----- Original Message -----
From: "David Megginson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Wednesday, March 26, 2003 4:08 PM
Subject: re: [Jsbsim-devel] MSFS Aircrafts
> Erik Hofman writes:
>
> > How come whenever I release an aircraft for JSBSim, a few weeks
later I
> > see an anouncement on avsim.org that this type of aircraft will be
> > available to MSFS with a realistic flight model?
>
> At least one MSFS designer reads these lists and has been in touch
> with me about the 310 model (which I designed). I don't consider that
> a problem -- the person I corresponded with, at least, wanted to share
> ideas and feed fixes back into our data. In any case, it's worth
> remembering that we take many of our stability numbers from other
> people's work (like Roskam's).
I guess Roskam's S&C Vol 1 has quite a few good SD listings.
However, some AC may have dropped out of the more recent editions. I
accidentally ended up with S&C Vol 2, which has some curves showing Mach
variations with and without aeroelasticity included. The rest is on FB
control systems.
> I think that an application-independent public database of stability
> coefficients would be a worthwhile project in itself. It would be
> useful for FlightGear, XPlane, and MSFS, and we'd end up with a much
> bigger pool of contributors.
> Hmm. Maybe I'll start on that.
>
> David
I don't know how much can be explicitely set for X-Plane. Which is
claimed to 'calculate everything panel by panel'. FG and MSFS use
similar flight models, though one has to know how to convert when
non-linearities come into play.
Further, MSFS appears to only model slower AC well. Above 25,000
ft or so, especially at higher Mach numbers the code probably doesn't
step fast enough and some dampings have to be increased to keep an AC
stable. However, other SD's appear to apply quite well.
**** Regardless, a general database of Stability Derivatives and
other details would be quite useful. Powerplants also. Even basic
formulas. Also, Spreadsheets and programs to calculate performance
from basic elements. *******
One thing MS developers have is access to a lot of real pilots. Who
can at least give some idea if an AC 'feels right'. All the way to
747's. Further, they are good at scanning Flight Manuals that might be
hard to obtain otherwise. ;) We also have airline employees with
access for photographing cockpits etc. By hook and crook I also
managed to obtain a couple of Boeing Performance Engineering Manuals on
jet transports. One contains proprietary data on drags, lift, and
turbine matrices.
I'll point more of the engineers fooling with MSFS to
sci.aeronautics. One works for 'a big AC company' and has copied
several aerodynamics books from their library. Classics such as one by
Whittle on turbines.
Ron
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