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treblesum81

Aircraft Stability and Lateral Trimming

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Hi all,This is actually two separate issues that I was hoping to get some advice on. First, I've noticed a tendency of quite a few of my lighter aircraft have developed some stability problems lately which manifest themselves almost as if the aircraft is balancing on a knife edge with a difficult to control tendency to roll one way or another seemingly at random. Now I am a RL pilot, and as such fly with full realism and I am fully aware of P-Factor and other issues which might produce such movements legitimately, and I am almost sure that this are not the cause of this problem. One of my basis for this assumption is the fact that it happens at an speed and angle of attack, and in my experience, most of the forces that would cause consistent rolls / yaws in either direction fade away after about Vy + 10%-15%, yet I've found my aircraft rolling and/or yawing off all the way up to Vne.Personally I think this has to do with my flight controller setup, as all of this started once I upgraded from a Saitek Cyborg 3D to a Saitek X52 + Saitek Rudder Pedals. These new pieces of equipment seem to have a lot of flutter in them that I've had to dead zone out, but it almost seems as if the sim isn't recognizing the dead zones. Has anyone else experienced this and if so, how did you solve it?The other issue I have is related to my lateral and roll trims (rudder and aileron), which may actually have some bearing on the previous issue. I have rudder, aileron, and elevator trim all set to axis on the two extra hat switches on the controller, which I imagined would allow me to easily trim any of the three axis, but only the elevator trim will repeat, even though all three sets of commands are mapped properly and set to a high repeat rate. Is this something to do with my controller, or some shortcoming in FS9? As it is right now, I find it very difficult to trim out the aforementioned rolling / yawing tendencies because I only get one incremental movement for each activation of the command, something that keeps me behind the plane when I am trimming. Also, is there a way to fix this so that the roll / yaw trims will repeat in the same way the elevator will?Thanks and sorry for rambling,Greg

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You may be right about your yoke/pedal combination being a problem. I assume you have calibrated them. Given that the controls are NOT an issue, such rolling/yawing tendencies can also be linked directly to the FDE; in particular wrong values for the moments of inertia. I've found only a few freeware and payware planes get these critical parameters correct. The most common symptom is Dutch Rolls.I don't have my tables with me at the moment, but doing a search in the Aircraft design forum with MOI and either Ron Freimuth or Tom Goodrick will probably come up with a tables of values used to calculate these correctly. Not a hard calculation. I could do it for you if you send me a PM with the planes you are having trouble with. Mike

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Well, unfortunately, there doesn't seem to be any way to actually "calibrate" the X52 and pedals, they are supposedly able to constantly calibrate themselves, but there is no real proof of this ability. As for the source of the problem, I'm thinking more and more that it is a controller problem, as I've noticed it now in all of my aircraft, large and small, and my heli's also. I've tried to dead-zone out the noise that may be there, but even with dead-zones of 50% of the travel, the rolling and yawing are still present. It may be possible that the FDE's are incorrect, but the chances of getting a roll of the same magnitude and with the same characteristics across so many aircraft are really pretty low.On this front, is there a way to force a calibration into the X52 controller? Also, if anyone has experienced such consistence with incorrect FDE's, however unlikely, is there an easy way to correct them all? And finally, I'm still not able to get my rudder and aileron trim buttons to repeat, has anyone had this problem and, if so, how did you get rid of it?

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I don't have the X52 but I do have the pedals and the TQ. I use FSUIPC and am able to calibrate everything as well as assign all functions with it. I delete all assignments in the FS9 assignments windows.You need to purchase the full version of FSUIPC. I wouldn't do without it.Jim D.

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