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Control Problem

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vvkidd(at)mindspring.com
Guest

Posted: Thu Oct 16, 2008 4:04 am Post subject: Control Problem

First flight was 10/6/08.

Zenith Zodiac CH601XL N922VK

Charleston, WV, CRW  RW 23, Winds 230(at)3



Turned left X-wind and encountered a â€˜heavyâ€™ left wing.  Required full Right aileron deflection to     roll back to level on downwind. Continued to require Right aileron to remain level.



Rudder and Elevator seem OK.

Encountered same â€˜Heavyâ€™ problem on Left Base.



Rolled out on Final with a smooth approach at about 70.

Touch down was very smooth, a squeaker. 



Have checked all specs: fore and aft measurements on wing, wing attachment, rigging of ailerons, flaps etc.  Haven't found the problem yet.



Suspect the the left wing isn't developing the same lift as the right.  Don't know why yet.



Anyone else experienced this situation or have any ideas?



Victor

psm(at)att.net
Guest

Posted: Thu Oct 16, 2008 4:16 am Post subject: Control Problem

Hi Victor,



Just a couple of dumb questions.



Do you have aileron trim?



Are flaps firmly held in place?  Does flap position impact the heavy left wing?



My only comment is the obvious point that a Zodiac with a pilot and 

no passenger/copilot will be heavy on the left side.  It is not clear 

to me from you comments whether this CG offset to the left relates to 

your problem or not.



Good luck,



Paul

XL getting close

At 05:03 AM 10/16/2008, you wrote:



 	  Quote: 	
		  Suspect the the left wing isn't developing the same lift as the 

right.  Don't know why yet.

jonathan(at)entry.co.za
Guest

Posted: Thu Oct 16, 2008 4:21 am Post subject: Control Problem

Are you sure the Flaps are not asymetrical? Sounds like this could be the

problem, if it is only on downwind base and final? Is the amount of Aileron

deflection correct?



In my XL I have never even experience the left wing heavy syndrome, and looking

at the rim tab, after landing, it is perfectly flat. The only time I need to use

the aileron trim tab is when I use more fuel out of one tank than the other.



That said, I do use rudder AND aileron most of the time, an especialy on final,

when it is very gusty.

 	  Quote: 	
		  

Turned left X-wind and encountered a 'heavy' left wing.  

Required full Right aileron deflection to     roll back to 

level on downwind. Continued to require Right aileron to remain level.

vvkidd(at)mindspring.com
Guest

Posted: Thu Oct 16, 2008 5:18 am Post subject: Control Problem

Aileron deflection is within limits 11.5 +/- 1 deg. both sides.  Can't find any problem with flaps.  

I've only had two flights both in the pattern both with the same heavy wing problem.  I do not have aileron trim.



Thaks, 



Victor



--

vvkidd(at)mindspring.com
Guest

Posted: Thu Oct 16, 2008 5:22 am Post subject: Control Problem

No aileron trim.  Flaps are filmly in palce and do not droop. On the second flight I had a fellow builder on board, had to go to experience for help, he felt that he left wing wasn't developing as much lift as the right.



This is not due to CG.  After the 1st lf turn on climg-out, I have to full right aileron to level the plane.  Some rgt aileron is required on downwind.  Increeased speed seems to add to the problem.  On final at abt 60, the controls seem almost normal.  



Victor



--

K Dilks

Joined: 22 Sep 2008
Posts: 108
Location: UK

Posted: Thu Oct 16, 2008 5:30 am Post subject: Re: Control Problem

Sorry to say this but i am sure you have one wing either at a different angle of attack  in relation to the other or one wing has some wash out / wash in built in to it. IE its twisted.

 Time for a full rigging check...

 Had this on some RPVs I used to fly and on a microlight i bought years ago one wing was twisted giving the same result.

 Cheers 

Kev

_________________
Back home .................

jonathan(at)entry.co.za
Guest

Posted: Thu Oct 16, 2008 5:50 am Post subject: Control Problem

When I rigged my XL, I lay on my back, behind the plane, and 'sighted' the wing

for straitness, we always do this models when building. You can sight the tail

and the wings, and then wings together, move you head until the trailing edges

of both wings line up, I am sure you will see a 'twist' The Twist is also

explained by the plane feeling normal at lower speeds, as the twist will be far

more effective at higher speeds.



Another possibilty is the washout in each aileron, is it the same, if I remember

(two years ago) it is 13mm at each tip.



HTH

Jonathan

150+ hrs and luvin it!

Checked by AVG - http://www.avg.com 

PM

ter_turn(at)yahoo.com
Guest

Posted: Thu Oct 16, 2008 6:28 am Post subject: Control Problem

Victor, this control problem is potentially very serious. I wouldn't fly any more until consulting with ZAC. Maybe a trim tab, stationary or electric is the fix, but please discuss it with Zenith. Let us know the outcome, please!



Terry Turnquist

601-XL Plans

St. Peters MO



vvkidd(at)mindspring.com wrote:[quote] --> Zenith601-List message posted by: vvkidd(at)mindspring.com



No aileron trim.  Flaps are filmly in palce and do not droop. On the second flight I had a fellow builder on board, had to go to experience for help, he felt that he left wing wasn't developing as much lift as the right.



This is not due to CG.  After the 1st lf turn on climg-out, I have to full right aileron to level the plane.  Some rgt aileron is required on downwind.  Increeased speed seems to add to the problem.  On final at abt 60, the controls seem  almost normal.  



Victor



--

pdn8r(at)yahoo.com
Guest

Posted: Thu Oct 16, 2008 7:16 am Post subject: Control Problem

Certainly don't know if this is the problem but on my RV-8 I had a heavy left wing on the initial flights and turned out to be the trailing edge of the ailerons being slightly different (not visible) radius.  Actully fixed the problem by squeezing the opposite of heavy wing (in my case the right) aileron with seam pliers (very lightly) thus decreasing the radius and placing a block of wood along the trailing edge of the heavy wing aileron and tapping (again lightly) with a rubber mallet, thus increasing the radius and it actually fixed the problem to hands off.  None of this "adjustment" made a visible difference but very slight differences can make a big difference in handling characteristics.

  

 Just an idea.



Bill PaganEAA Tech Counselor #4395

--- On Thu, 10/16/08, vvkidd(at)mindspring.com <vvkidd(at)mindspring.com> wrote:



  	  Quote: 	
		  From: vvkidd(at)mindspring.com <vvkidd(at)mindspring.com>

Subject: Control Problem

To: zenith601-list(at)matronics.com

Date: Thursday, October 16, 2008, 8:03 AM



 	  Quote: 	
		  --> Zenith601-List message posted by: vvkidd(at)mindspring.com



First flight was 10/6/08.

Zenith Zodiac CH601XL N922VK

Charleston, WV, CRW  RW 23, Winds 230(at)3



Turned left X-wind and encountered a ¡heavy¢ left wing.  Required full

Right aileron deflection to     roll back to level on downwind. Continued to

require Right aileron to remain level.



Rudder and Elevator seem OK.

Encountered same ¡Heavy¢ problem on Left Base.



Rolled out on Final with a smooth approach at about 70.

Touch down was very smooth, a squeaker. 



Have checked all specs: fore and aft measurements on wing, wing attachment,

rigging of ailerons, flaps etc.  Haven't found the problem yet.



Suspect the the left wing isn't developing the same lift as the right. 

Don't know why yet.



Anyone else experienced this situation or have any ideas?



Victor

	
	


         [quote][b]

ggower_99(at)yahoo.com
Guest

Posted: Thu Oct 16, 2008 8:16 am Post subject: Control Problem

Hello Victor,

  

 I am still building my XL, ready to start the wings, so I cant give first hand advise about it.

 But for what you say, could be twist in either or both wings, while building them.  

 How to check the rigging in your plane?  I dont know in the XL, at this moment, but maybe asking someone in ZAC.

  

 Any instructions/solutions you get, we all will appreciate very much sharing.

  

 Saludos

 Gary Gower

 Flying from Chapala, Mexico.

 701 912S

 Building 601XL  Jab 3300.



--- On Thu, 10/16/08, vvkidd(at)mindspring.com <vvkidd(at)mindspring.com> wrote:



 [quote]From: vvkidd(at)mindspring.com <vvkidd(at)mindspring.com>

Subject: Re: Control Problem

To: zenith601-list(at)matronics.com

Date: Thursday, October 16, 2008, 9:21 AM



[quote]--> Zenith601-List message posted by: vvkidd(at)mindspring.com  No aileron trim.  Flaps are filmly in palce and do not droop. On the second flight I had a fellow builder on board, had to go to experience for help, he felt that he left wing wasn't developing as much lift as the right.  This is not due to CG.  After the 1st lf turn on climg-out, I have to full right aileron to level the plane.  Some rgt aileron is required on downwind.  Increeased speed seems to add to the problem.  On final at abt 60, the controls seem almost normal.    Victor  --

DaveG601XL

Joined: 27 Oct 2006
Posts: 351
Location: Cincinnati, Oh

Posted: Thu Oct 16, 2008 9:22 am Post subject: Re: Control Problem

Victor,



I assume your rudder is in the neutral position with the pedals even?  Did you try using rudder to lift the wing during your flights?  



Good luck resolving this,

_________________
David Gallagher
Cincinnati, OH area

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Thu Oct 16, 2008 9:52 am Post subject: Control Problem

Make sure the rudder is properly centering in level flight. The Zodiac  

has a powerful rudder and the plane will bank in the direction of the  

rudder deflection. You can even bank the airplane with just the rudder  

alone or use it to help level the wings.

 	  Quote: 	
		   



 Turned left X-wind and encountered a ‘heavy’ left wing.  Required  

 full Right aileron deflection to     roll back to level on downwind.  

 Continued to require Right aileron to remain level.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

ideaz1(at)sbcglobal.net
Guest

Posted: Thu Oct 16, 2008 7:01 pm Post subject: Control Problem

I agree on two points. First don't fly again till you find the problem and 

fix it. Second, a likely problem is different washout between the two wings. 

It's really easy to check with a four foot or longer level or other straight 

edge placed on the wing tip area with the plane on a level surface and 

measure to the floor at front and back. The measurements should be really 

close (I'm not sure what the spec is right now)from wing to wing. Sounds 

like the right wing has a greater angle of incidence so more lift. The 

danger is if you bank left too hard you may be unable to recover without 

doing something radical like full roll to the left, which is not a good idea 

in the pattern.

Don't mean to scare you but I have been in this exact situation and I was 

not happy!



Best of luck

Dirk

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