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Aileron control problem

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aerosiam

Joined: 26 May 2008
Posts: 59

Posted: Wed Jun 30, 2010 2:08 am Post subject: Aileron control problem

I have had a problem with the feel and response of the ailerons since new.



There feels like a stiffness or binding around the center point for about an inch then the stick moves freely and the ailerons get progressively lighter the more the stick is deflected. Also, in flight there is sometimes a small left or right 'kick' thru the stick also about an inch movement. I have only flown 1 Allegro and I don't know what 'normal' feels like.



Could pilots assist by commenting on their Allegros

1. Is there any stiffness around the center point?

2. Does the stick get lighter the more you move it?

3. Do you ever feel a slight 'kick' thru the stick from the ailerons?



The red bellcrank shaft in the cockpit was misalighned in the factory by about an inch. They had simply pulled it and forced it thru the front bushing.  I realigned it and replaced the nylon bushings with teflon.



In flight, the ailerons used to deflect up until they were flush with the reflexed flaperons (about 4 degrees) I removed the long wing pushrods and replaced them with stiffer steel rods. The original aluminum rods showed signs of wear at 1 point (where 1 of the 3 nylon bearing wheels made contact) It cured the ailerons deflecting at cruise speed and initially seemed to improve the aileron feel. (See an earlier post and photo Feb 2008) but then the original problem remained.



There doesn't appear to be any binding in the wing bellcranks, rod ends or anything else. On the ground, the system seems perfect and has only 200 hours.



The plane is unpleasant to fly especially in turbulence. Around the center, the stick has a similar feel to a throttle friction set a little too tight. The stick moves and responds but every movement takes a slight push after which it travels free.



Rolling 30 left, thru 30 righ however, the stick feels fine and doesn't have any drag when passing thru the center.



An pilot/engineer friend of mine has gone thru the system and flown the plane. he said the control response felt abnormal. He disassembled the cockpit bellcrank then clamped the wing rod ends  looking for play, wear or binding in every part. Nothing.



An airline pilot who started flying ultralights flew it and commented there was nothing smooth and progressive about the roll response from straight and level flight.



Can other owners assist and say if they have experienced any of the above or whether the Allegro has a normal feel or a light feel or whatever.



Paul

brad(at)vision-technology
Guest

Posted: Wed Jun 30, 2010 3:14 am Post subject: Aileron control problem

That certainly doesn't sound normal. By comparison, on long flights I usually just rest my hand at the base of the stick and give it a gentle nudge as needed to keep straight & level. I haven't noticed any significant breakout force and the control response seems normal (except for that sensitive rudder, but that's another story).



It sounds like you've already covered all the usual suspects. The fact that it only happens in the air should be an important clue. Is there excess play in any of the aileron hinges? Maybe one of the ailerons is twisting or moving rearward in flight and causing some binding that you don't experience on the ground. Does the breakout force vary with airspeed? Does flap deflection make a difference?



I'm also curious about the need for stiffer pushrods. I know with the ones on my plane (2003 Allegro 2000) the ailerons don't deflect up in flight. Maybe whatever was causing the deflection is still an issue, but the steel rods fixed one of the symptoms.



It almost sounds like the ailerons are rigged too low. You are 4 degrees below the flaps, but are you sure the flaps are correct? Or maybe the wings themselves are misrigged and causing an aerodynamic difference (and therefore binding) between the two ailerons.



If there is a big difference in the angle between the two flaps or a lot of rudder trim set on the tab, those can be indications that your ailerons or wings are not rigged correctly.

It should be a very nice handling plane, so I certainly hope you get it fixed.



Best of Luck.



Brad Kramer

N221FA - Bismarck ND USA








I have had a problem with the feel and response of the ailerons since new

aerosiam

Joined: 26 May 2008
Posts: 59

Posted: Wed Jun 30, 2010 10:44 am Post subject: Re: Aileron control problem

Brad

Thanks for your detailed reply.



The hinges on the right wing have almost no wear. In contrast, there is slight wear on all the left hinges especially the outer one. The vertical wear seems minor but when the system is clamped and the trailing edge pushed up, it will deflect about 2 degrees.



The breakout force seems to get worse with duration of flight rather than airspeed. Another weird factor in the equation.



Flap setting does not make a difference.



I think you are right that removing the wings and replacing the rods cured a symptom by coincidence rather than dealt with the problem.



I will check your suggestions. The flaps appear reflexed at 4.5 degrees and the ailerons are flush with the tips. I will look at the relative flap angles and rudder trim.



The left aileron trim tab is bent up slightly, the right is level. The plane rolls more easily to the right (presumably it should be the other way round due to torque)



Regards



Paul

brad(at)vision-technology
Guest

Posted: Wed Jun 30, 2010 11:59 am Post subject: Aileron control problem

Wow.  Related to duration of flight???  Could that mean it is temperature related... either something getting warm in the cockpit or cold in the wing?  I can only think of 2 things that change during flight... temperature and weight (& CG). 

  

 Sounds like the aileron/flap rigging is OK. 

  

 I don't recall if I have a tab on each aileron.  I probably do, even though I'm not sure why that would be. Might be worth setting them to neutral so they aren't working against each other and causing some weird problem. It seems to me that having a tab on each aileron could cause ailerons to droop or recess in flight and may even increase the breakout force since there's more inertia to overcome when you first move the stick.  (That's my theory, and I'll stick to it for at least another 10 minutes.  I shouldn' t even speculate on such things when we have mechanical engineers like Thom Riddle on the list).

  

 The only other thing I can think of is the freedom of movement of the torque tube that the control stick attaches to. For instance if something twists just a little bit in flight compared to being on the ground. Or something like the brake cable is restricting movement.

  

 Sounds frustrating.  Should be a big sense of accomplishment when you finally figure it out (and discover it is a simple 5 minute fix).

  

 good luck.

  

 Brad N221FA

  

  

  

 [quote]--

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Thu Jul 01, 2010 2:39 am Post subject: Re: Aileron control problem

Brad,



You seem to have covered the possibilities that have come to my mind, so I can't add anything to that but will be interested to hear what the final solution turns out to be. If I remember correctly, an aileron trim tab on both ailerons was standard practice for Fantasy Air. Only airplane I've seen that did that. I can see no advantage in having two unless the airplane is so out of rig that two are necessary to take out roll bias. If that is the case, two aileron trim tabs is a poor band-aid solution to a bigger problem.



I hope other Allegro owners will respond to Paul's request. I too have flown only one Allegro, yours, and don't have any other to compare it to. But I am certain that Paul's is not normal. I had no trouble with smooth aileron action for the several hundred hours we flew N221FA before we sold it to you, replacing only one aileron hinge during that time. The right side outboard hinge was the one that wore out.

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

aerosiam

Joined: 26 May 2008
Posts: 59

Posted: Thu Jul 01, 2010 10:30 am Post subject: Re: Aileron control problem

Brad and Thom

Thanks for your helpful replies.

I checked items you suggested. 



The rudder trim is neutral. 

With the stick clamped, there is play such that both ailerons can move up about 2 degrees. (Rattle might be a better word) Most of this appears to be in both outer aileron hinges which I will replace (as Thom did). There is more wear in the right aileron hinges than I thought.



The ambient temperature is about 90 and sunny. One possibility is that the bellcrank shaft expands and binds in the bushings on a longer flight. Fitting reflective tape might help but I can't correlate a pattern in terms of hot/cool or high/low when the problem happens.



I will replace hinges, test fly then equalise the trim tabs.



The only other thing I can think of doing is to loosen the wing and strut attachments and reset them (just because removing the wings was part of the process of changing the pushrods after which the system was perfect for a brief period)



Ironically I had the same problem with the rudders being stiff from the factory. The rivetted collar was jamming against the spacer above and just needed machining down.



Paul

aerosiam

Joined: 26 May 2008
Posts: 59

Posted: Wed Jul 07, 2010 6:38 pm Post subject: Re: Aileron control problem

Hi Brad

I had some very helpful emails from Thom. He mentioned that you had a hinge set from Fantasy which included the rivets. Would you mind measuring the rivets? 



 I removed the left aileron and some of the bodies are worn to the point where a 3.2mm pin fits easily in place of the original 3.0mm pin and I may end up having to remove the hinges and drill them all to 3.28mm which is the next available pin diameter.



Thanks



Paul

hgmckay

Joined: 23 May 2006
Posts: 397

Posted: Thu Jul 08, 2010 4:39 am Post subject: Aileron control problem

Paul,



How many hours do you have on your Allegro? Why are you having to remove 

your ailerons?



Hugh McKay

Allegro 2000

Rotax 912UL



--------------------------------------------------

From: "aerosiam" <pk(at)aero-siam.com>

Sent: Wednesday, July 07, 2010 10:38 PM

To: <allegro-list(at)matronics.com>

Subject: Re: Aileron control problem



 	  Quote: 	
		   



 Hi Brad

 I had some very helpful emails from Thom. He mentioned that you had a 

 hinge set from Fantasy which included the rivets. Would you mind measuring 

 the rivets?



 I removed the left aileron and some of the bodies are worn to the point 

 where a 3.2mm pin fits easily in place of the original 3.0mm pin and I may 

 end up having to remove the hinges and drill them all to 3.28mm which is 

 the next available pin diameter.



 Thanks



 Paul





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=304125#304125

aerosiam

Joined: 26 May 2008
Posts: 59

Posted: Thu Jul 08, 2010 7:22 pm Post subject: Re: Aileron control problem

Hi Hugh



200 hours. I have to replace the hinge pins so it's easier just to disconnect the control rod and put the aileron on the bench. With Fantasy out of business, I don't have the option to buy new hinge sets.



Regards



Paul

hgmckay

Joined: 23 May 2006
Posts: 397

Posted: Fri Jul 09, 2010 4:32 am Post subject: Aileron control problem

Paul,



What caused the hinge pins to wear out after only 200 hours! 200 hours is 

nothing for this airplane, and aileron hinges and pins should last far 

beyond 200 hours. I have 400 hours on my Allegro 2000 and the pins and 

hinges show no effect.



Hugh



--------------------------------------------------

From: "aerosiam" <pk(at)aero-siam.com>

Sent: Thursday, July 08, 2010 11:22 PM

To: <allegro-list(at)matronics.com>

Subject: Re: Aileron control problem



 	  Quote: 	
		   



 Hi Hugh



 200 hours. I have to replace the hinge pins so it's easier just to 

 disconnect the control rod and put the aileron on the bench. With Fantasy 

 out of business, I don't have the option to buy new hinge sets.



 Regards



 Paul





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=304283#304283

aerosiam

Joined: 26 May 2008
Posts: 59

Posted: Fri Jul 09, 2010 8:55 am Post subject: Re: Aileron control problem

Hugh



I know, it doesn't make sense. 



The system is perfectly light and free on the ground. Something happens in the air. Going back to my original problem, the stiffness around the center point may be accelerating the wear in the hinges but this seems unlikely.



A pilot/engineer friend of mine agreed the aileron response is odd and disconcerting. He helped dismantle and inspect the system from the wing bellcranks to the control column and he is equally baffled.



The vertical wear in the hinges seemed minor but when the stick was clamped, it translated to about 2 degrees at the trailing edge.



I can't explain the plane's strange handling but getting rid of the wear in the hinges will at least take one factor out of the equation



Paul

brad(at)vision-technology
Guest

Posted: Fri Jul 09, 2010 11:21 am Post subject: Aileron control problem

Strange.. But the rivets I have seem to be about 3.6mm (using my cheap

caliper, so that's approximate).



I do have a new hinge here and the holes in that are noticably smaller

(possibly the 3.2 that you're seeing).  Apparently when Thom replaced my

hinges he drilled out for a larger rivet, just as you're thinking of doing.



Good luck.



--

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Fri Jul 09, 2010 12:22 pm Post subject: Re: Aileron control problem

Brad,



My memory is telling me that the hinge and rivet package that I received from Fantasy Air had two sizes of holes and rivets. Again from memory, I think that the larger holes were on the wing side of the hinge and smaller ones on the aileron side but am not absolutely certain. I did not drill out the holes for larger rivets. Next time you are at the hangar, Brad, get up on a ladder and look carefully at the right outboard aileron hinge (the one I replaced) and compare it and its rivets to the other ones, which I did not replace (came from factory that way).

_________________
Thom Riddle
Buffalo, NY (9G0)

Don't worry about old age... it doesn't last very long.
- Anonymous

aerosiam

Joined: 26 May 2008
Posts: 59

Posted: Fri Jul 09, 2010 8:19 pm Post subject: Re: Aileron control problem

Hi Brad and Thom



Thanks



I think we have a slight miscommunication. The original hinge pin (not rivet size)  is 3.0mm and I am trying out a 3.2mm pin which fits in some of the hinges.



I haven't removed any hinges yet. I am trying to find out what size the rivets are because ordering parts to Thailand is either expensive or long and I try to plan ahead ! Shipping alone is 40 bucks for Fedex.



Regards



Paul

brad(at)vision-technology
Guest

Posted: Sun Jul 11, 2010 3:43 am Post subject: Aileron control problem

Hi Paul,

  

 My hinges also use a 3.0 mm hinge pin.

  

 ...Brad.

  

  

 [quote]--

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