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Interpreting Aileron Position

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dreel(at)cox.net
Guest

Posted: Tue Apr 25, 2006 6:51 am Post subject: Interpreting Aileron Position

I have a feeling my ailerons are trying to tell me something significant about my heavy left wing condition but I'm having trouble getting it.  So, here goes.  In level flight, I'm applying full right manual aileron trim to stay level with the left tank empty.  On the ground, I've established a visual picture of the neutral trail position of the ailerons relative to the wingtips by measurement with a digital level.  So, when I look in the air, I expect to see the left aileron displaced down from neutral and the right aileron displaced up.  What I actually see is the reverse situation.  The left aileron is displaced up and the right down.  What does this mean?



I've checked wing incidence, trimmed up the yaw, set the flaps to neutral trail, and found no vertical displacement errors in the ailerons themselves where they attach to the wing spar using the wing template.  So, according to Van's instructions posted on their web site, I'm at the trailing edge squeezing stage.  Could there be some other factor that would account for the unexpectedly reversed in-flight position?  Something that should be corrected before squeezing?  Or should I just follow Van's advice and squeeze til it flys level?



Dave Reel - RV8A

dbris200(at)sbcglobal.net
Guest

Posted: Tue Apr 25, 2006 7:59 am Post subject: Interpreting Aileron Position

Don't do anything until you try it without the manual trim connected 

(assuming the spring system). The trim system can mask the symptoms and 

could actually be causing the problem.



Dave -6 SoCal

EAA Technical Counselor



DAVID REEL wrote:



 	  Quote: 	
		  



I have a feeling my ailerons are trying to tell me something significant about my heavy left wing condition but I'm having trouble getting it.  So, here goes.  In level flight, I'm applying full right manual aileron trim to stay level with the left tank empty.  On the ground, I've established a visual picture of the neutral trail position of the ailerons relative to the wingtips by measurement with a digital level.  So, when I look in the air, I expect to see the left aileron displaced down from neutral and the right aileron displaced up.  What I actually see is the reverse situation.  The left aileron is displaced up and the right down.  What does this mean?



I've checked wing incidence, trimmed up the yaw, set the flaps to neutral trail, and found no vertical displacement errors in the ailerons themselves where they attach to the wing spar using the wing template.  So, according to Van's instructions posted on their web site, I'm at the trailing edge squeezing stage.  Could there be some other factor that would account for the unexpectedly reversed in-flight position?  Something that should be corrected before squeezing?  Or should I just follow Van's advice and squeeze til it flys level?



Dave Reel - RV8A

stein(at)steinair.com
Guest

Posted: Tue Apr 25, 2006 8:53 am Post subject: Interpreting Aileron Position

Is the ball centered or are you flying with the ball off center somewhat?

This is the 1st thing to look at with heavy wings. If you are skidding

through the air somewhat, that can cause a surprisingly heavy wing.  This

can and is caused by either the Vertical Stab needing adjustment, or more

commonly the gear legs fairings being mis-aligned.  If that isn't the cause,

then you need to get to "squeezing" the light wing down and start fixin.  If

that doesn't work, then the only solution left is to remount the ailierons

with a new  hinge and place them up or down as needed.



Cheers,

Stein.



[quote]--

dennis.glaeser(at)eds.com
Guest

Posted: Tue Apr 25, 2006 9:11 am Post subject: Interpreting Aileron Position

If the left tank is empty, then to compensate, the left aileron would be

UP to compensate.  In essence, the left wing needs less lift - up

aileron - (less weight) and the right wing more lift - down aileron -

(more weight with the fuller tank). So what you are seeing is what I

would expect.



I'm not clear about what you mean by 'full right aileron trim' - which

way are you moving the trim lever?



I agree with Dave Bristol - disconnect the manual trim and fly before

doing anything.



Dennis Glaeser

RV7A




I have a feeling my ailerons are trying to tell me something significant

about my heavy left wing condition but I'm having trouble getting it.

So, here goes. In level flight, I'm applying full right manual aileron

trim to stay level with the left tank empty. On the ground, I've

established a visual picture of the neutral trail position of the

ailerons relative to the wingtips by measurement with a digital level.

So, when I look in the air, I expect to see the left aileron displaced

down from neutral and the right aileron displaced up. What I actually

see is the reverse situation. The left aileron is displaced up and the

right down. What does this mean? I've checked wing incidence, trimmed up

the yaw, set the flaps to neutral trail, and found no vertical

displacement errors in the ailerons themselves where they attach to the

wing spar using the wing template. So, according to Van's instructions

posted on their web site, I'm at the trailing edge squeezing stage.

Could there be some other factor that would account for the unexpectedly

reversed in-flight position? Something that should be corrected before

squeezing? Or should I just follow Van's advice and squeeze til it flys

level? 

Dave Reel - RV8A

khorton01(at)rogers.com
Guest

Posted: Tue Apr 25, 2006 9:45 am Post subject: Interpreting Aileron Position

On 25 Apr 2006, at 10:51, DAVID REEL wrote:



 	  Quote: 	
		   



 I have a feeling my ailerons are trying to tell me something  

 significant about my heavy left wing condition but I'm having  

 trouble getting it.  So, here goes.  In level flight, I'm applying  

 full right manual aileron trim to stay level with the left tank  

 empty.  On the ground, I've established a visual picture of the  

 neutral trail position of the ailerons relative to the wingtips by  

 measurement with a digital level.  So, when I look in the air, I  

 expect to see the left aileron displaced down from neutral and the  

 right aileron displaced up.  What I actually see is the reverse  

 situation.  The left aileron is displaced up and the right down.   

 What does this mean?



 I've checked wing incidence, trimmed up the yaw, set the flaps to  

 neutral trail, and found no vertical displacement errors in the  

 ailerons themselves where they attach to the wing spar using the  

 wing template.  So, according to Van's instructions posted on their  

 web site, I'm at the trailing edge squeezing stage.  Could there be  

 some other factor that would account for the unexpectedly reversed  

 in-flight position?  Something that should be corrected before  

 squeezing?  Or should I just follow Van's advice and squeeze til it  

 flys level?


	


1. Disconnect the trim springs and try it.



2. Remove the gear leg fairings and fly it, to confirm they are not  

causing the problem.



3. Level the aircraft side-to-side on the ground, and be sure your  

ball is centered.  If not, slot the holes on the TC (or EFIS, or  

where ever the ball is), and rotate it to center the ball.  Then, in  

flight, use rudder as required to center the ball.  Add a rudder trim  

tab if required.



4. Carefully inspect the aileron trailing edges.  Are the trailing  

edge radii and contours the same on each side?



5. How is the upper wing skin contour ahead of the ailerons?  If you  

lay a straight edge on the wing skin, is there a difference in  

contour from one side to the other?  If so, this could affect the air  

pressure on top of the aileron, and cause an aileron deflection.



Keep us posted.



Kevin Horton         RV-8 (finishing kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

phil(at)petrasoft.net
Guest

Posted: Tue Apr 25, 2006 9:50 am Post subject: Interpreting Aileron Position

My heavy left wing seems to be caused by a little twist in the flap, so 

you might want to check that  I also don't have much faith in either 

digital levels or the wing template.  Make sure the tooling holes in the 

wing ribs and aileron ribs are lined up.  That's the way we do it on the 

-7's and since the wing is the same it should work on your -8 too. 



And just in case nobody mentioned this... try it without the trim hooked 

up. 



If I had to guess I think the aileron is trying to tell you that your 

airplane is straight and the aileron trim is off.



Godspeed,



Phil Birkelbach - Houston Texas

RV-7 N727WB

http://www.myrv7.com



DAVID REEL wrote:



 	  Quote: 	
		  



I have a feeling my ailerons are trying to tell me something significant about my heavy left wing condition but I'm having trouble getting it.  So, here goes.  In level flight, I'm applying full right manual aileron trim to stay level with the left tank empty.  On the ground, I've established a visual picture of the neutral trail position of the ailerons relative to the wingtips by measurement with a digital level.  So, when I look in the air, I expect to see the left aileron displaced down from neutral and the right aileron displaced up.  What I actually see is the reverse situation.  The left aileron is displaced up and the right down.  What does this mean?



I've checked wing incidence, trimmed up the yaw, set the flaps to neutral trail, and found no vertical displacement errors in the ailerons themselves where they attach to the wing spar using the wing template.  So, according to Van's instructions posted on their web site, I'm at the trailing edge squeezing stage.  Could there be some other factor that would account for the unexpectedly reversed in-flight position?  Something that should be corrected before squeezing?  Or should I just follow Van's advice and squeeze til it flys level?



Dave Reel - RV8A

martin(at)gbonline.com
Guest

Posted: Tue Apr 25, 2006 7:00 pm Post subject: Interpreting Aileron Position

Dave,

Six years ago when I first flew my RV8 I experienced a similar problem. 

After trying every remedy under the sun, I finally noticed that the outer 

aeleron hinge positioned the aeleron about 1/8 inch lower than the inboard 

hinge next to the flap. I had tried all of the other remedies to no avail. 

After many discussions with everybody who had an opinion, it was decided 

that I was experiencing "flow separation" on that aeleron.  I got a new 

hinge from Vans and very carefully fitted it so that the top aeleron surface 

was perfectly even with the wing trailing edge.  this

 corrected the problem and I have flown hands off ever since.  I now have 

1300 hours and still enjoy every minute.

Good luck,

Dick Martin

RV8 N233M

the fast one

---

dreel(at)cox.net
Guest

Posted: Wed Apr 26, 2006 2:34 pm Post subject: Interpreting Aileron Position

After digesting all the replies, for which I thank you all, I got this =

idea from Phil Birkelbachs.  I have adjusted the ailerons so that they =

are both at the same angle of attack on the assumption that they would =

be equally balanced in flight.  Right now, when one is lined up with =

it's flap, the other lines up with the other flap.  Seeing that they are =

indicating a roll to the left by their in-flight position even though =

I'm applying considerable roll right stick input to stay level tells me =

they're not balanced in this position.  What I should be doing is =

decreasing the angle of attack on the powerful aileron, the left one, =

and increasing the angle of attack of the right one to get an in-flight =

balance position with the ailerons closer to the known neutral in-trail =

position.  This will look funny on the ground because they won't line up =

with the flaps but something I can't see or measure is changing the =

airflow each sees & I should adjust to that.



Is this reasonable?  I think I'll just adjust one aileron or the other a =

little 'out of line' to see how this works.



Dave Reel - RV8A

khorton01(at)rogers.com
Guest

Posted: Thu Apr 27, 2006 8:43 am Post subject: Interpreting Aileron Position

On 26 Apr 2006, at 18:33, DAVID REEL wrote:



 	  Quote: 	
		   



 After digesting all the replies, for which I thank you all, I got  

 this =

 idea from Phil Birkelbachs.  I have adjusted the ailerons so that  

 they =

 are both at the same angle of attack on the assumption that they  

 would =

 be equally balanced in flight.  Right now, when one is lined up with =

 it's flap, the other lines up with the other flap.  Seeing that  

 they are =

 indicating a roll to the left by their in-flight position even  

 though =

 I'm applying considerable roll right stick input to stay level  

 tells me =

 they're not balanced in this position.  What I should be doing is =

 decreasing the angle of attack on the powerful aileron, the left  

 one, =

 and increasing the angle of attack of the right one to get an in- 

 flight =

 balance position with the ailerons closer to the known neutral in- 

 trail =

 position.  This will look funny on the ground because they won't  

 line up =

 with the flaps but something I can't see or measure is changing the =

 airflow each sees & I should adjust to that.



 Is this reasonable?  I think I'll just adjust one aileron or the  

 other a =

 little 'out of line' to see how this works.


	


If you are talking about adjusting the length of the various aileron  

pushrods, as a way to fix your roll trim problem, I believe you are  

wasting your time.  If you have the aileron trim in neutral, and you  

let go of the stick, the ailerons will move to the position that  

balances the forces on the left and right ailerons.  If you screw  

around with the pushrods, you might move both ailerons up a bit, or  

down a bit, but I don't believe you will make any significant  

difference the relative positions between the two ailerona.



Go ahead, try it if you want.  But don't be surprised if it doesn't  

fix your problem.



The aileron positions are a symptom of the real problem.  They are  

not the problem.  You need to find the underlying problem, rather  

than trying to treat the symptoms.



Kevin Horton         RV-8 (finishing kit)

Ottawa, Canada

http://www.kilohotel.com/rv8

bertrv6(at)highstream.net
Guest

Posted: Sun May 07, 2006 3:19 pm Post subject: Interpreting Aileron Position

Quoting Kevin Horton <khorton01(at)rogers.com>:



 	  Quote: 	
		   



 On 26 Apr 2006, at 18:33, DAVID REEL wrote:



 > 

 >

 > After digesting all the replies, for which I thank you all, I got

 > this =

 > idea from Phil Birkelbachs.  I have adjusted the ailerons so that

 > they =

 > are both at the same angle of attack on the assumption that they

 > would =

 > be equally balanced in flight.  Right now, when one is lined up with =

 > it's flap, the other lines up with the other flap.  Seeing that

 > they are =

 > indicating a roll to the left by their in-flight position even

 > though =

 > I'm applying considerable roll right stick input to stay level

 > tells me =

 > they're not balanced in this position.  What I should be doing is =

 > decreasing the angle of attack on the powerful aileron, the left

 > one, =

 > and increasing the angle of attack of the right one to get an in-

 > flight =

 > balance position with the ailerons closer to the known neutral in-

 > trail =

 > position.  This will look funny on the ground because they won't

 > line up =

 > with the flaps but something I can't see or measure is changing the =

 > airflow each sees & I should adjust to that.

 >

 > Is this reasonable?  I think I'll just adjust one aileron or the

 > other a =

 > little 'out of line' to see how this works.



 If you are talking about adjusting the length of the various aileron

 pushrods, as a way to fix your roll trim problem, I believe you are

 wasting your time.  If you have the aileron trim in neutral, and you

 let go of the stick, the ailerons will move to the position that

 balances the forces on the left and right ailerons.  If you screw

 around with the pushrods, you might move both ailerons up a bit, or

 down a bit, but I don't believe you will make any significant

 difference the relative positions between the two ailerona.



 Go ahead, try it if you want.  But don't be surprised if it doesn't

 fix your problem.



 The aileron positions are a symptom of the real problem.  They are

 not the problem.  You need to find the underlying problem, rather

 than trying to treat the symptoms.



 Kevin Horton         RV-8 (finishing kit)

 Ottawa, Canada

 http://www.kilohotel.com/rv8



   Kevin:

     My suggestion is try to align both ailerons,  I know it was very difficult
	


for me to do, when I was finishing my Rv6a,,,It took a lot of time and trial

and error, but I was able top algin both ailerons, with the flaps..I do not know

if you meant that one both are align but one side, is different that

the other? how can that be, if you built according to plans?



    I did have to add a shimm on  one side,to match with the flaps, although

it was only about 1/8.  I could have left it that way, but you know...is our

rv....



Just my nickel worth



Bert



rv6a



On my test 40 hrs.



Do not archive

 	  Quote:

dreel(at)cox.net
Guest

Posted: Mon May 08, 2006 7:02 am Post subject: Interpreting Aileron Position

I'm getting nearer the solution to trimming up my RV8A's roll tendencies.

After a long conversation with Rick McBride, who has an RV8 hangered near

me, I now believe that changing pushrod lengths in the aileron control

system will not affect roll tendency.  It will just affect how closely to

the neutral trail position the ailerons balance in-flight.  This affects

drag, but since the up (or down) force on both ailerons is the same,

otherwise they wouldn't balance, there cannot be any contribution to roll.



Somehow, in all the discussion of trailing edge squeezing, I forgot that you

can just make a temporary trim tab and try it.  I was delaying making any

change because I thought of it as permanent.  But, I went back to read Vans

instruction book & now am trying various lengths of trim tab.  One useful

observation in the instructions was that unless the trim tab exceeds 6

inches in length, the rest of the airplane is not seriously out of trim.  So

I tried a wedge 3" wide, 1/4" high, and 1.5 inches long.  Voila!  trim was

now within range of the manual trim system to correct.  What a relief & how

much more enjoyable to fly with fingertip control.  The aileron position in

flight still looks backward, as though it's trying to roll the airplane left

when in fact a right roll correction is being input by the trim tab, but I'm

much less worried about serious structural misalignment now so I've

relegated explaning that to the far back burner.



Dave Reel - RV8A

sbuc(at)hiwaay.net
Guest

Posted: Mon May 08, 2006 8:08 am Post subject: Interpreting Aileron Position

Dave, glad to hear you are getting the aileron trim sorted out.



I am curious about something; during our flight back from Sun-N-Fun, I 

talked to a pilot flying near the Florida panhandle who had a new RV-8 

"toy" and in the course of our chat we briefly discussed roll trim. Was 

that you?  



If in our area, don't hesitate to jump to north Alabama sometime and 

share a fly-in breakfast with us.



Best regards,



Sam Buchanan

Tennessee Valley RV Builders Group

http://www.tvrvbg.org



=====================



DAVID REEL wrote:

 	  Quote: 	
		   

 

 I'm getting nearer the solution to trimming up my RV8A's roll tendencies.

 After a long conversation with Rick McBride, who has an RV8 hangered near

 me, I now believe that changing pushrod lengths in the aileron control

 system will not affect roll tendency.  It will just affect how closely to

 the neutral trail position the ailerons balance in-flight.  This affects

 drag, but since the up (or down) force on both ailerons is the same,

 otherwise they wouldn't balance, there cannot be any contribution to roll.

 

 Somehow, in all the discussion of trailing edge squeezing, I forgot that you

 can just make a temporary trim tab and try it.  I was delaying making any

 change because I thought of it as permanent.  But, I went back to read Vans

 instruction book & now am trying various lengths of trim tab.  One useful

 observation in the instructions was that unless the trim tab exceeds 6

 inches in length, the rest of the airplane is not seriously out of trim.  So

 I tried a wedge 3" wide, 1/4" high, and 1.5 inches long.  Voila!  trim was

 now within range of the manual trim system to correct.  What a relief & how

 much more enjoyable to fly with fingertip control.  The aileron position in

 flight still looks backward, as though it's trying to roll the airplane left

 when in fact a right roll correction is being input by the trim tab, but I'm

 much less worried about serious structural misalignment now so I've

 relegated explaning that to the far back burner.

 

 Dave Reel - RV8A

michele.delsol(at)microsi
Guest

Posted: Wed May 10, 2006 6:36 am Post subject: Interpreting Aileron Position

A little late as I am catching up on my mail but have you checked your wings

for twist? If they are twisted ever so slightly in opposite directions, one

wing's twist will accentuate the other wing's twist then that may be the

problem.



Michele

RV8 - Fuselage



--

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