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
>