Flaperons - Stick pressure to LEFT

[jrock836]

I recently purchased my RV12 and I'm working through a few issues that I want to fix.

The #1 issue that I want to work on is the stick pressure to the left I get when flaperons are lowered. The airplane flies hands off during normal cruise, but when flaperons are lowered I get significant stick pressure to the left.

Please give me some ideas of what I can check or do to hopefully get this issue resolved. I don't want to ruin the perfect trim at cruise speed by trying to fix this issue.

Joe - RV12 #120566 ELSA
N49DD

[RFSchaller]

When I retract flaps mine tries to roll right, but flies straight hands off.

[Piper J3]

Hands-off in cruise... Is ball centered?

[mike newall]

You will have to re rig the linkages through the flaperon bellcrank. You are getting more flap on one side as you deploy by the sounds.

[jrock836]

Originally Posted by Piper J3

Hands-off in cruise... Is ball centered?

Yes it is...

[jrock836]

Originally Posted by mike newall

You will have to re rig the linkages through the flaperon bellcrank. You are getting more flap on one side as you deploy by the sounds.

Thanks, I will trying measuring the amount of movement on each side when the are lowered to the 1st and 2nd stop and see how much it differs, if any..

[Tacco]

Lets be clear what you mean by "stick pressure". Do you mean you have to apply stick pressure to keep the aircraft level after the flaps are extended?

It may not be related, but you should be aware that due to the geometry of the control system, if you hold the stick perfectly rigid during flap extension the aircraft will roll right slightly. This is because the stick to bell crank push rod moves in an arc. I compensate, almost sub-consciously, by not holding onto the stick so tightly.

To convince yourself of this, on the ground, hold the stick rigid and not the movement of the opposite stick. It will move out, then in as the flaps are extended.

My two cents anyway.

[jrock836]

Originally Posted by Tacco

Lets be clear what you mean by "stick pressure". Do you mean you have to apply stick pressure to keep the aircraft level after the flaps are extended?

It may not be related, but you should be aware that due to the geometry of the control system, if you hold the stick perfectly rigid during flap extension the aircraft will roll right slightly. This is because the stick to bell crank push rod moves in an arc. I compensate, almost sub-consciously, by not holding onto the stick so tightly.

To convince yourself of this, on the ground, hold the stick rigid and not the movement of the opposite stick. It will move out, then in as the flaps are extended.

My two cents anyway.

As I lower the flaperons the stick starts wanting to move left. I have to apply pressure to keep the stick centered. If I were to let go of the stick, I feel certain the plane would want to roll left. I hope that makes sense..

EDIT: I suppose I could be having a brain fart.. I'll fly it later this week and confirm it's wanting to go left and not right..

[Piper J3]

For data point… my RV-12 flies wings level and ball-centered in cruise flight. Half and full flaps produce no adverse roll. Trimmed for 55 KIAS power-off glide is hands-off wings level.

[Tacco]

Originally Posted by jrock836

As I lower the flaperons the stick starts wanting to move left. I have to apply pressure to keep the stick centered. If I were to let go of the stick, I feel certain the plane would want to roll left. I hope that makes sense..

EDIT: I suppose I could be having a brain fart.. I'll fly it later this week and confirm it's wanting to go left and not right..

When you try it, Hold the stick lightly with two fingers and deploy the flaps. My guess is that the aircraft won’t roll.