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  #1  
Old 02-22-2021, 09:37 PM
jrock836 jrock836 is offline
 
Join Date: Nov 2020
Location: Burleson, Texas
Posts: 31
Default Flaperons - Stick pressure to LEFT

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

Last edited by jrock836 : 02-22-2021 at 09:39 PM.
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  #2  
Old 02-22-2021, 10:31 PM
RFSchaller RFSchaller is offline
 
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Location: Phoenix, AZ
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When I retract flaps mine tries to roll right, but flies straight hands off.
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  #3  
Old 02-22-2021, 11:11 PM
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Piper J3 Piper J3 is offline
 
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Hands-off in cruise... Is ball centered?
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Jim Stricker
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 633

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
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  #4  
Old 02-23-2021, 06:16 AM
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mike newall mike newall is offline
 
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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.
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  #5  
Old 02-23-2021, 07:33 AM
jrock836 jrock836 is offline
 
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Location: Burleson, Texas
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Quote:
Originally Posted by Piper J3 View Post
Hands-off in cruise... Is ball centered?
Yes it is...
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  #6  
Old 02-23-2021, 07:35 AM
jrock836 jrock836 is offline
 
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Location: Burleson, Texas
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Quote:
Originally Posted by mike newall View Post
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..
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  #7  
Old 02-24-2021, 02:54 PM
Tacco Tacco is offline
 
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Location: White Salmon, WA
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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.
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RV-12 N12SM
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  #8  
Old 03-01-2021, 12:36 AM
jrock836 jrock836 is offline
 
Join Date: Nov 2020
Location: Burleson, Texas
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Quote:
Originally Posted by Tacco View Post
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..
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RV-12 ELSA #120566
Hawkins Airstrip ( 35TT )

Last edited by jrock836 : 03-01-2021 at 01:28 AM.
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  #9  
Old 03-01-2021, 02:16 AM
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Piper J3 Piper J3 is offline
 
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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.
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Jim Stricker
EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 633

LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H
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  #10  
Old 03-01-2021, 07:20 PM
Tacco Tacco is offline
 
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Location: White Salmon, WA
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Quote:
Originally Posted by jrock836 View Post
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.
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RV-12 N12SM
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