FLUTTER ISSUES

[Vic3D]

Ok guys, I need some help. This is driving me nuts and I have no clue what to do.

My plane (AW 260) has progressively started to flutter the ailerons when I go past 1/3 throttle in a straight line. I have Hitec 5945 servos, 1-1/4'' arms, and the horns are all installed per the manual. Everything from servos, to arms, to horn placement is per the manual. 180 oz is plenty for this application... Using the stock 4-40 rods. It doesn't flutter violently as if the surface was loose, but it does flutter probably half the aileron travel both ways. It bent one of the aileron rods. I replaced all rods with new ones and with a carbon tube over them for stiffer pushrods.

My prop and spinner are balanced, the servos are matched perfectly. What's wrong???

[ShortBus]

maybe the gears are stripped

[warren cross]

Are the ailerons sealed?? Hinges good and tight? Dont take much to make flutter but a whole lot to track it down ad fix it. My 2cts

[tony-amps]

Vic,
Use the h9 titanium rods they will never bend. Also make sure that your linkage is at least 1" above the aileron and like shortbus says check your servos.

Tony

[Vic3D]

Tony, all the gears are fine. It flutters on both ailerons. Hinges are tight and are sealed.

[BDSBob]

What is the distance from the hinge line to the pivot point on the control horn?

[Vic3D]

	Quote: Originally Posted by warren cross
	Are the ailerons sealed?? Hinges good and tight? Dont take much to make flutter but a whole lot to track it down ad fix it. My 2cts

I know! Tell me about it.

[Vic3D]

	Quote: Originally Posted by BDSBob
	What is the distance from the hinge line to the pivot point on the control horn?

1-1/4''

[Dennis C]

Well if your hinges are tight and sealed & servos are tight. then i would think you have a problem in your gemotry set up.

[BDSBob]

You do have a 1-1 mechanical setup. I prefer more mechanical advantage.

The manufacturer's servo torque numbers are made using 1" arms, so you are not utlizing the servo to it's full potential.

Assuming that you have other holes on the servo arms, I would move them down to the 1" mark. This would give you more mechanical advantage against the aileron.

You will obviously need to set up the throws etc. One advantage is that you will now be able to increase the endpoints using the radio, increasing resolution.

[Shawn Berkheimer]

What servo arms are being used and how are the servos powered, are there any Y connectors used? have you load tested the battery?


Shawn

[Vic3D]

BDS and Shawn,

Each servo has its own power supply with the Power Expander (Smart Fly).

[paffy]

Is it possible that your pushrods are flexing ? How log are they and what are they made of ?

[DKjens]

	Quote: Originally Posted by BDSBob
	You do have a 1-1 mechanical setup. I prefer more mechanical advantage. The manufacturer's servo torque numbers are made using 1" arms, so you are not utlizing the servo to it's full potential. Assuming that you have other holes on the servo arms, I would move them down to the 1" mark. This would give you more mechanical advantage against the aileron. You will obviously need to set up the throws etc. One advantage is that you will now be able to increase the endpoints using the radio, increasing resolution.

What are you talking about, if he has a 1:1 mechanical ratio, then the ailerons see exactly the same torque as the servos put out. You could have 2" arms on the servos and 2" from hinge line to pivot point, and the result would be the same. It is actually good to have longer arms as long as the ratio is 1:1, since the force on the connecting rod will be less, and any slop found in the ball links or other will play a lesser roll in the set up.

[ShortBus]

I wouldn't use 4-40 rod on a 35%, but thats just me.