Re: [Flightgear-devel] An2 problems

[Joacim P. <no...@tu...>]

On Wed, 7 Mar 2007, Ron Jensen wrote:

> I hand massaged the pitch to 17/32 as in the original file, and I
> lowered the diameter from 141.7 to 132 because it wouldn't start with
> 141.7 as a diameter.

That (132in) is the correct diameter for the AV-2 propeller. (132 inches or
3.35 meters) Source: http://www.vectorsite.net/avan2.html

But there's supposed to be a gearbox between the engine and propeller on
the AN-2 versions with AV-2 propeller. And the AV-2 is not a constant speed
propeller, but a plain variable-pitch design. (ibid.)

I sent this patchlet to Yuri (the author) in november last year:
   an2/Engines/AV-2.xml:

   -  <minrpm>   400 </minrpm>
   -  <maxrpm>   2500 </maxrpm>
   +  <gearratio> 1.38 </gearratio>

   minrpm/maxrpm are for defining a constant speed propeller. (There is a bug
   in aeromatic.) For a manually variable pitch propeller, these should be
   left unset. And <gearratio> isn't generated by aeromatic either.

(I dont' know if Aeromatic has been fixed sinced that. Haven't checked.)

Then there were also some problems with hard-coded idle rpm limits in
JSBsim. This was discussed on the list when the aircraft model was
introduced last year (in november).