > Date: Tuesday, October 13, 2009, 9:23 PM

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> > Â

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> > Hi Flying bird,

>

> >

>

> >

>

> >

>

> > you're welcome. Find here a basic helpfile for the Series58 Generator:

>

> >

>

> > http://www.airshipw orld.info/ software/ 2009/08/generato r-v06-available/
comment-page- 1/#comment- 3262

>

> >

>

> > (beware of line breaks within the link)

>

> >

>

> > (heck, I'll attach it below!)

>

> >

>

> > It addresses most of your questions, including proposed values for the
parameters.

>

> >

>

> >

>

> >

>

> > The points generated are pairs of x/y point coordinates. If you try to plot
those in EXCEL or openoffice calc, you must choose "x y plot" as graph type. In
a standard plot type, you will ge one curve of x- ordinates and one curve of
y-absissae, looks weired indeed. In other words, the 1st column of numbers
exported to the clipboard are x- values (lengthwise) , the 2nd column are the
corresponding radii of the body of revolution.

>

> >

>

> >

>

> >

>

> > A saying is "there are no stupid questions, there are stupid answers". Too
often I do forget the world is full on non-flight-physics- engineers, sorry for
this ;o)

>

> >

>

> >

>

> >

>

> > Best, Johannes

>

> >

>

> > PS.: keep us posted about your project, and keep asking questions!

>

> >

>

> > PPS.: A teacher of mine used to say "keep wondering"

>

> >

>

> >

>

> >

>

> > Appendix: Basic Series58 Generator Help file

>

> >

>

> >

>

> >

>

> > Airshipworld Gertler Series 58 Generator â€" Version 0.6
(27.03.2009)

>

> >

>

> > (c) A. Grunewald & J. Eissing

>

> >

>

> > http://www.airshipw orld.info/ software

>

> >

>

> > Helpfile by Johannes Eißing, 18.08.2009

>

> >

>

> >

>

> >

>

> > General

>

> >

>

> >

>

> >

>

> > The Series 58 hullforms were developed by Morton Gertler and Louis Landweber
for the David Taylor Model Basin DTMB in 1950 [1], [2]. These shapes are
described by five parameters such as slenderness ratio, prismatic coefficient,
location of maximum thickness, bow- and sternradius. The series 58 shapes are
well covered in literature because of their parametrics and reproducibility.
Their value for research and development is comparable to the well known NACA
four- and five digit profiles.

>

> >

>

> >

>

> >

>

> > User Interface

>

> >

>

> >

>

> >

>

> > - Render Profile

>

> >

>

> > pretty much self explaining, klicking this button updates the plot window.

>

> >

>

> >

>

> >

>

> > - Copy Values to Clipbord with TAB/semicolon

>

> >

>

> > Points shown in the plot window are copied th the clipbord as x/y point
coordinates. Only the coordinates for the upper shape are exported to the
clipbord. The number of Points "n" is set in the dialogue box "Input
Parameters", see below. Coordinates are given nondimensionally, referred to the
length of the body. Points are allocated in a full cosine distribution. The
delimiting character can be chosen as TAB or semicolon. Chosing the TAB
Character facilitates import to e.g. EXCEL by CNTRL+V

>

> >

>

> >

>

> >

>

> > - Calculated Parameters:

>

> >

>

> > - Cs

>

> >

>

> > Surface Coefficient as introduced by Gertler [1]

>

> >

>

> > Cs = Swet/(L*pi*D) where

>

> >

>

> > Swet = wetted surface area,

>

> >

>

> > L = Length of the body

>

> >

>

> > pi is the ratio of perimeter to diameter of a circle with approximately
3.1416

>

> >

>

> > D is the diameter of the body.

>

> >

>

> > Reversely, wetted surface area is computed by

>

> >

>

> > Swet = Cs*L*pi*D

>

> >

>

> > Cs is calculated numerically, meaning it's accuracy increases with the

>

> >

>

> > number of points n (see Input Parameters). Already with 20 points the

>

> >

>

> > error is less than 0.5%, with 50 points about 0.05%.

>

> >

>

> >

>

> >

>

> > - CB

>

> >

>

> > Centre of buoyancy. This is the volumetric center of the body referred to
the body's length.

>

> >

>

> >

>

> >

>

> > - a1 to a6

>

> >

>

> > are the computed polynomial coefficients for the shape function

>

> >

>

> > y(x)=D*sqrt( a1*(x/L)+ a2*(x/L)^ 2+a3*(x/L) ^3+a4*(x/ L)^4+a5*( x/L)^5+a6*
(x/L)^6)

>

> >

>

> > where

>

> >

>

> > y(x) is the local radius (ordinate)

>

> >

>

> > x is the abscissa

>

> >

>

> > D is the maximum diameter

>

> >

>

> > L is the length of the body.

>

> >

>

> >

>

> >

>

> > - Input Parameters

>

> >

>

> > - n â€" Number of steps

>

> >

>

> > Here, the number of points to be computed for the shape can be set. For
standard use, 20 to 50 points will do.

>

> >

>

> >

>

> >

>

> > - m â€" Point of maximum thickness

>

> >

>

> > This is the position of the maximum section, referred to body length.. A
typical value is 0.40.

>

> >

>

> >

>

> >

>

> > - r0 â€" Dimensionless bow radius

>

> >

>

> > Bow and stern radii are nondimensionalized by the following relationship:

>

> >

>

> > r = R*L/D^2=(R/D) *(L/D) where

>

> >

>

> > r is the nondimensional radius

>

> >

>

> > R is the dimensional radius

>

> >

>

> > L is the Length and

>

> >

>

> > D is the diameter of the body.

>

> >

>

> > A typical value for the bow radius is 0.5, being the bow radius of any
prolate spheroid. A pointed bow would show a value of 0.0.

>

> >

>

> >

>

> >

>

> > - rl â€" Dimensionless stern radius

>

> >

>

> > See above r0. A typical value for a tail radius is 0.1. A pointed tail would
show a value of 0.0.

>

> >

>

> >

>

> >

>

> > - Cp â€" Prismatic coefficient

>

> >

>

> > The overall prismatic coefficient is a measure of how good a slender body
fits an enveloping prism, built from the maximum crossection extruded for the
length of the body. In case of a body of revolution, this prism is a cylinder.
An arbitrary ellipsoid shows a prismatic coefficient of 2/3. Typical values for
airships and submersibles are in the range of 0.60 to 0.70.

>

> >

>

> >

>

> >

>

> > - L2D -Length to Diameter ratio

>

> >

>

> > This is the slenderness ratio of the body, typical values being in the range
between four and ten. A typical value for airships is five.

>

> >

>

> >

>

> >

>

> > References

>

> >

>

> > [1] "Resistance Experiments on a Systematic Series of Streamlined Bodies of
Revolution â€" For Application to the Design of High-Speed Submarines"

>

> >

>

> > DAVID TAYLOR MODEL BASIN WASHINGTON DC

>

> >

>

> > Gertler, Morton, APR 1950

>

> >

>

> > [2] "Mathematical Formulation of Bodies of Revolution"

>

> >

>

> > DAVID TAYLOR MODEL BASIN WASHINGTON DC

>

> >

>

> > Landweber,L. ; Gertler,M., SEP 1950

>

> >

>

> >

>

> >

>

> > --- In rc_airship_regatta@ yahoogroups. com, "Flying" <flyingkalubird@ ...>
wrote:

>

> >

>

> > >

>

> >

>

> > > Hello Johannes,

>

> >

>

> > >

>

> >

>

> > > Thank you so much for the kind reply.

>

> >

>

> > > Could you please tell me something about Series58 Shape Generator?

>

> >

>

> > > What is prismatic coefficient? Rest of the input parameters I know but
what are the optimal values of these inputs for my requirement, that how will I
know?(I know its a stupid question but I really don't know)  How does each
parameter affect the performance of the airship? And the co-ordinates which it
gives are what exactly? Because when I tried to plot them up they generated a
really weired plot!

>

> >

>

> > >

>

> >

>

> > > Thanks again Johannes,

>

> >

>

> > > Flying bird.

>

> >

>

> > >

>

> >

>

> > > --My dream is to fly over the rainbow so high!

>

> >

>

> > >

>

> >

>

> > >

>

> >

>

> > > --- In rc_airship_regatta@ yahoogroups. com, "Hannes" <johannes.eissing@ >
wrote:

>

> >

>

> > > >

>

> >

>

> > > >

>

> >

>

> > > >

>

> >

>

> > > >

>

> >

>

> > > >

>

> >

>

> > > >

>

> >

>

> > > > Hello Flying bird,

>

> >

>

> > > >

>

> >

>

> > > > welcome in our yahoo group. I'm afraid "the detailed procedure of
design" does not exist, or better: differs from design to design. I tried to
write down basic recommendations in Message 505, see

>

> >

>

> > > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 505>

>

> >

>

> > > > and there is a correction of an equation in message 511, see

>

> >

>

> > > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 511>

>

> >

>

> > > >

>

> >

>

> > > > An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.

>

> >

>

> > > >

>

> >

>

> > > > Try the Series58 Shape Generator for more advanced shapes:

>

> >

>

> > > > <http://www.airshipw orld.info/ software/ 2009/08/generato
r-v06-available/ >

>

> >

>

> > > >

>

> >

>

> > > > Best,

>

> >

>

> > > > Johannes

>

> >

>

> > > >

>

> >

>

> > > > --- In rc_airship_regatta@ yahoogroups. com, "flyingkalubird"
<flyingkalubird@ > wrote:

>

> >

>

> > > > >

>

> >

>

> > > > > Hallo everyone here,

>

> >

>

> > > > >

>

> >

>

> > > > > I am planning to build one airship and i have a little knowledge of
the area but not much.

>

> >

>

> > > > > I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.

>

> >

>

> > > > >

>

> >

>

> > > > > The design inputs shall be (which can be changed)

>

> >

>

> > > > > 1. Outdoor non-rigid airship.

>

> >

>

> > > > > 2. 10-12 feet sized elliptical - elliptical shaped.

>

> >

>

> > > > > 3. Material for the envelope is PVC.

>

> >

>

> > > > >

>

> >

>

> > > > > I know there are many things I have asked for but still i expect some
replies or at least if someone could give me reference where I can get some
knowledge about the topic.

>

> >

>

> > > > >

>

> >

>

> > > > > Danke Schoen,

>

> >

>

> > > > > Flying bird.

>

> >

>

> > > > >

>

> >

>

> > > >

>

> >

>

> > >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> >

>

> > [Non-text portions of this message have been removed]

>

> >

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

> [Non-text portions of this message have been removed]

>































[Non-text portions of this message have been removed]

Hello Flying bird.

All these informations are very interesting.
When I made my own rc airship, I followed a simple process by using the "airship
design4.xls" file found on this group, very efficient and simple to use. If the
predefined shapes are not sufficient, you can use parameters calculated into
"Series58 Generator". With this method it's not required to have a 3d software
to make the calculations.

Hope that helps...
Denis

Hi Flying Bird,

for an outdoor design, I feel that for sufficient pitch control a elevator is
mandatory. Vertical thrust works fine in calm indoor conditions, but outside
there will always be some wind, turbulence, updrafts, downwash and so on. Even
if you feel it was calm, by flying an RC airship you will learn that there is
more motion in the air then you thought. After all, it is an airSHIP, and like
any ship it is carried away by the currents of the see it is swimming in. Be
aware, that your ship will NOT stand still, as long as you do noting at the
controls. The opposite is true: to make it stand on one point, you have to work
hard at the contols. Well, you will see...

To cope with these currents, you need a control system which produces a quick
and strong reaction. A simple aerodynamic rudder/elevator control does provide
this, AS LONG AS YOU FLY FAST ENOUGH, what means, that you need need a
sufficiently powerful motor. Being to slow when flying outside will make your
airship a toy of the wind anyway, even if you install vectored thrust control.
No motor will be able to counteract the effect of even a slight gust hitting the
envelope laterally. The force of the air, pressing laterally (or vertically) on
the huge sail area of the envelope is stronger than any motor of reasonable
size. Thus i feel that tilting the motors is a nice gadget, but for an
outdoorship I think it won't really pay off. (And on an indoor ship I prefer to
have a separate vertical thruster which can be used comletely independent of the
horizontal motors.)

Due to the enormous aerodynamic yaw dampening of the long envelope, controling
the vertical axis by differential thrust will have little effect as long as the
lever from the CG to the thrustline is short compared to the length of the ship,
which it usually is.

Greetings
Luftschipper

--- In rc_airship_regatta@yahoogroups.com, Flying Bird <flyingkalubird@...>
wrote:
>
> Hey luftschipper,
>  
> Such a lively reply  thank you for
> the reply.
>  
> As you have rightly pointed out, I was also looking for the step by step
> procedure which you have told. There is no indoor facility available for me
> here so I
> will be going for outdoor design only. And thanks for putting light on result
> prospectives, i will keep that in my mind.
> For the controls, I am planning to go a rudder (Yaw) and a fixed fin for
vertical stabilizing. For Pitch I will tilt the motors (Planning to use two
motors). Will that system do for the airship? And what if we run motors at
different speeds  and we will get yaw motion , Isn't it (Control will be little
difficult though)? I will find the electronic components available and  will
follow the procedure you have told me.
>
> Thanks again,Flying Bird.
>
>
> --- On Thu, 10/15/09, luftschipper <phanick@...> wrote:
>
> From: luftschipper <phanick@...>
> Subject: [rc_airship_regatta] Re: Procedure of airship design.
> To: rc_airship_regatta@yahoogroups.com
> Date: Thursday, October 15, 2009, 6:37 AM
>
>
>
>
>
>
>  
>
>
>
>
>
>                   Hello Flying Bird,
>
>
>
> from your postings requesting a 'design pocedure' I conclude that this will be
your very first airship, right? Up till now this thread was focussed pretty much
on the shape and the design of the envelope. This is indeed an important subject
in airship design, never the less I feel like for a beginner in this trade there
are some other things to be considered beforehand.
>
>
>
> The very first point is: what is the intended pupose of your project? Of
course you will answer something like: It is meant to be the perfect RC-airship
:-). I hope I won't toss you out of this dream too violently when I tell you
that in this case you will fall short of expectations. Most of the people in the
scene will remember their first ship as one that was not very perfect, but one
that helped them to gather a lot of experience.
>
>
>
> I'ld suggest to keep this in mind and to choose a kind of airship well suited
for this purpose. That means for example to build an indoor instead an outdoor
airship, for inflating, rigging, trimming and all the things that have to be
done before flying can begin is much easier to do in a sheltered area. Moreover
you don't have to wait for suitable weather conditions to perform the next test
flight.
>
>
>
> Then you have to decide which kind of control principle you want to use.
control surfaces at the empennage, or control by thrust modulation, or both? how
many motors? motors tilting or rigidly mounted? How much power is necessary?
(Much less on an indoor than on an outdoor ship) From these decisions you have
to derive the necessary components to find out how heavy your equipment and
where the centeres of gravity of the components will be. Together with the
estimations of the masses ot the gondola, empannage, wiring etc. you can find
out how much lift the envelope has to provide.
>
>
>
> Only now it is time to begin the layout of the envelope: how much volume, how
much surface, specific mass of the material, weight of the envelope. Enough lift
left? No? One more time...
>
>
>
> Oh, not to forget: don't lay out your envelope too tight, I'ld recommend a
surplus lift of at least some 25%. Think that is too much? As a rule, things
become heavier during construction all by them selves. And you will need some
ballast anyway to trim the ship. And, depending on the tightness and the
permeability of your envelope, helium will get out of the envelope and air will
get in, at least if it's inflated over a longer period of time. Even if you
refill it, the quantity of air diluting the helium will reduce the lift. Having
enough margin enables you to compensate this loss by removing ballast. If you
haven't, your ship may keep stuck to mother earth unless you deflate the
envelope completly and fill it again with new helium. Cumbersome and expensive
game.
>
>
>
> I hope, these lines will help you to build a successful RC airship as much as
Johanne's explanations did before.
>
>
>
> Good luck and up ship!
>
> Luftschipper
>
>
>
> --- In rc_airship_regatta@ yahoogroups. com, Flying Bird <flyingkalubird@ ...>
wrote:
>
> >
>
> > Thanks Johannes once again,
>
> >
>
> > Now almost everything is clear to me. I will work out with this design
problem and quickly start the construction work. I will be using PVC sheets for
the envelope and will seal them using Acetone, I have tried once It works fine,
but don't know whether PVC will be able to take the load or not, anyways that
can be concluded only after realizing it.
>
> > I will come back if there are any other Non-Stupid questions
>
> >
>
> > I have noticed most of the people in this group are from Germany!
>
> >
>
> > Ich lerne Deutsch, ich weiss (I don't know how to type scharfes S) und Ich
spreche etwas Deutsch.
>
> >
>
> >  Danke Schoen,
>
> >
>
> > Flying bird.
>
> >
>
> >
>
> >
>
> > --- On Tue, 10/13/09, Hannes <johannes.eissing@ ...> wrote:
>
> >
>
> > From: Hannes <johannes.eissing@ ...>
>
> > Subject: [rc_airship_ regatta] Re: Procedure of airship design.
>
> > To: rc_airship_regatta@ yahoogroups. com
>
> > Date: Tuesday, October 13, 2009, 9:23 PM
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > Â
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > Hi Flying bird,
>
> >
>
> >
>
> >
>
> > you're welcome. Find here a basic helpfile for the Series58 Generator:
>
> >
>
> > http://www.airshipw orld.info/ software/ 2009/08/generato r-v06-available/
comment-page- 1/#comment- 3262
>
> >
>
> > (beware of line breaks within the link)
>
> >
>
> > (heck, I'll attach it below!)
>
> >
>
> > It addresses most of your questions, including proposed values for the
parameters.
>
> >
>
> >
>
> >
>
> > The points generated are pairs of x/y point coordinates. If you try to plot
those in EXCEL or openoffice calc, you must choose "x y plot" as graph type. In
a standard plot type, you will ge one curve of x- ordinates and one curve of
y-absissae, looks weired indeed. In other words, the 1st column of numbers
exported to the clipboard are x- values (lengthwise) , the 2nd column are the
corresponding radii of the body of revolution.
>
> >
>
> >
>
> >
>
> > A saying is "there are no stupid questions, there are stupid answers". Too
often I do forget the world is full on non-flight-physics- engineers, sorry for
this ;o)
>
> >
>
> >
>
> >
>
> > Best, Johannes
>
> >
>
> > PS.: keep us posted about your project, and keep asking questions!
>
> >
>
> > PPS.: A teacher of mine used to say "keep wondering"
>
> >
>
> >
>
> >
>
> > Appendix: Basic Series58 Generator Help file
>
> >
>
> >
>
> >
>
> > Airshipworld Gertler Series 58 Generator â€" Version 0.6 (27.03.2009)
>
> >
>
> > (c) A. Grunewald & J. Eissing
>
> >
>
> > http://www.airshipw orld.info/ software
>
> >
>
> > Helpfile by Johannes Eißing, 18.08.2009
>
> >
>
> >
>
> >
>
> > General
>
> >
>
> >
>
> >
>
> > The Series 58 hullforms were developed by Morton Gertler and Louis Landweber
for the David Taylor Model Basin DTMB in 1950 [1], [2]. These shapes are
described by five parameters such as slenderness ratio, prismatic coefficient,
location of maximum thickness, bow- and sternradius. The series 58 shapes are
well covered in literature because of their parametrics and reproducibility.
Their value for research and development is comparable to the well known NACA
four- and five digit profiles.
>
> >
>
> >
>
> >
>
> > User Interface
>
> >
>
> >
>
> >
>
> > - Render Profile
>
> >
>
> > pretty much self explaining, klicking this button updates the plot window.
>
> >
>
> >
>
> >
>
> > - Copy Values to Clipbord with TAB/semicolon
>
> >
>
> > Points shown in the plot window are copied th the clipbord as x/y point
coordinates. Only the coordinates for the upper shape are exported to the
clipbord. The number of Points "n" is set in the dialogue box "Input
Parameters", see below. Coordinates are given nondimensionally, referred to the
length of the body. Points are allocated in a full cosine distribution. The
delimiting character can be chosen as TAB or semicolon. Chosing the TAB
Character facilitates import to e.g. EXCEL by CNTRL+V
>
> >
>
> >
>
> >
>
> > - Calculated Parameters:
>
> >
>
> > - Cs
>
> >
>
> > Surface Coefficient as introduced by Gertler [1]
>
> >
>
> > Cs = Swet/(L*pi*D) where
>
> >
>
> > Swet = wetted surface area,
>
> >
>
> > L = Length of the body
>
> >
>
> > pi is the ratio of perimeter to diameter of a circle with approximately
3.1416
>
> >
>
> > D is the diameter of the body.
>
> >
>
> > Reversely, wetted surface area is computed by
>
> >
>
> > Swet = Cs*L*pi*D
>
> >
>
> > Cs is calculated numerically, meaning it's accuracy increases with the
>
> >
>
> > number of points n (see Input Parameters). Already with 20 points the
>
> >
>
> > error is less than 0.5%, with 50 points about 0.05%.
>
> >
>
> >
>
> >
>
> > - CB
>
> >
>
> > Centre of buoyancy. This is the volumetric center of the body referred to
the body's length.
>
> >
>
> >
>
> >
>
> > - a1 to a6
>
> >
>
> > are the computed polynomial coefficients for the shape function
>
> >
>
> > y(x)=D*sqrt( a1*(x/L)+ a2*(x/L)^ 2+a3*(x/L) ^3+a4*(x/ L)^4+a5*( x/L)^5+a6*
(x/L)^6)
>
> >
>
> > where
>
> >
>
> > y(x) is the local radius (ordinate)
>
> >
>
> > x is the abscissa
>
> >
>
> > D is the maximum diameter
>
> >
>
> > L is the length of the body.
>
> >
>
> >
>
> >
>
> > - Input Parameters
>
> >
>
> > - n â€" Number of steps
>
> >
>
> > Here, the number of points to be computed for the shape can be set. For
standard use, 20 to 50 points will do.
>
> >
>
> >
>
> >
>
> > - m â€" Point of maximum thickness
>
> >
>
> > This is the position of the maximum section, referred to body length. A
typical value is 0.40.
>
> >
>
> >
>
> >
>
> > - r0 â€" Dimensionless bow radius
>
> >
>
> > Bow and stern radii are nondimensionalized by the following relationship:
>
> >
>
> > r = R*L/D^2=(R/D) *(L/D) where
>
> >
>
> > r is the nondimensional radius
>
> >
>
> > R is the dimensional radius
>
> >
>
> > L is the Length and
>
> >
>
> > D is the diameter of the body.
>
> >
>
> > A typical value for the bow radius is 0.5, being the bow radius of any
prolate spheroid. A pointed bow would show a value of 0.0.
>
> >
>
> >
>
> >
>
> > - rl â€" Dimensionless stern radius
>
> >
>
> > See above r0. A typical value for a tail radius is 0.1. A pointed tail would
show a value of 0.0.
>
> >
>
> >
>
> >
>
> > - Cp â€" Prismatic coefficient
>
> >
>
> > The overall prismatic coefficient is a measure of how good a slender body
fits an enveloping prism, built from the maximum crossection extruded for the
length of the body. In case of a body of revolution, this prism is a cylinder.
An arbitrary ellipsoid shows a prismatic coefficient of 2/3. Typical values for
airships and submersibles are in the range of 0.60 to 0.70.
>
> >
>
> >
>
> >
>
> > - L2D -Length to Diameter ratio
>
> >
>
> > This is the slenderness ratio of the body, typical values being in the range
between four and ten. A typical value for airships is five.
>
> >
>
> >
>
> >
>
> > References
>
> >
>
> > [1] "Resistance Experiments on a Systematic Series of Streamlined Bodies of
Revolution â€" For Application to the Design of High-Speed Submarines"
>
> >
>
> > DAVID TAYLOR MODEL BASIN WASHINGTON DC
>
> >
>
> > Gertler, Morton, APR 1950
>
> >
>
> > [2] "Mathematical Formulation of Bodies of Revolution"
>
> >
>
> > DAVID TAYLOR MODEL BASIN WASHINGTON DC
>
> >
>
> > Landweber,L. ; Gertler,M., SEP 1950
>
> >
>
> >
>
> >
>
> > --- In rc_airship_regatta@ yahoogroups. com, "Flying" <flyingkalubird@ ...>
wrote:
>
> >
>
> > >
>
> >
>
> > > Hello Johannes,
>
> >
>
> > >
>
> >
>
> > > Thank you so much for the kind reply.
>
> >
>
> > > Could you please tell me something about Series58 Shape Generator?
>
> >
>
> > > What is prismatic coefficient? Rest of the input parameters I know but
what are the optimal values of these inputs for my requirement, that how will I
know?(I know its a stupid question but I really don't know)  How does each
parameter affect the performance of the airship? And the co-ordinates which it
gives are what exactly? Because when I tried to plot them up they generated a
really weired plot!
>
> >
>
> > >
>
> >
>
> > > Thanks again Johannes,
>
> >
>
> > > Flying bird.
>
> >
>
> > >
>
> >
>
> > > --My dream is to fly over the rainbow so high!
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > --- In rc_airship_regatta@ yahoogroups. com, "Hannes" <johannes.eissing@ >
wrote:
>
> >
>
> > > >
>
> >
>
> > > >
>
> >
>
> > > >
>
> >
>
> > > >
>
> >
>
> > > >
>
> >
>
> > > >
>
> >
>
> > > > Hello Flying bird,
>
> >
>
> > > >
>
> >
>
> > > > welcome in our yahoo group. I'm afraid "the detailed procedure of
design" does not exist, or better: differs from design to design. I tried to
write down basic recommendations in Message 505, see
>
> >
>
> > > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 505>
>
> >
>
> > > > and there is a correction of an equation in message 511, see
>
> >
>
> > > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 511>
>
> >
>
> > > >
>
> >
>
> > > > An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.
>
> >
>
> > > >
>
> >
>
> > > > Try the Series58 Shape Generator for more advanced shapes:
>
> >
>
> > > > <http://www.airshipw orld.info/ software/ 2009/08/generato
r-v06-available/ >
>
> >
>
> > > >
>
> >
>
> > > > Best,
>
> >
>
> > > > Johannes
>
> >
>
> > > >
>
> >
>
> > > > --- In rc_airship_regatta@ yahoogroups. com, "flyingkalubird"
<flyingkalubird@ > wrote:
>
> >
>
> > > > >
>
> >
>
> > > > > Hallo everyone here,
>
> >
>
> > > > >
>
> >
>
> > > > > I am planning to build one airship and i have a little knowledge of
the area but not much.
>
> >
>
> > > > > I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.
>
> >
>
> > > > >
>
> >
>
> > > > > The design inputs shall be (which can be changed)
>
> >
>
> > > > > 1. Outdoor non-rigid airship.
>
> >
>
> > > > > 2. 10-12 feet sized elliptical - elliptical shaped.
>
> >
>
> > > > > 3. Material for the envelope is PVC.
>
> >
>
> > > > >
>
> >
>
> > > > > I know there are many things I have asked for but still i expect some
replies or at least if someone could give me reference where I can get some
knowledge about the topic.
>
> >
>
> > > > >
>
> >
>
> > > > > Danke Schoen,
>
> >
>
> > > > > Flying bird.
>
> >
>
> > > > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > [Non-text portions of this message have been removed]
>
> >
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

Hey luftschipper,
 
Such a lively reply  thank you for
the reply.
 
As you have rightly pointed out, I was also looking for the step by step
procedure which you have told. There is no indoor facility available for me
here so I
will be going for outdoor design only. And thanks for putting light on result
prospectives, i will keep that in my mind.
For the controls, I am planning to go a rudder (Yaw) and a fixed fin for
vertical stabilizing. For Pitch I will tilt the motors (Planning to use two
motors). Will that system do for the airship? And what if we run motors at
different speeds  and we will get yaw motion , Isn't it (Control will be little
difficult though)? I will find the electronic components available and  will
follow the procedure you have told me.

Thanks again,Flying Bird.


--- On Thu, 10/15/09, luftschipper <phanick@...> wrote:

From: luftschipper <phanick@...>
Subject: [rc_airship_regatta] Re: Procedure of airship design.
To: rc_airship_regatta@yahoogroups.com
Date: Thursday, October 15, 2009, 6:37 AM






 





                   Hello Flying Bird,



from your postings requesting a 'design pocedure' I conclude that this will be
your very first airship, right? Up till now this thread was focussed pretty much
on the shape and the design of the envelope. This is indeed an important subject
in airship design, never the less I feel like for a beginner in this trade there
are some other things to be considered beforehand.



The very first point is: what is the intended pupose of your project? Of course
you will answer something like: It is meant to be the perfect RC-airship :-). I
hope I won't toss you out of this dream too violently when I tell you that in
this case you will fall short of expectations. Most of the people in the scene
will remember their first ship as one that was not very perfect, but one that
helped them to gather a lot of experience.



I'ld suggest to keep this in mind and to choose a kind of airship well suited
for this purpose. That means for example to build an indoor instead an outdoor
airship, for inflating, rigging, trimming and all the things that have to be
done before flying can begin is much easier to do in a sheltered area. Moreover
you don't have to wait for suitable weather conditions to perform the next test
flight.



Then you have to decide which kind of control principle you want to use. control
surfaces at the empennage, or control by thrust modulation, or both? how many
motors? motors tilting or rigidly mounted? How much power is necessary? (Much
less on an indoor than on an outdoor ship) From these decisions you have to
derive the necessary components to find out how heavy your equipment and where
the centeres of gravity of the components will be. Together with the estimations
of the masses ot the gondola, empannage, wiring etc. you can find out how much
lift the envelope has to provide.



Only now it is time to begin the layout of the envelope: how much volume, how
much surface, specific mass of the material, weight of the envelope. Enough lift
left? No? One more time...



Oh, not to forget: don't lay out your envelope too tight, I'ld recommend a
surplus lift of at least some 25%. Think that is too much? As a rule, things
become heavier during construction all by them selves. And you will need some
ballast anyway to trim the ship. And, depending on the tightness and the
permeability of your envelope, helium will get out of the envelope and air will
get in, at least if it's inflated over a longer period of time. Even if you
refill it, the quantity of air diluting the helium will reduce the lift. Having
enough margin enables you to compensate this loss by removing ballast. If you
haven't, your ship may keep stuck to mother earth unless you deflate the
envelope completly and fill it again with new helium. Cumbersome and expensive
game.



I hope, these lines will help you to build a successful RC airship as much as
Johanne's explanations did before.



Good luck and up ship!

Luftschipper



--- In rc_airship_regatta@ yahoogroups. com, Flying Bird <flyingkalubird@ ...>
wrote:

>

> Thanks Johannes once again,

>

> Now almost everything is clear to me. I will work out with this design problem
and quickly start the construction work. I will be using PVC sheets for the
envelope and will seal them using Acetone, I have tried once It works fine, but
don't know whether PVC will be able to take the load or not, anyways that can be
concluded only after realizing it.

> I will come back if there are any other Non-Stupid questions

>

> I have noticed most of the people in this group are from Germany!

>

> Ich lerne Deutsch, ich weiss (I don't know how to type scharfes S) und Ich
spreche etwas Deutsch.

>

>  Danke Schoen,

>

> Flying bird.

>

>

>

> --- On Tue, 10/13/09, Hannes <johannes.eissing@ ...> wrote:

>

> From: Hannes <johannes.eissing@ ...>

> Subject: [rc_airship_ regatta] Re: Procedure of airship design.

> To: rc_airship_regatta@ yahoogroups. com

> Date: Tuesday, October 13, 2009, 9:23 PM

>

>

>

>

>

>

> Â

>

>

>

>

>

>

>

>

>

> Hi Flying bird,

>

>

>

> you're welcome. Find here a basic helpfile for the Series58 Generator:

>

> http://www.airshipw orld.info/ software/ 2009/08/generato r-v06-available/
comment-page- 1/#comment- 3262

>

> (beware of line breaks within the link)

>

> (heck, I'll attach it below!)

>

> It addresses most of your questions, including proposed values for the
parameters.

>

>

>

> The points generated are pairs of x/y point coordinates. If you try to plot
those in EXCEL or openoffice calc, you must choose "x y plot" as graph type. In
a standard plot type, you will ge one curve of x- ordinates and one curve of
y-absissae, looks weired indeed. In other words, the 1st column of numbers
exported to the clipboard are x- values (lengthwise) , the 2nd column are the
corresponding radii of the body of revolution.

>

>

>

> A saying is "there are no stupid questions, there are stupid answers". Too
often I do forget the world is full on non-flight-physics- engineers, sorry for
this ;o)

>

>

>

> Best, Johannes

>

> PS.: keep us posted about your project, and keep asking questions!

>

> PPS.: A teacher of mine used to say "keep wondering"

>

>

>

> Appendix: Basic Series58 Generator Help file

>

>

>

> Airshipworld Gertler Series 58 Generator â€" Version 0.6 (27.03.2009)

>

> (c) A. Grunewald & J. Eissing

>

> http://www.airshipw orld.info/ software

>

> Helpfile by Johannes Eißing, 18.08.2009

>

>

>

> General

>

>

>

> The Series 58 hullforms were developed by Morton Gertler and Louis Landweber
for the David Taylor Model Basin DTMB in 1950 [1], [2]. These shapes are
described by five parameters such as slenderness ratio, prismatic coefficient,
location of maximum thickness, bow- and sternradius. The series 58 shapes are
well covered in literature because of their parametrics and reproducibility.
Their value for research and development is comparable to the well known NACA
four- and five digit profiles.

>

>

>

> User Interface

>

>

>

> - Render Profile

>

> pretty much self explaining, klicking this button updates the plot window.

>

>

>

> - Copy Values to Clipbord with TAB/semicolon

>

> Points shown in the plot window are copied th the clipbord as x/y point
coordinates. Only the coordinates for the upper shape are exported to the
clipbord. The number of Points "n" is set in the dialogue box "Input
Parameters", see below. Coordinates are given nondimensionally, referred to the
length of the body. Points are allocated in a full cosine distribution. The
delimiting character can be chosen as TAB or semicolon. Chosing the TAB
Character facilitates import to e.g. EXCEL by CNTRL+V

>

>

>

> - Calculated Parameters:

>

> - Cs

>

> Surface Coefficient as introduced by Gertler [1]

>

> Cs = Swet/(L*pi*D) where

>

> Swet = wetted surface area,

>

> L = Length of the body

>

> pi is the ratio of perimeter to diameter of a circle with approximately 3.1416

>

> D is the diameter of the body.

>

> Reversely, wetted surface area is computed by

>

> Swet = Cs*L*pi*D

>

> Cs is calculated numerically, meaning it's accuracy increases with the

>

> number of points n (see Input Parameters). Already with 20 points the

>

> error is less than 0.5%, with 50 points about 0.05%.

>

>

>

> - CB

>

> Centre of buoyancy. This is the volumetric center of the body referred to the
body's length.

>

>

>

> - a1 to a6

>

> are the computed polynomial coefficients for the shape function

>

> y(x)=D*sqrt( a1*(x/L)+ a2*(x/L)^ 2+a3*(x/L) ^3+a4*(x/ L)^4+a5*( x/L)^5+a6*
(x/L)^6)

>

> where

>

> y(x) is the local radius (ordinate)

>

> x is the abscissa

>

> D is the maximum diameter

>

> L is the length of the body.

>

>

>

> - Input Parameters

>

> - n â€" Number of steps

>

> Here, the number of points to be computed for the shape can be set. For
standard use, 20 to 50 points will do.

>

>

>

> - m â€" Point of maximum thickness

>

> This is the position of the maximum section, referred to body length. A
typical value is 0.40.

>

>

>

> - r0 â€" Dimensionless bow radius

>

> Bow and stern radii are nondimensionalized by the following relationship:

>

> r = R*L/D^2=(R/D) *(L/D) where

>

> r is the nondimensional radius

>

> R is the dimensional radius

>

> L is the Length and

>

> D is the diameter of the body.

>

> A typical value for the bow radius is 0.5, being the bow radius of any prolate
spheroid. A pointed bow would show a value of 0.0.

>

>

>

> - rl â€" Dimensionless stern radius

>

> See above r0. A typical value for a tail radius is 0.1. A pointed tail would
show a value of 0.0.

>

>

>

> - Cp â€" Prismatic coefficient

>

> The overall prismatic coefficient is a measure of how good a slender body fits
an enveloping prism, built from the maximum crossection extruded for the length
of the body. In case of a body of revolution, this prism is a cylinder. An
arbitrary ellipsoid shows a prismatic coefficient of 2/3. Typical values for
airships and submersibles are in the range of 0.60 to 0.70.

>

>

>

> - L2D -Length to Diameter ratio

>

> This is the slenderness ratio of the body, typical values being in the range
between four and ten. A typical value for airships is five.

>

>

>

> References

>

> [1] "Resistance Experiments on a Systematic Series of Streamlined Bodies of
Revolution â€" For Application to the Design of High-Speed Submarines"

>

> DAVID TAYLOR MODEL BASIN WASHINGTON DC

>

> Gertler, Morton, APR 1950

>

> [2] "Mathematical Formulation of Bodies of Revolution"

>

> DAVID TAYLOR MODEL BASIN WASHINGTON DC

>

> Landweber,L. ; Gertler,M., SEP 1950

>

>

>

> --- In rc_airship_regatta@ yahoogroups. com, "Flying" <flyingkalubird@ ...>
wrote:

>

> >

>

> > Hello Johannes,

>

> >

>

> > Thank you so much for the kind reply.

>

> > Could you please tell me something about Series58 Shape Generator?

>

> > What is prismatic coefficient? Rest of the input parameters I know but what
are the optimal values of these inputs for my requirement, that how will I
know?(I know its a stupid question but I really don't know)  How does each
parameter affect the performance of the airship? And the co-ordinates which it
gives are what exactly? Because when I tried to plot them up they generated a
really weired plot!

>

> >

>

> > Thanks again Johannes,

>

> > Flying bird.

>

> >

>

> > --My dream is to fly over the rainbow so high!

>

> >

>

> >

>

> > --- In rc_airship_regatta@ yahoogroups. com, "Hannes" <johannes.eissing@ >
wrote:

>

> > >

>

> > >

>

> > >

>

> > >

>

> > >

>

> > >

>

> > > Hello Flying bird,

>

> > >

>

> > > welcome in our yahoo group. I'm afraid "the detailed procedure of design"
does not exist, or better: differs from design to design. I tried to write down
basic recommendations in Message 505, see

>

> > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 505>

>

> > > and there is a correction of an equation in message 511, see

>

> > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 511>

>

> > >

>

> > > An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.

>

> > >

>

> > > Try the Series58 Shape Generator for more advanced shapes:

>

> > > <http://www.airshipw orld.info/ software/ 2009/08/generato
r-v06-available/ >

>

> > >

>

> > > Best,

>

> > > Johannes

>

> > >

>

> > > --- In rc_airship_regatta@ yahoogroups. com, "flyingkalubird"
<flyingkalubird@ > wrote:

>

> > > >

>

> > > > Hallo everyone here,

>

> > > >

>

> > > > I am planning to build one airship and i have a little knowledge of the
area but not much.

>

> > > > I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.

>

> > > >

>

> > > > The design inputs shall be (which can be changed)

>

> > > > 1. Outdoor non-rigid airship.

>

> > > > 2. 10-12 feet sized elliptical - elliptical shaped.

>

> > > > 3. Material for the envelope is PVC.

>

> > > >

>

> > > > I know there are many things I have asked for but still i expect some
replies or at least if someone could give me reference where I can get some
knowledge about the topic.

>

> > > >

>

> > > > Danke Schoen,

>

> > > > Flying bird.

>

> > > >

>

> > >

>

> >

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

>

> [Non-text portions of this message have been removed]

>































[Non-text portions of this message have been removed]

Hello Flying Bird,

from your postings requesting a 'design pocedure' I conclude that this will be
your very first airship, right? Up till now this thread was focussed pretty much
on the shape and the design of the envelope. This is indeed an important subject
in airship design, never the less I feel like for a beginner in this trade there
are some other things to be considered beforehand.

The very first point is: what is the intended pupose of your project? Of course
you will answer something like: It is meant to be the perfect RC-airship :-). I
hope I won't toss you out of this dream too violently when I tell you that in
this case you will fall short of expectations. Most of the people in the scene
will remember their first ship as one that was not very perfect, but one that
helped them to gather a lot of experience.

I'ld suggest to keep this in mind and to choose a kind of airship well suited
for this purpose. That means for example to build an indoor instead an outdoor
airship, for inflating, rigging, trimming and all the things that have to be
done before flying can begin is much easier to do in a sheltered area. Moreover
you don't have to wait for suitable weather conditions to perform the next test
flight.

Then you have to decide which kind of control principle you want to use. control
surfaces at the empennage, or control by thrust modulation, or both? how many
motors? motors tilting or rigidly mounted? How much power is necessary? (Much
less on an indoor than on an outdoor ship) From these decisions you have to
derive the necessary components to find out how heavy your equipment and where
the centeres of gravity of the components will be. Together with the estimations
of the masses ot the gondola, empannage, wiring etc. you can find out how much
lift the envelope has to provide.

Only now it is time to begin the layout of the envelope: how much volume, how
much surface, specific mass of the material, weight of the envelope. Enough lift
left? No? One more time...

Oh, not to forget: don't lay out your envelope too tight, I'ld recommend a
surplus lift of at least some 25%. Think that is too much? As a rule, things
become heavier during construction all by them selves. And you will need some
ballast anyway to trim the ship. And, depending on the tightness and the
permeability of your envelope, helium will get out of the envelope and air will
get in, at least if it's inflated over a longer period of time. Even if you
refill it, the quantity of air diluting the helium will reduce the lift. Having
enough margin enables you to compensate this loss by removing ballast. If you
haven't, your ship may keep stuck to mother earth unless you deflate the
envelope completly and fill it again with new helium. Cumbersome and expensive
game.

I hope, these lines will help you to build a successful RC airship as much as
Johanne's explanations did before.

Good luck and up ship!
Luftschipper

--- In rc_airship_regatta@yahoogroups.com, Flying Bird <flyingkalubird@...>
wrote:
>
> Thanks Johannes once again,
>
> Now almost everything is clear to me. I will work out with this design problem
and quickly start the construction work. I will be using PVC sheets for the
envelope and will seal them using Acetone, I have tried once It works fine, but
don't know whether PVC will be able to take the load or not, anyways that can be
concluded only after realizing it.
> I will come back if there are any other Non-Stupid questions
>
> I have noticed most of the people in this group are from Germany!
>
> Ich lerne Deutsch, ich weiss (I don't know how to type scharfes S) und Ich
spreche etwas Deutsch.
>
>  Danke Schoen,
>
> Flying bird.
>
>
>
> --- On Tue, 10/13/09, Hannes <johannes.eissing@...> wrote:
>
> From: Hannes <johannes.eissing@...>
> Subject: [rc_airship_regatta] Re: Procedure of airship design.
> To: rc_airship_regatta@yahoogroups.com
> Date: Tuesday, October 13, 2009, 9:23 PM
>
>
>
>
>
>
>  
>
>
>
>
>
>
>
>
>
> Hi Flying bird,
>
>
>
> you're welcome. Find here a basic helpfile for the Series58 Generator:
>
> http://www.airshipw orld.info/ software/ 2009/08/generato r-v06-available/
comment-page- 1/#comment- 3262
>
> (beware of line breaks within the link)
>
> (heck, I'll attach it below!)
>
> It addresses most of your questions, including proposed values for the
parameters.
>
>
>
> The points generated are pairs of x/y point coordinates. If you try to plot
those in EXCEL or openoffice calc, you must choose "x y plot" as graph type. In
a standard plot type, you will ge one curve of x- ordinates and one curve of
y-absissae, looks weired indeed. In other words, the 1st column of numbers
exported to the clipboard are x- values (lengthwise) , the 2nd column are the
corresponding radii of the body of revolution.
>
>
>
> A saying is "there are no stupid questions, there are stupid answers". Too
often I do forget the world is full on non-flight-physics- engineers, sorry for
this ;o)
>
>
>
> Best, Johannes
>
> PS.: keep us posted about your project, and keep asking questions!
>
> PPS.: A teacher of mine used to say "keep wondering"
>
>
>
> Appendix: Basic Series58 Generator Help file
>
>
>
> Airshipworld Gertler Series 58 Generator â€" Version 0.6 (27.03.2009)
>
> (c) A. Grunewald & J. Eissing
>
> http://www.airshipw orld.info/ software
>
> Helpfile by Johannes Eißing, 18.08.2009
>
>
>
> General
>
>
>
> The Series 58 hullforms were developed by Morton Gertler and Louis Landweber
for the David Taylor Model Basin DTMB in 1950 [1], [2]. These shapes are
described by five parameters such as slenderness ratio, prismatic coefficient,
location of maximum thickness, bow- and sternradius. The series 58 shapes are
well covered in literature because of their parametrics and reproducibility.
Their value for research and development is comparable to the well known NACA
four- and five digit profiles.
>
>
>
> User Interface
>
>
>
> - Render Profile
>
> pretty much self explaining, klicking this button updates the plot window.
>
>
>
> - Copy Values to Clipbord with TAB/semicolon
>
> Points shown in the plot window are copied th the clipbord as x/y point
coordinates. Only the coordinates for the upper shape are exported to the
clipbord. The number of Points "n" is set in the dialogue box "Input
Parameters", see below. Coordinates are given nondimensionally, referred to the
length of the body. Points are allocated in a full cosine distribution. The
delimiting character can be chosen as TAB or semicolon. Chosing the TAB
Character facilitates import to e.g. EXCEL by CNTRL+V
>
>
>
> - Calculated Parameters:
>
> - Cs
>
> Surface Coefficient as introduced by Gertler [1]
>
> Cs = Swet/(L*pi*D) where
>
> Swet = wetted surface area,
>
> L = Length of the body
>
> pi is the ratio of perimeter to diameter of a circle with approximately 3.1416
>
> D is the diameter of the body.
>
> Reversely, wetted surface area is computed by
>
> Swet = Cs*L*pi*D
>
> Cs is calculated numerically, meaning it's accuracy increases with the
>
> number of points n (see Input Parameters). Already with 20 points the
>
> error is less than 0.5%, with 50 points about 0.05%.
>
>
>
> - CB
>
> Centre of buoyancy. This is the volumetric center of the body referred to the
body's length.
>
>
>
> - a1 to a6
>
> are the computed polynomial coefficients for the shape function
>
> y(x)=D*sqrt( a1*(x/L)+ a2*(x/L)^ 2+a3*(x/L) ^3+a4*(x/ L)^4+a5*( x/L)^5+a6*
(x/L)^6)
>
> where
>
> y(x) is the local radius (ordinate)
>
> x is the abscissa
>
> D is the maximum diameter
>
> L is the length of the body.
>
>
>
> - Input Parameters
>
> - n â€" Number of steps
>
> Here, the number of points to be computed for the shape can be set. For
standard use, 20 to 50 points will do.
>
>
>
> - m â€" Point of maximum thickness
>
> This is the position of the maximum section, referred to body length. A
typical value is 0.40.
>
>
>
> - r0 â€" Dimensionless bow radius
>
> Bow and stern radii are nondimensionalized by the following relationship:
>
> r = R*L/D^2=(R/D) *(L/D) where
>
> r is the nondimensional radius
>
> R is the dimensional radius
>
> L is the Length and
>
> D is the diameter of the body.
>
> A typical value for the bow radius is 0.5, being the bow radius of any prolate
spheroid. A pointed bow would show a value of 0.0.
>
>
>
> - rl â€" Dimensionless stern radius
>
> See above r0. A typical value for a tail radius is 0.1. A pointed tail would
show a value of 0.0.
>
>
>
> - Cp â€" Prismatic coefficient
>
> The overall prismatic coefficient is a measure of how good a slender body fits
an enveloping prism, built from the maximum crossection extruded for the length
of the body. In case of a body of revolution, this prism is a cylinder. An
arbitrary ellipsoid shows a prismatic coefficient of 2/3. Typical values for
airships and submersibles are in the range of 0.60 to 0.70.
>
>
>
> - L2D -Length to Diameter ratio
>
> This is the slenderness ratio of the body, typical values being in the range
between four and ten. A typical value for airships is five.
>
>
>
> References
>
> [1] "Resistance Experiments on a Systematic Series of Streamlined Bodies of
Revolution â€" For Application to the Design of High-Speed Submarines"
>
> DAVID TAYLOR MODEL BASIN WASHINGTON DC
>
> Gertler, Morton, APR 1950
>
> [2] "Mathematical Formulation of Bodies of Revolution"
>
> DAVID TAYLOR MODEL BASIN WASHINGTON DC
>
> Landweber,L. ; Gertler,M., SEP 1950
>
>
>
> --- In rc_airship_regatta@ yahoogroups. com, "Flying" <flyingkalubird@ ...>
wrote:
>
> >
>
> > Hello Johannes,
>
> >
>
> > Thank you so much for the kind reply.
>
> > Could you please tell me something about Series58 Shape Generator?
>
> > What is prismatic coefficient? Rest of the input parameters I know but what
are the optimal values of these inputs for my requirement, that how will I
know?(I know its a stupid question but I really don't know)  How does each
parameter affect the performance of the airship? And the co-ordinates which it
gives are what exactly? Because when I tried to plot them up they generated a
really weired plot!
>
> >
>
> > Thanks again Johannes,
>
> > Flying bird.
>
> >
>
> > --My dream is to fly over the rainbow so high!
>
> >
>
> >
>
> > --- In rc_airship_regatta@ yahoogroups. com, "Hannes" <johannes.eissing@ >
wrote:
>
> > >
>
> > >
>
> > >
>
> > >
>
> > >
>
> > >
>
> > > Hello Flying bird,
>
> > >
>
> > > welcome in our yahoo group. I'm afraid "the detailed procedure of design"
does not exist, or better: differs from design to design. I tried to write down
basic recommendations in Message 505, see
>
> > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 505>
>
> > > and there is a correction of an equation in message 511, see
>
> > > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 511>
>
> > >
>
> > > An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.
>
> > >
>
> > > Try the Series58 Shape Generator for more advanced shapes:
>
> > > <http://www.airshipw orld.info/ software/ 2009/08/generato
r-v06-available/>
>
> > >
>
> > > Best,
>
> > > Johannes
>
> > >
>
> > > --- In rc_airship_regatta@ yahoogroups. com, "flyingkalubird"
<flyingkalubird@ > wrote:
>
> > > >
>
> > > > Hallo everyone here,
>
> > > >
>
> > > > I am planning to build one airship and i have a little knowledge of the
area but not much.
>
> > > > I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.
>
> > > >
>
> > > > The design inputs shall be (which can be changed)
>
> > > > 1. Outdoor non-rigid airship.
>
> > > > 2. 10-12 feet sized elliptical - elliptical shaped.
>
> > > > 3. Material for the envelope is PVC.
>
> > > >
>
> > > > I know there are many things I have asked for but still i expect some
replies or at least if someone could give me reference where I can get some
knowledge about the topic.
>
> > > >
>
> > > > Danke Schoen,
>
> > > > Flying bird.
>
> > > >
>
> > >
>
> >
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

Thanks Johannes once again,

Now almost everything is clear to me. I will work out with this design problem
and quickly start the construction work. I will be using PVC sheets for the
envelope and will seal them using Acetone, I have tried once It works fine, but
don't know whether PVC will be able to take the load or not, anyways that can be
concluded only after realizing it.
I will come back if there are any other Non-Stupid questions

I have noticed most of the people in this group are from Germany!

Ich lerne Deutsch, ich weiss (I don't know how to type scharfes S) und Ich
spreche etwas Deutsch.

  Danke Schoen,

Flying bird.



--- On Tue, 10/13/09, Hannes <johannes.eissing@...> wrote:

From: Hannes <johannes.eissing@...>
Subject: [rc_airship_regatta] Re: Procedure of airship design.
To: rc_airship_regatta@yahoogroups.com
Date: Tuesday, October 13, 2009, 9:23 PM






 









Hi Flying bird,



you're welcome. Find here a basic helpfile for the Series58 Generator:

http://www.airshipw orld.info/ software/ 2009/08/generato r-v06-available/
comment-page- 1/#comment- 3262

(beware of line breaks within the link)

(heck, I'll attach it below!)

It addresses most of your questions, including proposed values for the
parameters.



The points generated are pairs of x/y point coordinates. If you try to plot
those in EXCEL or openoffice calc, you must choose "x y plot" as graph type. In
a standard plot type, you will ge one curve of x- ordinates and one curve of
y-absissae, looks weired indeed. In other words, the 1st column of numbers
exported to the clipboard are x- values (lengthwise) , the 2nd column are the
corresponding radii of the body of revolution.



A saying is "there are no stupid questions, there are stupid answers". Too often
I do forget the world is full on non-flight-physics- engineers, sorry for this
;o)



Best, Johannes

PS.: keep us posted about your project, and keep asking questions!

PPS.: A teacher of mine used to say "keep wondering"



Appendix: Basic Series58 Generator Help file



Airshipworld Gertler Series 58 Generator – Version 0.6 (27.03.2009)

(c) A. Grunewald & J. Eissing

http://www.airshipw orld.info/ software

Helpfile by Johannes Eißing, 18.08.2009



General



The Series 58 hullforms were developed by Morton Gertler and Louis Landweber for
the David Taylor Model Basin DTMB in 1950 [1], [2]. These shapes are described
by five parameters such as slenderness ratio, prismatic coefficient, location of
maximum thickness, bow- and sternradius. The series 58 shapes are well covered
in literature because of their parametrics and reproducibility. Their value for
research and development is comparable to the well known NACA four- and five
digit profiles.



User Interface



- Render Profile

pretty much self explaining, klicking this button updates the plot window.



- Copy Values to Clipbord with TAB/semicolon

Points shown in the plot window are copied th the clipbord as x/y point
coordinates. Only the coordinates for the upper shape are exported to the
clipbord. The number of Points "n" is set in the dialogue box "Input
Parameters", see below. Coordinates are given nondimensionally, referred to the
length of the body. Points are allocated in a full cosine distribution. The
delimiting character can be chosen as TAB or semicolon. Chosing the TAB
Character facilitates import to e.g. EXCEL by CNTRL+V



- Calculated Parameters:

- Cs

Surface Coefficient as introduced by Gertler [1]

Cs = Swet/(L*pi*D) where

Swet = wetted surface area,

L = Length of the body

pi is the ratio of perimeter to diameter of a circle with approximately 3.1416

D is the diameter of the body.

Reversely, wetted surface area is computed by

Swet = Cs*L*pi*D

Cs is calculated numerically, meaning it's accuracy increases with the

number of points n (see Input Parameters). Already with 20 points the

error is less than 0.5%, with 50 points about 0.05%.



- CB

Centre of buoyancy. This is the volumetric center of the body referred to the
body's length.



- a1 to a6

are the computed polynomial coefficients for the shape function

y(x)=D*sqrt( a1*(x/L)+ a2*(x/L)^ 2+a3*(x/L) ^3+a4*(x/ L)^4+a5*( x/L)^5+a6*
(x/L)^6)

where

y(x) is the local radius (ordinate)

x is the abscissa

D is the maximum diameter

L is the length of the body.



- Input Parameters

- n – Number of steps

Here, the number of points to be computed for the shape can be set. For standard
use, 20 to 50 points will do.



- m – Point of maximum thickness

This is the position of the maximum section, referred to body length. A typical
value is 0.40.



- r0 – Dimensionless bow radius

Bow and stern radii are nondimensionalized by the following relationship:

r = R*L/D^2=(R/D) *(L/D) where

r is the nondimensional radius

R is the dimensional radius

L is the Length and

D is the diameter of the body.

A typical value for the bow radius is 0.5, being the bow radius of any prolate
spheroid. A pointed bow would show a value of 0.0.



- rl – Dimensionless stern radius

See above r0. A typical value for a tail radius is 0.1. A pointed tail would
show a value of 0.0.



- Cp – Prismatic coefficient

The overall prismatic coefficient is a measure of how good a slender body fits
an enveloping prism, built from the maximum crossection extruded for the length
of the body. In case of a body of revolution, this prism is a cylinder. An
arbitrary ellipsoid shows a prismatic coefficient of 2/3. Typical values for
airships and submersibles are in the range of 0.60 to 0.70.



- L2D -Length to Diameter ratio

This is the slenderness ratio of the body, typical values being in the range
between four and ten. A typical value for airships is five.



References

[1] "Resistance Experiments on a Systematic Series of Streamlined Bodies of
Revolution – For Application to the Design of High-Speed Submarines"

DAVID TAYLOR MODEL BASIN WASHINGTON DC

Gertler, Morton, APR 1950

[2] "Mathematical Formulation of Bodies of Revolution"

DAVID TAYLOR MODEL BASIN WASHINGTON DC

Landweber,L. ; Gertler,M., SEP 1950



--- In rc_airship_regatta@ yahoogroups. com, "Flying" <flyingkalubird@ ...>
wrote:

>

> Hello Johannes,

>

> Thank you so much for the kind reply.

> Could you please tell me something about Series58 Shape Generator?

> What is prismatic coefficient? Rest of the input parameters I know but what
are the optimal values of these inputs for my requirement, that how will I
know?(I know its a stupid question but I really don't know)  How does each
parameter affect the performance of the airship? And the co-ordinates which it
gives are what exactly? Because when I tried to plot them up they generated a
really weired plot!

>

> Thanks again Johannes,

> Flying bird.

>

> --My dream is to fly over the rainbow so high!

>

>

> --- In rc_airship_regatta@ yahoogroups. com, "Hannes" <johannes.eissing@ >
wrote:

> >

> >

> >

> >

> >

> >

> > Hello Flying bird,

> >

> > welcome in our yahoo group. I'm afraid "the detailed procedure of design"
does not exist, or better: differs from design to design. I tried to write down
basic recommendations in Message 505, see

> > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 505>

> > and there is a correction of an equation in message 511, see

> > <http://tech. groups.yahoo. com/group/ rc_airship_ regatta/message/ 511>

> >

> > An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.

> >

> > Try the Series58 Shape Generator for more advanced shapes:

> > <http://www.airshipw orld.info/ software/ 2009/08/generato r-v06-available/>

> >

> > Best,

> > Johannes

> >

> > --- In rc_airship_regatta@ yahoogroups. com, "flyingkalubird"
<flyingkalubird@ > wrote:

> > >

> > > Hallo everyone here,

> > >

> > > I am planning to build one airship and i have a little knowledge of the
area but not much.

> > > I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.

> > >

> > > The design inputs shall be (which can be changed)

> > > 1. Outdoor non-rigid airship.

> > > 2. 10-12 feet sized elliptical - elliptical shaped.

> > > 3. Material for the envelope is PVC.

> > >

> > > I know there are many things I have asked for but still i expect some
replies or at least if someone could give me reference where I can get some
knowledge about the topic.

> > >

> > > Danke Schoen,

> > > Flying bird.

> > >

> >

>































[Non-text portions of this message have been removed]

Hi Flying bird,

you're welcome. Find here a basic helpfile for the Series58 Generator:
http://www.airshipworld.info/software/2009/08/generator-v06-available/comment-pa\
ge-1/#comment-3262
(beware of line breaks within the link)
(heck, I'll attach it below!)
It addresses most of your questions, including proposed values for the
parameters.

The points generated are pairs of x/y point coordinates. If you try to plot
those in EXCEL or openoffice calc, you must choose "x y plot" as graph type. In
a standard plot type, you will ge one curve of x- ordinates and one curve of
y-absissae, looks weired indeed. In other words, the 1st column of numbers
exported to the clipboard are x- values (lengthwise), the 2nd column are the
corresponding radii of the body of revolution.

A saying is "there are no stupid questions, there are stupid answers". Too often
I do forget the world is full on non-flight-physics-engineers, sorry for this
;o)

Best, Johannes
PS.: keep us posted about your project, and keep asking questions!
PPS.: A teacher of mine used to say "keep wondering"


Appendix: Basic Series58 Generator Help file

Airshipworld Gertler Series 58 Generator – Version 0.6 (27.03.2009)
(c) A. Grunewald & J. Eissing
http://www.airshipworld.info/software
Helpfile by Johannes Eißing, 18.08.2009

General

The Series 58 hullforms were developed by Morton Gertler and Louis Landweber for
the David Taylor Model Basin DTMB in 1950 [1], [2]. These shapes are described
by five parameters such as slenderness ratio, prismatic coefficient, location of
maximum thickness, bow- and sternradius. The series 58 shapes are well covered
in literature because of their parametrics and reproducibility. Their value for
research and development is comparable to the well known NACA four- and five
digit profiles.

User Interface

- Render Profile
pretty much self explaining, klicking this button updates the plot window.

- Copy Values to Clipbord with TAB/semicolon
Points shown in the plot window are copied th the clipbord as x/y point
coordinates. Only the coordinates for the upper shape are exported to the
clipbord. The number of Points "n" is set in the dialogue box "Input
Parameters", see below. Coordinates are given nondimensionally, referred to the
length of the body. Points are allocated in a full cosine distribution. The
delimiting character can be chosen as TAB or semicolon. Chosing the TAB
Character facilitates import to e.g. EXCEL by CNTRL+V

- Calculated Parameters:
- Cs
Surface Coefficient as introduced by Gertler [1]
Cs = Swet/(L*pi*D) where
Swet = wetted surface area,
L = Length of the body
pi is the ratio of perimeter to diameter of a circle with approximately 3.1416
D is the diameter of the body.
Reversely, wetted surface area is computed by
Swet = Cs*L*pi*D
Cs is calculated numerically, meaning it's accuracy increases with the
number of points n (see Input Parameters). Already with 20 points the
error is less than 0.5%, with 50 points about 0.05%.

- CB
Centre of buoyancy. This is the volumetric center of the body referred to the
body's length.

- a1 to a6
are the computed polynomial coefficients for the shape function
y(x)=D*sqrt(a1*(x/L)+a2*(x/L)^2+a3*(x/L)^3+a4*(x/L)^4+a5*(x/L)^5+a6*(x/L)^6)
where
y(x) is the local radius (ordinate)
x is the abscissa
D is the maximum diameter
L is the length of the body.

- Input Parameters
- n – Number of steps
Here, the number of points to be computed for the shape can be set. For standard
use, 20 to 50 points will do.

- m – Point of maximum thickness
This is the position of the maximum section, referred to body length. A typical
value is 0.40.

- r0 – Dimensionless bow radius
Bow and stern radii are nondimensionalized by the following relationship:
r = R*L/D^2=(R/D)*(L/D) where
r is the nondimensional radius
R is the dimensional radius
L is the Length and
D is the diameter of the body.
A typical value for the bow radius is 0.5, being the bow radius of any prolate
spheroid. A pointed bow would show a value of 0.0.

- rl – Dimensionless stern radius
See above r0. A typical value for a tail radius is 0.1. A pointed tail would
show a value of 0.0.

- Cp – Prismatic coefficient
The overall prismatic coefficient is a measure of how good a slender body fits
an enveloping prism, built from the maximum crossection extruded for the length
of the body. In case of a body of revolution, this prism is a cylinder. An
arbitrary ellipsoid shows a prismatic coefficient of 2/3. Typical values for
airships and submersibles are in the range of 0.60 to 0.70.

- L2D -Length to Diameter ratio
This is the slenderness ratio of the body, typical values being in the range
between four and ten. A typical value for airships is five.

References
[1] "Resistance Experiments on a Systematic Series of Streamlined Bodies of
Revolution – For Application to the Design of High-Speed Submarines"
DAVID TAYLOR MODEL BASIN WASHINGTON DC
Gertler, Morton, APR 1950
[2] "Mathematical Formulation of Bodies of Revolution"
DAVID TAYLOR MODEL BASIN WASHINGTON DC
Landweber,L. ; Gertler,M., SEP 1950


--- In rc_airship_regatta@yahoogroups.com, "Flying" <flyingkalubird@...> wrote:
>
> Hello Johannes,
>
> Thank you so much for the kind reply.
> Could you please tell me something about Series58 Shape Generator?
> What is prismatic coefficient? Rest of the input parameters I know but what
are the optimal values of these inputs for my requirement, that how will I
know?(I know its a stupid question but I really don't know)  How does each
parameter affect the performance of the airship? And the co-ordinates which it
gives are what exactly? Because when I tried to plot them up they generated a
really weired plot!
>
> Thanks again Johannes,
> Flying bird.
>
> --My dream is to fly over the rainbow so high!
>
>
> --- In rc_airship_regatta@yahoogroups.com, "Hannes" <johannes.eissing@> wrote:
> >
> >
> >
> >
> >
> >
> > Hello Flying bird,
> >
> > welcome in our yahoo group. I'm afraid "the detailed procedure of design"
does not exist, or better: differs from design to design. I tried to write down
basic recommendations in Message 505, see
> > <http://tech.groups.yahoo.com/group/rc_airship_regatta/message/505>
> > and there is a correction of an equation in message 511, see
> > <http://tech.groups.yahoo.com/group/rc_airship_regatta/message/511>
> >
> > An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.
> >
> > Try the Series58 Shape Generator for more advanced shapes:
> > <http://www.airshipworld.info/software/2009/08/generator-v06-available/>
> >
> > Best,
> > Johannes
> >
> > --- In rc_airship_regatta@yahoogroups.com, "flyingkalubird"
<flyingkalubird@> wrote:
> > >
> > > Hallo everyone here,
> > >
> > > I am planning to build one airship and i have a little knowledge of the
area but not much.
> > > I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.
> > >
> > > The design inputs shall be (which can be changed)
> > > 1. Outdoor non-rigid airship.
> > > 2. 10-12 feet sized elliptical - elliptical shaped.
> > > 3. Material for the envelope is PVC.
> > >
> > > I know there are many things I have asked for but still i expect some
replies or at least if someone could give me reference where I can get some
knowledge about the topic.
> > >
> > > Danke Schoen,
> > > Flying bird.
> > >
> >
>

Hello Johannes,

Thank you so much for the kind reply.
Could you please tell me something about Series58 Shape Generator?
What is prismatic coefficient? Rest of the input parameters I know but what are
the optimal values of these inputs for my requirement, that how will I know?(I
know its a stupid question but I really don't know)  How does each parameter
affect the performance of the airship? And the co-ordinates which it gives are
what exactly? Because when I tried to plot them up they generated a really
weired plot!

Thanks again Johannes,
Flying bird.

--My dream is to fly over the rainbow so high!


--- In rc_airship_regatta@yahoogroups.com, "Hannes" <johannes.eissing@...>
wrote:
>
>
>
>
>
>
> Hello Flying bird,
>
> welcome in our yahoo group. I'm afraid "the detailed procedure of design" does
not exist, or better: differs from design to design. I tried to write down basic
recommendations in Message 505, see
> <http://tech.groups.yahoo.com/group/rc_airship_regatta/message/505>
> and there is a correction of an equation in message 511, see
> <http://tech.groups.yahoo.com/group/rc_airship_regatta/message/511>
>
> An elliptical shape is better than a cylinder, but has two major
disadvantages. 1st the centre of buoyancy CB is right in the middle. It is
advantageous to place the CB more 'bowwards' (?), see message 505. 2nd the stern
of a prolate ellipsoid is relatively bluff, what can lead to flow separations
and hence more drag.
>
> Try the Series58 Shape Generator for more advanced shapes:
> <http://www.airshipworld.info/software/2009/08/generator-v06-available/>
>
> Best,
> Johannes
>
> --- In rc_airship_regatta@yahoogroups.com, "flyingkalubird" <flyingkalubird@>
wrote:
> >
> > Hallo everyone here,
> >
> > I am planning to build one airship and i have a little knowledge of the area
but not much.
> > I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.
> >
> > The design inputs shall be (which can be changed)
> > 1. Outdoor non-rigid airship.
> > 2. 10-12 feet sized elliptical - elliptical shaped.
> > 3. Material for the envelope is PVC.
> >
> > I know there are many things I have asked for but still i expect some
replies or at least if someone could give me reference where I can get some
knowledge about the topic.
> >
> > Danke Schoen,
> > Flying bird.
> >
>

Hello Flying bird,

welcome in our yahoo group. I'm afraid "the detailed procedure of design" does
not exist, or better: differs from design to design. I tried to write down basic
recommendations in Message 505, see
<http://tech.groups.yahoo.com/group/rc_airship_regatta/message/505>
and there is a correction of an equation in message 511, see
<http://tech.groups.yahoo.com/group/rc_airship_regatta/message/511>

An elliptical shape is better than a cylinder, but has two major disadvantages.
1st the centre of buoyancy CB is right in the middle. It is advantageous to
place the CB more 'bowwards' (?), see message 505. 2nd the stern of a prolate
ellipsoid is relatively bluff, what can lead to flow separations and hence more
drag.

Try the Series58 Shape Generator for more advanced shapes:
<http://www.airshipworld.info/software/2009/08/generator-v06-available/>

Best,
Johannes

--- In rc_airship_regatta@yahoogroups.com, "flyingkalubird" <flyingkalubird@...>
wrote:
>
> Hallo everyone here,
>
> I am planning to build one airship and i have a little knowledge of the area
but not much.
> I will be really thankful if some could help me in learning the design
procedure for the airship. Could anyone please put up the detailed procedure of
design step by step. For example the volume and weight calculation, how to
select envelope configuration, how to calculate the gore co-ordinations.
>
> The design inputs shall be (which can be changed)
> 1. Outdoor non-rigid airship.
> 2. 10-12 feet sized elliptical - elliptical shaped.
> 3. Material for the envelope is PVC.
>
> I know there are many things I have asked for but still i expect some replies
or at least if someone could give me reference where I can get some knowledge
about the topic.
>
> Danke Schoen,
> Flying bird.
>

Hallo everyone here,

I am planning to build one airship and i have a little knowledge of the area but
not much.
I will be really thankful if some could help me in learning the design procedure
for the airship. Could anyone please put up the detailed procedure of design
step by step. For example the volume and weight calculation, how to select
envelope configuration, how to calculate the gore co-ordinations.

The design inputs shall be (which can be changed)
1. Outdoor non-rigid airship.
2. 10-12 feet sized elliptical - elliptical shaped.
3. Material for the envelope is PVC.

I know there are many things I have asked for but still i expect some replies or
at least if someone could give me reference where I can get some knowledge about
the topic.

Danke Schoen,
Flying bird.

(English version see below)

Hallo zusammen,

am

Donnerstag, 24.09.2009, 19 Uhr

halte ich einen Vortrag im Zeppelin Museum in Friedrichshafen, hier die
Vorankündigung aus dem Newsletter
<http://www.zeppelin-museum.de/1142.0.html#Donnerstagabend>   des
Museums:

Flugphysik für Einsteiger

Vortrag von Dipl.-Ing. Johannes Eissing, ZLT Luftschifftechnik

Was ist eigentlich Flugphysik, was macht ein Flugphysik-Ingenieur so den
ganzen Tag, und was unterscheidet ein Luftschiff von einem Flugzeug? Der
Vortrag wendet sich an den technisch interessierten Zuhörer, der aber
kein Spezialwissen mitbringen muss. Die Aufgaben der Flugphysik bei der
Zulassung und beim Betrieb von Luftschiffen werden anschaulich
erklärt. Aerodynamik, Aerostatik und Flugmechanik werden anhand der
verschiedenen Modelle beleuchtet, mit denen die Flugphysik versucht, ein
anspruchsvolles Themengebiet handzahm zu machen.

Der Eintritt ist frei.



Ihr Ansprechpartner:

Dipl.-Ing. Johannes Eissing

Flugphysik, Berechnung und Simulation

ZLT Zeppelin Luftschifftechnik GmbH & Co KG

Allmannsweilerstrasse 132

88046 Friedrichshafen | Germany

Tel.: +49 (0) 7541 5900-533

Fax: +49 (0) 7541 5900-22533

j.eissing (at) zeppelin-nt.de



(English version)

Hi all,

I'll do a presentation about Flight Physics in the Zeppelin Museum in
Friedrichshafen on Thursday, 24th of September 2009. Find here an
attempt to a translation from the Museums Newsletter
<http://www.zeppelin-museum.de/1142.0.html#Donnerstagabend> :
Flight physics for beginners

Lecture by Dipl.-Ing. Johannes Eissing, ZLT Zeppelin Luftschifftechnik

What actually is flight physics, what does a flight physics engineer do,
and what is the difference between airships and airplanes? The talk
addresses the technically interested audience, but no special expertise
is necessary. The flight physics tasks within certification and
operation of airships are explained. Aerodynamics, flight mechanics and
aerostatics are illuminated by various models employed in an attempt to
tame a challenging subject.

Admission is free.    (Presentation will be in German)



[Non-text portions of this message have been removed]

Thanks for the announcement Johannes,
I want to add one more thing. I am always looking for new Ideas to add
to the generator and for bug reports. So please register at
http://bugs.airshipworld.info/ and file bug reports as well as new
feature requests.

Regards

Andreas

Editor of Airshipworld
--------------------------------------------------------
Visit the Airshipworld Blog at
http://airshipworld.blogspot.com
--------------------------------------------------------



On Tue, Aug 18, 2009 at 11:37 PM, Johannes
Eissing<johannes.eissing@...> wrote:
>
>
> Hi all,
>
> Andreas uploaded the new version of the Series 58 profile generator,
> see:
> http://www.airshipworld.info/software/2009/08/generator-v06-available/
> <http://www.airshipworld.info/software/2009/08/generator-v06-available/>
> It features computation of the centre of buoyancy, surface coefficient,
> polynomial coefficients plus several further improvements. You can
> download the java jar file here
>
> http://www.airshipworld.info/software/wp-content/uploads/2009/08/airship\
> worldprofilegenerator-v06.jar
> <http://www.airshipworld.info/software/wp-content/uploads/2009/08/airshi\
> pworldprofilegenerator-v06.jar>
>
> My computer prefered to rename the jar filt to a zip file, so I had to
> rename it manually, but as default it should work without problems.
> Please dont hesitate to post questions.
>
> Best regards and enjoy,
>
> Johannes
>
> --- In rc_airship_regatta@yahoogroups.com, "Johannes Eissing"
>
> <johannes.eissing@...> wrote:
>>
>> Andreas, great!
>> I had a little problem running the jar file, since windows made it a
>> zip- file when I downloaded it. So I changed the extension manually
>> from '.zip' to '.jar' and then it worked.
>> One point: The parameter 'L2D' should read 'Length to Diameter Ratio'
>> or better 'Slenderness Ratio', while it's now 'dimensionless bow
>> radius' due to a copy paste mishap I guess.
>> I think it's a most valuable tool :o)
>> Best, Johannes
>>
>> --- In rc_airship_regatta@yahoogroups.com, "Andreas Grunewald"
>> airshipworld@ wrote:
>> >
>> > Hello everybody,
>> > you may have heard that Johannes and I teamed up to build a nice
>> > little application callled the Gertler Series 58 Generator. I have
>> > written about it on the Airshipworld Development Blog at
>> > http://www.airshipworld.info/software/ before and now I am proud to
>> > announce the first preview version.
>> > It is available for download right now at
>> > http://www.airshipworld.info/software/2008/08/generator-version-05-
>> download/
>> >
>> > Please have a look at it and leave you comments either on the Blog
>> > post or as a reply to this Email. It's the first application that is
>> > released by Airshipworld but it wont be the last.
>> > Let your ideas run free, if you can imagine it we can build it.
>> >
>> > Have a good night and happy generating envelope profiles.
>> >
>> > Regards
>> >
>> > Andreas G
>> > --
>> > Editor of Airshipworld
>> > --------------------------------------------------------
>> > Visit the Airshipworld Blog at
>> > http://airshipworld.blogspot.com
>> > --------------------------------------------------------
>> >
>>
>
> [Non-text portions of this message have been removed]
>
>

Hi all,

Andreas uploaded the new version of the Series 58 profile generator,
see:
http://www.airshipworld.info/software/2009/08/generator-v06-available/
<http://www.airshipworld.info/software/2009/08/generator-v06-available/>
It features computation of the centre of buoyancy, surface coefficient,
polynomial coefficients plus several further improvements. You can
download the java jar file  here

http://www.airshipworld.info/software/wp-content/uploads/2009/08/airship\
worldprofilegenerator-v06.jar
<http://www.airshipworld.info/software/wp-content/uploads/2009/08/airshi\
pworldprofilegenerator-v06.jar>

My computer prefered to rename the jar filt to a zip file, so I had to
rename it manually, but as default it should work without problems.
Please dont hesitate to post questions.

Best regards and enjoy,

Johannes


--- In rc_airship_regatta@yahoogroups.com, "Johannes Eissing"
<johannes.eissing@...> wrote:
>
> Andreas, great!
> I had a little problem running the jar file, since windows made it a
> zip- file when I downloaded it. So I changed the extension manually
> from '.zip' to '.jar' and then it worked.
> One point: The parameter 'L2D' should read 'Length to Diameter Ratio'
> or better 'Slenderness Ratio', while it's now 'dimensionless bow
> radius' due to a copy paste mishap I guess.
> I think it's a most valuable tool :o)
> Best, Johannes
>
> --- In rc_airship_regatta@yahoogroups.com, "Andreas Grunewald"
> airshipworld@ wrote:
> >
> > Hello everybody,
> > you may have heard that Johannes and I teamed up to build a nice
> > little application callled the Gertler Series 58 Generator. I have
> > written about it on the Airshipworld Development Blog at
> > http://www.airshipworld.info/software/ before and now I am proud to
> > announce the first preview version.
> > It is available for download right now at
> > http://www.airshipworld.info/software/2008/08/generator-version-05-
> download/
> >
> > Please have a look at it and leave you comments either on the Blog
> > post or as a reply to this Email. It's the first application that is
> > released by Airshipworld but it wont be the last.
> > Let your ideas run free, if you can imagine it we can build it.
> >
> > Have a good night and happy generating envelope profiles.
> >
> > Regards
> >
> > Andreas G
> > --
> > Editor of Airshipworld
> > --------------------------------------------------------
> > Visit the Airshipworld Blog at
> > http://airshipworld.blogspot.com
> > --------------------------------------------------------
> >
>




[Non-text portions of this message have been removed]

Hi all again,

Lars argued a duration flight wouldn't be that interesting for spectators, and
that pushing LiPo batteries to the limit could even be dangerous. A solution for
the LiPo problem could be to force the use of particular batteries and have a
"Duracell Bunny" competition. I tried this years back with no success, see
http://tech.groups.yahoo.com/group/rc_airship_regatta/surveys
You all are just individualists, and it's good that way ;o)

Lars proposed to place a window or frame between the pylons. This would force a
more precise flight and allow for more accurate time measurement. The window
could be e.g. 2 times two meters.

Neat idea, I already hear the crowd yelling "Olé!!!" ;o) Would be  problematic
for the bigger ships, though.

The last thought leads me to a proposal I came up with again, when the hot air
ships were discussed. It would be more comparative not to scale the time
measured, but the parcours itself, see
http://tech.groups.yahoo.com/group/rc_airship_regatta/message/593
The scale factor is determined as usual by (length times width times height) to
the (1/3) power. But instead of computing a time scale factor by scale to the
1/2 power, the parcours itself is scaled. This would allow even full scale
airships to compete.

Let's see, The N07 is 75m long, 19.5m wide and 17.4m high. Makes a box volume of
75mx19.5mx17.4m=25448m^3
and a scale factor of
[(25448.5m^3)/(1m^3)]^(1/3)=29.41
so the distance between the pylons would be
25m*29.41=735.3m
Sportive, but possible ;o)

I'll put this in the regulations for the next race, presumably in June 2010. So
Dominik, Kyle, ISO Luftschiffer, get your hot air bags ready until then!!

Best, Johannes

--- In rc_airship_regatta@yahoogroups.com, "larspaasche" <lars.paasche@...>
wrote:
>
> Hallo Luftschiffler,
>
> die Idee eines Dauerflugs finde ich für das Publikum nicht interessant und
glaube bezüglich des Zeitfaktors, dass das keine so
> gute Idee ist. Ein anderes Problem sehe ich in der Tiefenentladung der
Lipozellen, ich könnte mir sehr gut vorstellen das bei einem solchen Wettbewerb
die Sicherungen für die Tiefenentladung entfernt werden.
>
> Ich hätte da aber noch einen anderen Vorschlag.
> Ich glaube es wäre eine gute Idee ein Fenster (Größe 2 m x 2 m)
> in die Mitte des Parcours aufzustellen, das bei jeder Runde durchflogen werden
muss.
> Hier ist es auch einfach eine Zeitmessung beim Durchfliegen des Fensters zu
starten.
>
> Viele Grüße
> Lars
>
>
> --- In rc_airship_regatta@yahoogroups.com, "erichder5te" <ErichFink@> wrote:
> >
> > Hallo Luftschiffer,
> >
> > ich hatte mit Phillip beim letzten Luftschiffrennen darüber geredet, daß man
mal einen Dauer "flug" Wettbewerb veranstalten müßte.
> > Hintergrund war die idee, daß man so besser eine Aussage über die
Gesamteffizienz der Konfiguration treffen könnte.
> >
> > Ich würde dazu vorschlagen die "Transportleistung" mit der Akkuleistung zu
vergleichen.
> >
> > Die Transportleistung oder ähnliches könnte aus dem Boxmaß, der
zurückgelegten Strecke (Runden) und der gemessenen Zeit bestimmt werden.
Gefahren werden soviele Runden wie möglich...
> >
> > Akkuleistung wird raufgeguckt was auf dem Akku steht.
> >
> > Ich denke der zusätzliche Aufwand wäre gering. Es könnten vielleicht auch
mehrere Luftschiffe gleichzeitig fahren.
> >
> > Was haltet ihr grundsätzlich davon?
> >
> > Über die genaue verrechnung bin ich natürlich für verbesserungs Vorschläge
offen
> >
> > gruss derich
> >
>

Hi all,

Erich proposed a new way to evaluate the overall efficiency of an airship
concept. Idea is to compare the 'transport power' and 'battery power'.

It's a question of units here. A battery is mainly described by its capacity in
Ampere hours. This is comparable to the physics term 'work'. 'Power' is 'work'
per time. So it's not really comparable. I Think there are two ways to compare
the transport performance:

1.) power
in ADA058237 'Assessment of Selected Lighter-Than-Air Vehicles for Mission Tasks
of the U.S. Coast Guard' Transport power is defined and investigated as
'productivity', being payload times speed. This is kind of a mass flow. To make
it the same dimension as power, one can multiply it by acceleration due to
gravity. This way you can compare transport power to engine shaft power to get
an idea about propulsive efficiency. Our regulations are doing this.

2.) work
Work is e.g. force times distance. A force can be for example the weight of
payload or maybe drag. Best efficiency at a given payload (or battery weight)
would be maximum distance traveled. Kind of galon milage. But one should ask the
customer for a prospective transport servive, if he is willing to wait ages for
the delivery. If a ship is twice as slow as a competing ship, you would need two
ships to serve a given transport task, measured in e.g. tons miles PER YEAR.

So my feeling is the existing rules are serving the efficiency thought quite
well. The more efficient the ship, the smaller can the battery be chosen, the
bigger again the engine and the faster the ship...

Best, Johannes

--- In rc_airship_regatta@yahoogroups.com, "erichder5te" <ErichFink@...> wrote:
>
> Hallo Luftschiffer,
>
> ich hatte mit Phillip beim letzten Luftschiffrennen darüber geredet, daß man
mal einen Dauer "flug" Wettbewerb veranstalten müßte.
> Hintergrund war die idee, daß man so besser eine Aussage über die
Gesamteffizienz der Konfiguration treffen könnte.
>
> Ich würde dazu vorschlagen die "Transportleistung" mit der Akkuleistung zu
vergleichen.
>
> Die Transportleistung oder ähnliches könnte aus dem Boxmaß, der zurückgelegten
Strecke (Runden) und der gemessenen Zeit bestimmt werden. Gefahren werden
soviele Runden wie möglich...
>
> Akkuleistung wird raufgeguckt was auf dem Akku steht.
>
> Ich denke der zusätzliche Aufwand wäre gering. Es könnten vielleicht auch
mehrere Luftschiffe gleichzeitig fahren.
>
> Was haltet ihr grundsätzlich davon?
>
> Über die genaue verrechnung bin ich natürlich für verbesserungs Vorschläge
offen
>
> gruss derich
>

Hallo Luftschiffler,

die Idee eines Dauerflugs finde ich für das Publikum nicht interessant und
glaube bezüglich des Zeitfaktors, dass das keine so
gute Idee ist. Ein anderes Problem sehe ich in der Tiefenentladung der
Lipozellen, ich könnte mir sehr gut vorstellen das bei einem solchen Wettbewerb
die Sicherungen für die Tiefenentladung entfernt werden.

Ich hätte da aber noch einen anderen Vorschlag.
Ich glaube es wäre eine gute Idee ein Fenster (Größe 2 m x 2 m)
in die Mitte des Parcours aufzustellen, das bei jeder Runde durchflogen werden
muss.
Hier ist es auch einfach eine Zeitmessung beim Durchfliegen des Fensters zu
starten.

Viele Grüße
Lars


--- In rc_airship_regatta@yahoogroups.com, "erichder5te" <ErichFink@...> wrote:
>
> Hallo Luftschiffer,
>
> ich hatte mit Phillip beim letzten Luftschiffrennen darüber geredet, daß man
mal einen Dauer "flug" Wettbewerb veranstalten müßte.
> Hintergrund war die idee, daß man so besser eine Aussage über die
Gesamteffizienz der Konfiguration treffen könnte.
>
> Ich würde dazu vorschlagen die "Transportleistung" mit der Akkuleistung zu
vergleichen.
>
> Die Transportleistung oder ähnliches könnte aus dem Boxmaß, der zurückgelegten
Strecke (Runden) und der gemessenen Zeit bestimmt werden. Gefahren werden
soviele Runden wie möglich...
>
> Akkuleistung wird raufgeguckt was auf dem Akku steht.
>
> Ich denke der zusätzliche Aufwand wäre gering. Es könnten vielleicht auch
mehrere Luftschiffe gleichzeitig fahren.
>
> Was haltet ihr grundsätzlich davon?
>
> Über die genaue verrechnung bin ich natürlich für verbesserungs Vorschläge
offen
>
> gruss derich
>

Hallo Luftschiffer,

ich hatte mit Phillip beim letzten Luftschiffrennen darüber geredet, daß man mal
einen Dauer "flug" Wettbewerb veranstalten müßte.
Hintergrund war die idee, daß man so besser eine Aussage über die
Gesamteffizienz der Konfiguration treffen könnte.

Ich würde dazu vorschlagen die "Transportleistung" mit der Akkuleistung zu
vergleichen.

Die Transportleistung oder ähnliches könnte aus dem Boxmaß, der zurückgelegten
Strecke (Runden) und der gemessenen Zeit bestimmt werden. Gefahren werden
soviele Runden wie möglich...

Akkuleistung wird raufgeguckt was auf dem Akku steht.

Ich denke der zusätzliche Aufwand wäre gering. Es könnten vielleicht auch
mehrere Luftschiffe gleichzeitig fahren.

Was haltet ihr grundsätzlich davon?

Über die genaue verrechnung bin ich natürlich für verbesserungs Vorschläge offen

gruss derich

Hallo Luftschiffer, (english below)

Die Lange Nacht der Lufschiffregatta und Wissenschaften ist nun schon über eine
Woche her. Alle Luftschiff sind ordentlich in ihrem Hanger, Koffer oder Kiste
verstaut und die Piloten und Mitwirkenden ausgeschlafen.

Ein ganz großes Dankeschön an alle die dieses Jahr mit dabei waren, die Piloten,
die Helfer im Vorder- und Hintergrund und die Verantwortlichen im Haus des
Bauens / der Peter-Behrens-Halle, die uns jedes Jahr freundlich unterstützen und
ihren Luftraum uneingeschränkt zur Verfügung stellen.
Es gab wie immer viel zu tun, aber ich denke wir alle Blicken auf ein gelungenes
Event zurück.

Für alle die diesen Tag noch einmal Revue passieren lassen wollen, haben wir von
der PW IsoLuftschiff einige Impressionen auf unsere Homepage zusammengestellt
(wird sicher noch mehr) .
Und natürlich, für alle die schon gespannt darauf warten, alle Zeiten und
Ergebnisse des großen Wettstreits der Luftschiffe sind nun Online!  (Alle
angaben ohne Gewähr, Unstimmigkeiten bitte an m.zobel@...)

Also besucht bitte unsere Seite:

www.isoluftschiff.de   -->  Aktuell


Auswertung des Rennens findet ihr auch hier im Forum,
http://tech.groups.yahoo.com/group/rc_airship_regatta/files/Berlin/

Rennauswertung LNDW2009.pdf    als pdf kurz und knapp
http://f1.grp.yahoofs.com/v1/EApBSuDwuZJ8Vk3OSR7_AJQLbBqxpVEel2aRx-zazhiDthuwdoX\
CCrCRMGhLlDGe4Dnxp3NFsnpknAHIy09w4c_3EYvpAV0/Berlin/Rennauswertung%20LNDW2009.pd\
f

oder ganz ausfürhlich als xls
Rennwertung_LNDW2009.xls



Viele Grüße und bis zum nächsten Mal ;-)
die Projektwerkstatt IsoLuftschiff




(english)
Dear Airskippers,

please check out our homepage with new stuff form Airshiprace in Berlin.
Pictures, Movies and a lot more you can find here:

www.isolufschiff.de  -->  Akutell   (sorry only available in german language)

You can find the results of the race also here:
http://tech.groups.yahoo.com/group/rc_airship_regatta/files/Berlin/

Rennauswertung LNDW2009.pdf    short version with main results
http://f1.grp.yahoofs.com/v1/EApBSuDwuZJ8Vk3OSR7_AJQLbBqxpVEel2aRx-zazhiDthuwdoX\
CCrCRMGhLlDGe4Dnxp3NFsnpknAHIy09w4c_3EYvpAV0/Berlin/Rennauswertung%20LNDW2009.pd\
f

or the complete analysis as xls in the same folder.
Rennwertung_LNDW2009.xls


with kind regards from Berlin,
the PW IsoLuftschiff

Hallö,

es wurden die ersten Videos von der LNDW 2009 hochgeladen:
here is a link for the fresh uploaded videos of the lndw2009:

http://www.youtube.com/watch?v=_dWBBM4lnpQ

gruss Erich

Hi Pack,

Philip, Gerhard, Tina and I made the trip to Torino for the FAI WAG (Fédération
Aéronautique Internationale World Air Games). Because we were so few, we had no
real regatta, but a demo race. We got two slots of 20 minutes each, where we
demonstrated the race and some freestyle aerobatics ;o) Fabrizio Ceccarini
introduced the airships to the audience. All in all I think it was success, and
good fun by the way.

I think we will see some nice photos and videos soon.

Best, Johannes

Hi Kyle,
I hope there will be more RC thermal airships around. But I am  in this
project  for  some years  (of course with  many interuptions ) and have
seen that many problems have to be solved. So a internet group or
homepage could help.
  I made a rudder from polyurethane foam (as used for outdoor matresses),
it is elastic and strong enough to survive the ship sitting in it.

  I hope we can see  the performance of the Isoluftschiff from Berlin
quite soon.  Of course  design and building is much more complicated.
But I am shure it is worth to experience  and it is interesting for hot air
balloons as
well.
I fear using solar power makes no sense for a small ship as the
surface is to large and the input is pretty small.
Cheers
Dominik



Kyle Kepley schrieb:
>
>
> Hi Dominik,
>
> It seems even today most innovation in airships still comes from Germany!
> It is good to see other people building RC thermal blimps, maybe one day
> they will become more common. I think once the basic problems are
> identified with a choice of common solutions outlined, the new builder
> will
> have an easier time getting started with less risk of costly
> surprises. If
> I can ever get some free time I'd like to make a website that promotes RC
> thermal blimps. My problem is that I always have too many projects going
> to start something like that.
>
> I had trouble with my fin spars breaking during inflation when the weight
> of the blimp is sitting on them at an angle. I tried several different
> rod
> types such as wooden dowel rods, fiberglass tubes, carbon fiber tubes
> but I
> found the best strength to weight ratio came from bamboo rods. Bamboo was
> the lightest, cheapest and would not break when bent extensively. The
> only
> disadvantage is the irregularity in diameter and finding a perfectly
> straight piece, but it is so cheap you can buy a bundle of tomato stakes
> and there are usually enough straight ones to work with.
>
> My rudder is a fabric pocket sewn onto the trailing edge of the bottom
> fin
> into which a piece of foam-core poster board is inserted to make it
> rigid.
> I haven't tested it yet, but I imagine it would be hard to damage it.
> Even
> if the insert got bent, replacing it would be cheap and easy. I've been
> waiting for almost two months for new electric motors to arrive before I
> can proceed with more flight tests.
>
> I think insulating the envelope would carry a pretty big weight
> penalty and
> increase the fabrication time considerably. A double walled envelope
> would
> probably be the most practical, using an air layer as the insulator. A
> black inner envelope with a clear plastic outer envelope could use solar
> heating to offset heat loss as well, but then you get an ugly blimp
> with no
> color choices. Since an RC blimp only flies within the sight of the pilot
> and can be easily flown back to its starting point, I think the simple
> solution is to just keep a bunch of fuel tanks on the ground and then
> refuel it every 15 minutes or so with a tank-swap.
>
> -Kyle
>
> [Non-text portions of this message have been removed]
>
>

> And I hope Hannes allows us to use this group for thermal ships as well.

Dominik, off course I do. This could become a new RC Airship Regatta Class.
Since hot air blimps somehow exceed 1 cbm boxvolume, and these are outdoor
ships, I'd propose to adopt special regulations for them.

If the distance between the pylons is scaled by the blockvolume to the one third
power, there would be no need for a penalty factor. Example: your hot air blimp
is 10m long, 2.5m high and 2.5m wide. The block volume would then be 10m x 2.5m
x 2.5m = 62.5m^3. The scale factor would be 62.5^(1/3)=3.97. The distance
between the pylons would be 25m*3.97=99.2m.

What ya think?
Best, Johannes

--- In rc_airship_regatta@yahoogroups.com, Dominik Baumüller
<dominik.baumueller@...> wrote:
>
> Hi Kyle,
> I tried a rudder in the fin as well. But the height adjustment of a
> unmanned thermal airship is not easy (and I know how to fly a real
> balloon). Due to the high inertial mass of the air I made a lot of hard
> landings always destroying the rudder. So I prefer the solution with
> vectored thrust as it allows good vertical control as well. I fly the
> ship a bit heavy and use the thrust for climbing. Now I need some
> training to get full pitch control. I have two burners and a bulkhead,
> but I need to get used to it and of course I am nervous as well trying
> not  to burn the new envelope.
>
>
> And I hope Hannes allows us to use this group for thermal ships as well.
> But there are two ships flying and at least another one is under
> construction (www.isoluftschiff.de) so we have enough ships for a
> regatta in the near future.
> Dominik
>
> Kyle Kepley schrieb:
> >
> >
> > Oh, I forgot to mention that I have added a rudder to the lower fin on
> > my blimp since those pictures were taken. Originally I thought just
> > having two motors would be able to generate enough torque to turn the
> > blimp when running only one motor, but there is not enough leverage
> > due to how close the motors are to the center of gravity. So now a
> > single rudder is used to turn. Pitch can be roughly controlled by
> > firing the front or back burner independently, since the blimp is
> > divided into two sections by a central bulkhead. Due to the amount of
> > money I have invested in this project I'm still too nervous to fly it
> > much above treetop level, so I plan to fly it mostly low and slow for
> > now, often with a tether. It's all electric powered, which is nice for
> > the ability to completely stop and restart the motors and is also
> > quiet, but electric does lower the run-time compared with gas motors
> > of equivelent weight. The gondola is designed to allow both the
> > batteries and the fuel cylinders to be quickly changed out in the
> > field without the use of tools. Each set of two propane tanks lasts me
> > about 15 minutes of flight. These are the cheap disposable camping
> > type cylinders that hold about a 500g of propane each, and are easily
> > refilled from a spare 10 gallon hot air balloon tank that I have. Thus
> > it is easily affordable to have a box of eight or ten fuel tanks on
> > the field to keep a flight going. The pressurization fan batteries
> > used to be the weak link that limited flying time, but I have recently
> > rebuilt those to minimize current draw and now they can run continuous
> > for an hour. As soon as my new main drive motors arrive I'll be ready
> > for more testing (my original Turnigy motors broke due to poor quality
> > bearings).
> >
> > -Kyle
> >
> > ----------------------------------------
> >
> > From: "Dominik Baumüller" <dominik.baumueller@...
> > <mailto:dominik.baumueller%40beyond-gravity.com>>
> > Sent: Sunday, June 07, 2009 4:49 PM
> > To: rc_airship_regatta@yahoogroups.com
> > <mailto:rc_airship_regatta%40yahoogroups.com>
> > Subject: Re: [rc_airship_regatta] For the hot air blimper amongst us
> >
> > .
> >
> > [Non-text portions of this message have been removed]
> >
> >
>
>
> --
> Dr. Dominik Baumüller
>
> beyond-gravity-group
> textile prototyping
> Pappenheimstr. 7 Rckg.
> D-80335 München
> fon/fax: +49-89-555411
> www.beyond-gravity.com
>

Hi Dominik,

It seems even today most innovation in airships still comes from Germany!
It is good to see other people building RC thermal blimps, maybe one day
they will become more common.  I think once the basic problems are
identified with a choice of common solutions outlined, the new builder will
have an easier time getting started with less risk of costly surprises.  If
I can ever get some free time I'd like to make a website that promotes RC
thermal blimps.  My problem is that I always have too many projects going
to start something like that.

I had trouble with my fin spars breaking during inflation when the weight
of the blimp is sitting on them at an angle.  I tried several different rod
types such as wooden dowel rods, fiberglass tubes, carbon fiber tubes but I
found the best strength to weight ratio came from bamboo rods.  Bamboo was
the lightest, cheapest and would not break when bent extensively.  The only
disadvantage is the irregularity in diameter and finding a perfectly
straight piece, but it is so cheap you can buy a bundle of tomato stakes
and there are usually enough straight ones to work with.

My rudder is a fabric pocket sewn onto the trailing edge of the bottom fin
into which a piece of foam-core poster board is inserted to make it rigid.
I haven't tested it yet, but I imagine it would be hard to damage it.  Even
if the insert got bent, replacing it would be cheap and easy.  I've been
waiting for almost two months for new electric motors to arrive before I
can proceed with more flight tests.

I think insulating the envelope would carry a pretty big weight penalty and
increase the fabrication time considerably.  A double walled envelope would
probably be the most practical, using an air layer as the insulator.  A
black inner envelope with a clear plastic outer envelope could use solar
heating to offset heat loss as well, but then you get an ugly blimp with no
color choices.  Since an RC blimp only flies within the sight of the pilot
and can be easily flown back to its starting point, I think the simple
solution is to just keep a bunch of fuel tanks on the ground and then
refuel it every 15 minutes or so with a tank-swap.

-Kyle




[Non-text portions of this message have been removed]

Hi Kyle,
I tried a rudder in the fin as well. But the height adjustment of a
unmanned thermal airship is not easy (and I know how to fly a real
balloon). Due to the high inertial mass of the air I made a lot of hard
landings always destroying the rudder. So I prefer the solution with
vectored thrust as it allows good vertical control as well. I fly the
ship a bit heavy and use the thrust for climbing. Now I need some
training to get full pitch control. I have two burners and a bulkhead,
but I need to get used to it and of course I am nervous as well trying
not  to burn the new envelope.


And I hope Hannes allows us to use this group for thermal ships as well.
But there are two ships flying and at least another one is under
construction (www.isoluftschiff.de) so we have enough ships for a
regatta in the near future.
Dominik

Kyle Kepley schrieb:
>
>
> Oh, I forgot to mention that I have added a rudder to the lower fin on
> my blimp since those pictures were taken. Originally I thought just
> having two motors would be able to generate enough torque to turn the
> blimp when running only one motor, but there is not enough leverage
> due to how close the motors are to the center of gravity. So now a
> single rudder is used to turn. Pitch can be roughly controlled by
> firing the front or back burner independently, since the blimp is
> divided into two sections by a central bulkhead. Due to the amount of
> money I have invested in this project I'm still too nervous to fly it
> much above treetop level, so I plan to fly it mostly low and slow for
> now, often with a tether. It's all electric powered, which is nice for
> the ability to completely stop and restart the motors and is also
> quiet, but electric does lower the run-time compared with gas motors
> of equivelent weight. The gondola is designed to allow both the
> batteries and the fuel cylinders to be quickly changed out in the
> field without the use of tools. Each set of two propane tanks lasts me
> about 15 minutes of flight. These are the cheap disposable camping
> type cylinders that hold about a 500g of propane each, and are easily
> refilled from a spare 10 gallon hot air balloon tank that I have. Thus
> it is easily affordable to have a box of eight or ten fuel tanks on
> the field to keep a flight going. The pressurization fan batteries
> used to be the weak link that limited flying time, but I have recently
> rebuilt those to minimize current draw and now they can run continuous
> for an hour. As soon as my new main drive motors arrive I'll be ready
> for more testing (my original Turnigy motors broke due to poor quality
> bearings).
>
> -Kyle
>
> ----------------------------------------
>
> From: "Dominik Baumüller" <dominik.baumueller@...
> <mailto:dominik.baumueller%40beyond-gravity.com>>
> Sent: Sunday, June 07, 2009 4:49 PM
> To: rc_airship_regatta@yahoogroups.com
> <mailto:rc_airship_regatta%40yahoogroups.com>
> Subject: Re: [rc_airship_regatta] For the hot air blimper amongst us
>
> .
>
> [Non-text portions of this message have been removed]
>
>


--
Dr. Dominik Baumüller

beyond-gravity-group
textile prototyping
Pappenheimstr. 7 Rckg.
D-80335 München
fon/fax: +49-89-555411
www.beyond-gravity.com

Hallo Michael,
ich hatte vor einigen Jahren Kontakt zum Erbauer des Gefa-Modelles, das
ist ihm aber wohl etwas über den Kopf gewachsen.
Schön, daß es doch noch in die Luft kommen kann und so tut sich ja zur
Zeit wirklich was in der Szene.
Meine Hülle hat auch ein Überdruckventil nach Gefa-Muster, es ist aber
etwas zu klein geraten. Ich habe keine Probleme mit Flame-outs, die
Brenner saugen genug Luft an. Zusätzlich habe ich einen Schlauch im
Propellerstrom, um den Hüllendruck  zu erhalten.
Natürlich wäre es eleganter und sauberer, mit Elektromotoren zu arbeiten,
aber die Akkukosten haben bisher noch abgeschreckt. In der nächsten
Ausbaustufe kommt das aber (natürlich neben einer Wärmedämmung  der
Hülle, denn der Gasverbrauch ist erheblich)
Grüße
Dominik

Michael Bölling schrieb:
>
>
> Hi Dominik
>
> sieht ja sehr gut aus das Luftschiff.
> Bei den großen Luftschiffen gab früher immer wieder Flame Outs, d.h.
> irgendwann war der Sauerstoff verbraucht und der Brenner ging aus,
> aber seit ein Ventilator permanent Luft zum Brenner bläst funktioniert
> das einwandfrei. Außerdem gibt es vorne Ventile mit Gummibändern über
> die der Druck eingestellt werden kann. Damit wird auch immer frische
> Luft reingespült. Vielleicht wär das auch ne Idee für dein
> Brennersystem, oder saugt der Brenner durch das Rohr genug Luft an?
> Wir haben auch noch eine Gefa Hülle zu der wir die Gondel noch fertig
> machen wollen. Der Besitzer ist leider verstorben und wir wollen das
> Projekt zu seinem Gedenken vollenden. Vermutlich nehmen wir Elektro
> Motoren, das hat auch Mucky Busemeyer empfohlen weil man dadurch
> vielen Problemen aus dem Weg gehen kann.
>
>


--
Dr. Dominik Baumüller

beyond-gravity-group
textile prototyping
Pappenheimstr. 7 Rckg.
D-80335 München
fon/fax: +49-89-555411
www.beyond-gravity.com

Oh, I forgot to mention that I have added a rudder to the lower fin on my blimp
since those pictures were taken.  Originally I thought just having two motors
would be able to generate enough torque to turn the blimp when running only one
motor, but there is not enough leverage due to how close the motors are to the
center of gravity.  So now a single rudder is used to turn.  Pitch can be
roughly controlled by firing the front or back burner independently, since the
blimp is divided into two sections by a central bulkhead.  Due to the amount of
money I have invested in this project I'm still too nervous to fly it much above
treetop level, so I plan to fly it mostly low and slow for now, often with a
tether. It's all electric powered, which is nice for the ability to completely
stop and restart the motors and is also quiet, but electric does lower the
run-time compared with gas motors of equivelent weight.  The gondola is designed
to allow both the batteries and the fuel cylinders to be quickly changed out in
the field without the use of tools.  Each set of two propane tanks lasts me
about 15 minutes of flight.  These are the cheap disposable camping type
cylinders that hold about a 500g of propane each, and are easily refilled from a
spare 10 gallon hot air balloon tank that I have.  Thus it is easily affordable
to have a box of eight or ten fuel tanks on the field to keep a flight going. 
The pressurization fan batteries used to be the weak link that limited flying
time, but I have recently rebuilt those to minimize current draw and now they
can run continuous for an hour.  As soon as my new main drive motors arrive I'll
be ready for more testing (my original Turnigy motors broke due to poor quality
bearings).

-Kyle

----------------------------------------

From: "Dominik Baumüller" <dominik.baumueller@...>
Sent: Sunday, June 07, 2009 4:49 PM
To: rc_airship_regatta@yahoogroups.com
Subject: Re: [rc_airship_regatta] For the hot air blimper amongst us

.






[Non-text portions of this message have been removed]

Hi Dominik,

Thanks for posting the additional pictures. I had always wanted to see more
details about the beyond-gravity thermal blimp but could not see much from the
tiny video of the yellow one.  Is this your project? The blue one looks much
improved in the shape of the envelope and the fin design.  The steering is
innovative too, I never thought about moving the gondola forward for better
leverage against the center of gravity and then have a pivoting fan.  On the one
hand it removes the complexity of a rudder or dual motors, with the penalty
being the need for a second gondola (the rear burner).

Building a thermal airship is indeed more challenging than a gas blimp.  I've
built gas blimps in the past and they were much easier.  Just getting the burner
to work reliably was a lot of work for me, then there are the issues of fighting
the run-away pitch problem, pressurization during flight, feeding oxygen to the
burner and expelling all the CO2 generated that collects at the bottom of the
envelope (adding to the burner flame-out problem).  The nice thing about thermal
airships is there's not much of a cost penalty for making large size models the
way there is for helium filled blimps, and you can pack them neatly away when
not flying them without dumping expensive gas each time.

I started my blimp project merely as a sewing project to learn how to build hot
air balloon envelopes without making mistakes on a real hot air balloon.  Then I
got obsessed with making the thing actually fly.  My first one was too small and
under powered, but the second one turned out good.  It's slightly smaller than
yours at 12 meters in length, 82 cubic meters and a fineness ratio of 3.3 to 1.

I see a balloon basket in one of the pictures, are you a balloon pilot also?  I
got my hot air balloon pilot license last summer and recently bought a used
Aerostar Aurora 54K system that is a lot of fun to fly!

-Kyle Kepley

----------------------------------------

From: "Dominik Baumüller" <dominik.baumueller@...>
Sent: Sunday, June 07, 2009 4:49 PM
To: rc_airship_regatta@yahoogroups.com
Subject: Re: [rc_airship_regatta] For the hot air blimper amongst us

Hi Kyle,
the blue ship is the one from beyond-gravity.com indeed. The new
envelope , a Gertler Shape (4154) with a slenderness ratio of 3.7 hat
two gondolas, the front gondola is carrying the engine (tiltable in two
axes) and one burner, the aft gondola is carrying another burner and
the gas tanks.Well, a thermal RC-ship it is pretty complex- and heat
insulation is not jet included!
Lenght is 14.5 m, volume is 120 m3.
Right now I am dealing with the pitch control.
I have put some more pictures at
http://groups.yahoo.com/group/rc_airship_regatta/photos/album/1699907336/pic/lis\
t
<http://groups.yahoo.com/group/rc_airship_regatta/photos/album/1699907336/pic/li\
st>

The picture of the Gefa-Blimp is from a conference proceeding
(DGLR-Proceedings 91-02 ,Hot Air Aerostatic Vehicle Technology, Aachen
1991)
It is a tethered system without propulsion. As far as I know they are no
longer active in this field.

Your project at rc-groups looks very interesting, what about your yaw
and pitch-control?

Blue skies
Dominik

Hallo Kyle
das blaue Schiff ist das von beyond-gravity. Die neue Hülle, ein Gertler
4154 hat zwei Gondeln, die vordere trägt den zweiachsig drehbaren Motor
und einen Brenner, die hintere trägt einen weiteren Brenner und den
Gasvorrat. In der Tat ist ein thermisches RC-Schiff ziemlich komplex,
zumal die Wärmedämmung noch nicht dabei ist!
Lange: 14,5 m, Volumen: 120m3.
Derzeit kämpfe ich mit der Nicksteuerung.
Ich hab ein paar weitere Bilder auf
http://groups.yahoo.com/group/rc_airship_regatta/photos/album/1699907336/pic/lis\
t
<http://groups.yahoo.com/group/rc_airship_regatta/photos/album/1699907336/pic/li\
st>
gelegt.
Dein Projekt sieht sehr interessant aus, was macht Deine Nick- und
Giersteuerung?

Blue skies
Dominik

Kyle Kepley schrieb:
>
>
> That blue one looks the new blimp "Leonardo" from the guys at
> beyond-gravity.com:
> http://www.beyond-gravity.com/leo.html
> <http://www.beyond-gravity.com/leo.html>
>
> I didn't even know that Gefa-Flug made small RC blimps. I couldn't
> find any information about GF 200 on their website.
>
> I couldn't find the picture of your new thermal airship in the photo
> area... could you link to the picture?
>
> Fully functional thermal blimps seem very rare. After lots of
> searching I've found four so far, including my own.
> Here's one made by the French several years back:
>
> http://www.mini-ballon-passion.com/videos/dirigeable.avi
> <http://www.mini-ballon-passion.com/videos/dirigeable.avi>
>
> -Kyle
>
> ----------------------------------------
>
> From: "Dominik Baumüller" <dominik.baumueller@...
> <mailto:dominik.baumueller%40beyond-gravity.com>>
> Sent: Sunday, June 07, 2009 8:04 AM
> To: rc_airship_regatta@yahoogroups.com
> <mailto:rc_airship_regatta%40yahoogroups.com>
> Subject: Re: [rc_airship_regatta] For the hot air blimper amongst us
>
> I would think this blimp is inspired (or even is one) of the Gefa-Flug
> GF 200
> captured balloons for aerial photography:
>
http://groups.yahoo.com/group/rc_airship_regatta/photos/album/1699907336/pic/lis\
t
>
<http://groups.yahoo.com/group/rc_airship_regatta/photos/album/1699907336/pic/li\
st>
>
> In the photo area you also can find a first picture of our new thermal
> airship, almost airborne..
>
> Dominik
>
> Kyle Kepley schrieb:
> >
> >
> > That actually looks like an RC hot air balloon that is just in the
> > shape of
> > a blimp, with no powered flight or control over direction.
> >
> > I've actually developed a true RC thermal airship, which is
> documented on
> > the following build log of the RC Groups forum:
> >
> >
> http://www.rcgroups.com/forums/showthread.php?t=1004918&highlight=hot+air+bl
> <http://www.rcgroups.com/forums/showthread.php?t=1004918&highlight=hot+air+bl>
> >
> <http://www.rcgroups.com/forums/showthread.php?t=1004918&highlight=hot+air+bl
>
<http://www.rcgroups.com/forums/showthread.php?t=1004918&highlight=hot+air+bl>>
> > imp
> >
> > There's actually two blimps documented there. The first blimp did not
> > have
> > enough power and was too small. The final functional blimp is seen on
> > page
> > 3 in that thread.
> >
> > -Kyle Kepley
> >
> > ----------------------------------------
> >
> > From: "Johannes Eissing" <johannes.eissing@...
> <mailto:johannes.eissing%40web.de>
> > <mailto:johannes.eissing%40web.de>>
> > Sent: Saturday, June 06, 2009 1:21 AM
> > To: rc_airship_regatta@yahoogroups.com
> <mailto:rc_airship_regatta%40yahoogroups.com>
> > <mailto:rc_airship_regatta%40yahoogroups.com>
> > Subject: [rc_airship_regatta] For the hot air blimper amongst us
> >
> > http://academic.emporia.edu/aberjame/airphoto/platform/blimp0.jpg
> <http://academic.emporia.edu/aberjame/airphoto/platform/blimp0.jpg>
> > <http://academic.emporia.edu/aberjame/airphoto/platform/blimp0.jpg
> <http://academic.emporia.edu/aberjame/airphoto/platform/blimp0.jpg>>
> > Cheers, Johannes
> >
> > [Non-text portions of this message have been removed]
> >
> >
>
> [Non-text portions of this message have been removed]
>
> [Non-text portions of this message have been removed]
>
>

--
Dr. Dominik Baumüller

beyond-gravity-group
textile prototyping
Pappenheimstr. 7 Rckg.
D-80335 München
fon/fax: +49-89-555411
www.beyond-gravity.com






[Non-text portions of this message have been removed]

Hi Dominik

sieht ja sehr gut aus das Luftschiff.
Bei den großen Luftschiffen gab früher immer wieder Flame Outs, d.h. irgendwann
war der Sauerstoff verbraucht und der Brenner ging aus, aber seit ein Ventilator
permanent Luft zum Brenner bläst funktioniert das einwandfrei. Außerdem gibt es
vorne Ventile mit Gummibändern über die der Druck eingestellt werden kann. Damit
wird auch immer frische Luft reingespült. Vielleicht wär das auch ne Idee für
dein Brennersystem, oder saugt der Brenner durch das Rohr genug Luft an?
Wir haben auch noch eine Gefa Hülle zu der wir die Gondel noch fertig machen
wollen. Der Besitzer ist leider verstorben und wir wollen das Projekt zu seinem
Gedenken vollenden. Vermutlich nehmen wir Elektro Motoren, das hat auch Mucky
Busemeyer empfohlen weil man dadurch vielen Problemen aus dem Weg gehen kann.