Models are very unstable

[HalH]

The models are very unstable. Is there a way to make them more stable ?

[flameboy479]

No.

[aeropal]

..

[HalH]

I am using Windows XP home edition with a JR transmitter. I am using the recommended version but I have tried two and the models act the same. I don't know how to change the graphics card.

[aeropal]

..

[ggunners]

I think you'll find that some models are unstable but folks may call them manueverable instead.

You can make the model more stable by reducing the control throws with one of the .par editors, reducing the size of the control surfaces or reducing the intertia moments for the X-pitch, Y-roll or Z-yaw axis in the MAIN section of the alpha 8.x .par file. You may also want to set exponential within the calibration section of the controls. Typically I set aileron as exponential for FMS on my computer.

-- ggunners

[HalH]

I don't have the faintest idea of how to access any files. You did note the inertia idea. I guess that best describes the problem. The models will continue to roll , for instance , even though the controls are nuetralized . It takes constant correction in all axis.

[flameboy479]

[Boonies Flyer]

I have realized this also, using the keys the airplane flies wierd, when you roll it keeps on rolling slightly. I am using a Real Flight R/C Simulator controller and it works great but the calibration is funky, like while flying the plane will spaze out funnyish. The trims dont work well either. I read on another forum that some guy is using a Flash 5 transmitter to fly, how would I hook that up to the computer? My neighor told me that you can make a plane more 3d'ish, that would be real nice because i have to work on hoovering before the annual fun fly comes around. Ggunners fill us in on this model modifiction stuff.

[ggunners]

For 3D, use one of the terrific 3D models available for download. is great!

Modifying .par files is easy with Mr. Masuoka's .par file editor called .

Make sure you create a .bak file of the .par before you start mucking around. That way, you can always go back later and delete your working .par.

Pitch, Roll and Yaw moments are related to aircraft weight a bit. Heavier models will and should be harder to move in the air.

Some very light coefficients with very little continuing travel would be like the FoamFly Frog:

0.2268 //Mass [Kg]
0.11 //Roll Inertia Moment Ixx [kg*m^2]
0.1 //Pitch Inertia Moment Iyy [kg*m^2]
0.5 //Yaw Inertia Moment Izz [kg*m^2]
-0.06 //Ixz [kg*m^2]

An airplane that is more neutrally rigged, like an acrobatic airplane, would require constant control and have a tendancy to keep on going in the direction it was headed.

Consider the Pitts

MAIN //allgemeine Daten

5.5 //Masse des Modells [kg]
0.42 //Trägheitsmoment um die Querachse (Ixx) [kg*m^2]
0.37 //Trägheitsmoment um die Längsachse (Iyy) [kg*m^2]
0.76 //Trägheitsmoment um die Hochachse (Izz) [kg*m^2]
-0.07 //Deviationsmoment (Ixz) [kg*m^2]

Of course, nothing is that simple. The moment of the airfoils actually change depending on the angle of attack of the wing and those moments are detailed in the POLAR section which is referenced by a POLAR number in the WING section of the .par file.

If the nose of your FMS model continues to move too much when using your elevator, then reduce the first coefficient (Ixx pitch), if the model tends to roll off the wing too easily, then adjust the second coefficient (Iyy roll) and then if the yawing movement i.e. back and forth of the nose at level flight continues on too much, reduce the third coefficient (Izz yaw).

That said, too stable a model may not be realistic. Some airplanes fall off the wing easier than others and should have a higher number in the roll (Iyy) coefficient. Or some planes when in a dive are almost impossible to pull up, consider increasing the pitch (Ixx) coefficient.

Hope that helps.

-- ggunners

[Boonies Flyer]

wow ggunners, when you start talking its like greek, i read all that and it flew like a mile over my head.

[orion1992-12]

I find that if your plane is unstable you are either being too rough with the countrols or are flying too fast. You can lower your speed by reducing your throttle. Just don't go too slow!

-orion1992-12

[ggunners]

One other thing to try is to check the [Exp] exponential box on the aileron control. It makes a big difference when flying low and slow.

-- ggunners

[hotrod]

where do i find it