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Attitude

F

Frippe123

Guest
Hello, i will try to explain my problem:

when flying at lower speeds around 300kts i need to have too much pitch attitude i think, the aircraft drops if i try level flight. the problem solves itself when going faster. is there anything i can do to fix this without changing too much? is my question unclear enough?

the sim is FSX

Thanks Fredrik
 
Frippe123 said:
Hello, i will try to explain my problem:

when flying at lower speeds around 300kts i need to have too much pitch attitude i think, the aircraft drops if i try level flight. the problem solves itself when going faster. is there anything i can do to fix this without changing too much? is my question unclear enough?

the sim is FSX

Thanks Fredrik
Click to expand...

Hi Fredrik,

The question is unclear enough. ;)

I'm not sure this will totally solve your problem, but here's a start. Set the cruising speed to around 300 kts (the speed where you want the aircraft to fly level), then go to the Airfoils tab and set 'Specified Pitch Attitude at Cruising Speed' to zero.

Also, the higher the value of Static Margin (on the Specs tab), the more trim required will change with air speed.
 
Ok, the cruising speed is set to 350 and airfoil is set to zero.
The static margin is 4%, it was 4 when i started this project and didnt understand what it was so i didnt change it.

Is 4% a high value? Is there "normal" values for certain types of aircraft?

Thanks Fredrik
 
oh oh one more: ive seen a chart for the real aircraft with cm vs mach at zero AoA, is there anything in fsx that calclates or even care about this, due to the book it was important how the aircraft behaved when passing the sound barrier or just before. fs has a f18 in the accelration pack but thats the only supersonic plane in fsx.

Thanks Fredrik
 
I changed the static margin to 0.1 and that really helped.

Thanks Fredrik
 
Static margin is a measure of how far aft the CoG can move before the pitch stability becomes negative.

Aircraft designed to carry passengers and cargo have high static margins; fly-by-wire modern fighters may be designed with negative static margin with the flight control system compensating for the aerodynamic instability.

Aircraft with positive static margin (i.e. positive stability) will return to trimmed flight when the aircraft is disturbed in pitch. Aircraft with zero static margin will tend to be neutral and need the pilot to apply elevator to return to the original pitch. With negative static margin the pitch change will continue after the disturbance is removed - pitch is still controllable but requires constant correction.

With AirWrench, very low static margins (0.1 to 1.0) will probably feel more like fly-by-wire controls. For airliners, numbers between 5 and 10 will probably feel more realistic.
 
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