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  #11  
Old 09-05-2015, 07:55 PM
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catmandu catmandu is offline
 
Join Date: Dec 2005
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Quote:
Originally Posted by lr172 View Post
How did you figure that out?
Started going through all the alignment checks posted by Van's and on here. In the course of that, sighting lines down the trailing edge, noticed right flap, when retracted, sat slightly lower at the fuselage intersection than the left flap. Was not much (1/8" or so), but, apparently, enough.
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  #12  
Old 09-05-2015, 10:08 PM
lr172 lr172 is offline
 
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Location: Schaumburg, IL
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When I rigged the plane, I aligned both ailerons to the tooling holes. I then set the flaps even with the ailerons. Interestingly, during cruise, I noticed that the flaps were riding about 1/4" higher than the ailerons on both sides. There is a bit of slop in the upward movement of flaps in the retracted state. Obviously the airflow was pushing them up. I changed the retracted position of the flaps to this setting. I then extended the flaps to their original position at cruise with the flap motor. This pointed my nose down a bit and cost me 3 MPH. Obviously the airflow didn't want them there. This makes me wonder if my alierons are pointed too much downward and they are finding an equilibrium that favors a left turn.

Maybe I should adjust both ailerons up a bit to see what happens. I sure wish that I had a wing template, but don't know how to get one.

EDIT: I should add that during our first flight, we slowly lowered the flaps near the stall speed. There was no turning tendency, so we assumed that they were adjusted symmetrically. Maybe that was flawed logic.

Larry
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  #13  
Old 09-06-2015, 10:17 AM
JimWoo50 JimWoo50 is offline
 
Join Date: Oct 2005
Location: Chicago sw suburbs
Posts: 371
Default Coffee stirrer

I had heavy right wing. I was all set to slot the brackets and/or pinch the aileron trailing edge when I read on here about taping a 2" length of plastic coffee stirrer on the bottom of the light wing. So naturally I thought my wing was so heavy I taped the whole 5.5in length to the bottom of my left aileron. Wrong now I had a heavy left wing. So I cut it back to exactly 2in and plane flies much better. If I keep the right tank 8 gal. fuller than the left tank, that is enough to counter my 210lbs sitting on the pilots side of centerline and the aircraft will fly nice and straight hands off. So I guess I took the lazy way out but I am having way too much fun flying to risk screwing something up and making a big project out of it.
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  #14  
Old 09-06-2015, 10:23 AM
JimWoo50 JimWoo50 is offline
 
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Location: Chicago sw suburbs
Posts: 371
Default Wing template

I have two you can borrow at Bult Field. One of them needs minor repair. But I have to believe and I may be wrong that if you lined up your ailerons accurately with the tooling holes you should be ok and the templates will be unnecessary.
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  #15  
Old 09-06-2015, 10:31 AM
Carlos Carlos is offline
 
Join Date: Oct 2010
Location: El Campo, Texas
Posts: 4
Default Heavy aileron

The most common cure for a heavy wing, is to sharpen the radius [or as you say pinch the trailing edge] of the LIGHT wing. Let's back up and understand why this trailing edge radius makes such a dramatic effect on the aileron....a large radius trailing edge will actually pull that aileron down due to the high speed air flowing under and attached to the aileron, the top of the aileron is in turbulent flow in flight. Another tried and proven method of correcting the problem is to increase the trailing edge using a rubber hammer and piece of wood and gently tapping the heavy wing aileron [tailing edge] to increase the down force trim on that side. I have adjusted roll trim on at least 6 RVs using the method of both decreasing and increasing the trailing edge radius the effect is dramatic so proceed with caution. If your edge has been sharpened excessively during construction, the only alternative is to increase the trailing edge of the HEAVY WING.

Incidentally, it is worth mentioning that the lightest and quickest rolling RV's have a large radius trailing edge aileron [on both sides]. The reason for this is, as the large radius trailing edge on the down moving aileron is exposed to more airflow the trim effect is like power steering, pulling the down moving aileron in the direction intended. Light and quick is nice on a high performance sport plane. CE
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  #16  
Old 09-06-2015, 01:21 PM
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hydroguy2 hydroguy2 is offline
 
Join Date: Sep 2006
Location: Townsend, Montana
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Quote:
Originally Posted by lr172 View Post
When I rigged the plane, I aligned both ailerons to the tooling holes. I then set the flaps even with the ailerons. Interestingly, during cruise, I noticed that the flaps were riding about 1/4" higher than the ailerons on both sides. There is a bit of slop in the upward movement of flaps in the retracted state. Obviously the airflow was pushing them up. I changed the retracted position of the flaps to this setting. I then extended the flaps to their original position at cruise with the flap motor. This pointed my nose down a bit and cost me 3 MPH. Obviously the airflow didn't want them there. This makes me wonder if my alierons are pointed too much downward and they are finding an equilibrium that favors a left turn.

Maybe I should adjust both ailerons up a bit to see what happens. I sure wish that I had a wing template, but don't know how to get one.

EDIT: I should add that during our first flight, we slowly lowered the flaps near the stall speed. There was no turning tendency, so we assumed that they were adjusted symmetrically. Maybe that was flawed logic.

Larry
my thinking is...you need to start over with the alignment procedure that
Vans recommends. your post reads as if you are assuming some things and chasing others with fixes after making more than 1 change at a time.

pull your wing tips.
line up the tooling holes
set your ailerons...both sides while the other side is securely in position
make sure the stick is centered
align your flaps and properly fit them to the fuselage so they don't move, when retracted.
reinstall your wing tips...does everything line up?

go fly
ball centered?
low speed effects?
high speed?
what happens if you just let go of the stick? hard left, soft turn, dive, climb?
where do the ailerons end up if you let go? (mine rolled hard left when released)
did you burn off fuel from right or left tank?

I followed the guidelines and found my hinge was drilled a bit off. The outboard of the aileron stuck above the wing skin about 1/16"this caused my aileron to deflect upward causing the roll. after moving the outboard hinge down ~1/16"". it quit rolling. BUT I also found my plane to be twitchy at speed and unstable during the roll tests. it would increase roll oscillation if deflected and released vs returning to wings level.
I squeezed both ailerons a tiny bit...they were already painted and you couldn't even tell I changed them. Flys great!
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  #17  
Old 09-06-2015, 02:45 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 3,259
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Quote:
Originally Posted by hydroguy2 View Post
my thinking is...you need to start over with the alignment procedure that
Vans recommends. your post reads as if you are assuming some things and chasing others with fixes after making more than 1 change at a time.

pull your wing tips.
line up the tooling holes
set your ailerons...both sides while the other side is securely in position
make sure the stick is centered
align your flaps and properly fit them to the fuselage so they don't move, when retracted.
reinstall your wing tips...does everything line up?

go fly
ball centered?
low speed effects?
high speed?
what happens if you just let go of the stick? hard left, soft turn, dive, climb?
where do the ailerons end up if you let go? (mine rolled hard left when released)
did you burn off fuel from right or left tank?
I did all of this prior to my first flight. When set this way, with centered ball, I have a heavy left wing that takes my burning off about 10+ gallons with 2 people on board.

I am now looking to either see what went wrong or addressing other areas, such as trailing edge.

Larry
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  #18  
Old 09-06-2015, 06:53 PM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 3,259
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Quote:
Originally Posted by Carlos View Post
The most common cure for a heavy wing, is to sharpen the radius [or as you say pinch the trailing edge] of the LIGHT wing. Let's back up and understand why this trailing edge radius makes such a dramatic effect on the aileron....a large radius trailing edge will actually pull that aileron down due to the high speed air flowing under and attached to the aileron, the top of the aileron is in turbulent flow in flight. Another tried and proven method of correcting the problem is to increase the trailing edge using a rubber hammer and piece of wood and gently tapping the heavy wing aileron [tailing edge] to increase the down force trim on that side. I have adjusted roll trim on at least 6 RVs using the method of both decreasing and increasing the trailing edge radius the effect is dramatic so proceed with caution. If your edge has been sharpened excessively during construction, the only alternative is to increase the trailing edge of the HEAVY WING.

Incidentally, it is worth mentioning that the lightest and quickest rolling RV's have a large radius trailing edge aileron [on both sides]. The reason for this is, as the large radius trailing edge on the down moving aileron is exposed to more airflow the trim effect is like power steering, pulling the down moving aileron in the direction intended. Light and quick is nice on a high performance sport plane. CE
Thanks for your input here. Today I pinched the light aileron a bit and half of my left roll tendency is gone (no heavy wing with 2" Trim tab still on). Before I pinch more, I noticed that the the crispness of aileron has changed. It didn't react as fast. I had read that reducing the trailing edge lessens the sensitivity. I think I will starting making the heavy one fatter and take out what I did today. Both of my ailerons are just slightly over bent according to Van's pictures in the Section 5 document. This tells me that fatting the heavy is probably better than squeezing the light one. Would you agree with this approach?

Larry
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  #19  
Old 10-21-2015, 08:11 PM
maus92 maus92 is offline
 
Join Date: Nov 2013
Location: Annapolis MD
Posts: 387
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I have a heavy right wing after adding electric roll trim and a new Garmin roll servo when I replaced the Dynon D100. Prior to this, the plane flew nice and level. Now i have to add almost full left trim to keep the wings level. Where would I start to diagnose the issue? Should I disconnect the roll trim springs to see if the plane flies level again, or could it be an adjustment of the control arms of the autopilot servo? Note that the autopilot servos are powered off, and have not been engaged/tested yet.

Thanks for any suggestion on how to proceed.
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Last edited by maus92 : 10-22-2015 at 08:48 AM.
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