Editing FDEs.....how do I learn?

[JBaymore]

I am wanting to fix some stuff in the flight model of an aircraft (Jon Murchison BAe 146-200).  

Where do I begin to learn how to do this?

best,

...................john

[G-Fire25]

I think you need the source file....

[Felix/FFDS]

To edit the FDE (i.e. aircraft.cfg and *.air files)  you should start off at avhistory.com  - the famous 1% spreadsheet, and/or Jerry Beckwith's  Air Wrench (modest payware) are excellent tools.

[JBaymore]

Thanks Felix.

I am finding that when I cut the throttles to flight idle at the TOD on my 146-200, that the descent IAS speed seems very slow with the aircraft in a rather nose high trim out when set at an appropriate FPM descent rate.  It should not be that nose high, which I think is affecting the airspeed with the extra drag.

best,

.......................john

[Brett_Henderson]

It's a geometric thing... many variables.. and changing one usually means changing a few others (In what will seem like illogical and unrealted ways ..lol )

For example, in your case you "might" want to try increasing parasitic drag.. which would mean reducing induced drag (to keep cruise airspeed right)... which might be followed by adjusting the wing incidence.

I remember flying an FS2004 BAE146 quite a bit.

[JBaymore]

[quote]I'd imagine that if you trimmed the nose down, the airspeed/descent might go too high.. That's were parasitc and induced drag come in. You'll probaly end up tinkering with thrust and and changing flap pitch/lift/drag too...

A single gaol in FDE editing ususally takes several paths..

[Brett_Henderson]

That will be a tricky one to resolve..  Probably a good one to cut your teeth on.  I'd offer to help, or do it for you, but I've not FS9 running right now.

You could cheat and just lower the location of the engines (start-up smoke will look funny) and then just fiddle with the incidence and/or make a mental note for the new trim settings...

If you go at this head on... you'll end up adjusting the paramters I've mentioned..  and likely;  tweak the heck out of the  "Flight Tuning" paragraph (you wanna keep that to a minimum... once you go too far there, your plane's flight envelope will barely resemble the airplane you started with)..

It's not as time consuming as 3D modeling, but FDEs can be just as challenging..

[Brett_Henderson]

One more important thought. If you are gonna do this, consider starting with a clean slate.

Go through the aircraft.cfg file to get a feel for it.. then go get all the EXACT numbers in front of you..

Most important are; Wing/stabilizer area/span, wing/control-surface apexes, engine locations, COG, flap-span, wing and tail incidences, and of course weights and MOIs.

To MSFS' credit.. if that "model" is accurate, you're way ahead of the game. Just tweaking specific parameters in an innacurate foundation, can leave you chasing your tail..