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Nanchang aileron balancing

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yakjock(at)gmail.com
Guest

Posted: Fri Jan 11, 2008 11:12 pm Post subject: Nanchang aileron balancing

We are in the process of remounting the ailerons onto 88 (the project).  We want to make sure we get the balance right as we have installed a trim motor on one side.  Does anyone on the list have information on the factory settings or know where we might get this information?  For those of you who have balanced the ailerons we would appreciate hearing what and how you did it. 

  

 Thanks for the help.

  

 Hal Morley

  [quote][b]

cjpilot710(at)aol.com
Guest

Posted: Sat Jan 12, 2008 7:34 am Post subject: Nanchang aileron balancing

In a message dated 1/12/2008 2:13:24 A.M. Eastern Standard Time,  yakjock(at)gmail.com writes:

  

 Hal,

  

 If I am not mistaken, balancing is balancing so to speak.  For  ailerons and even elevators and rudders, the pivot point is the  hinge.  The aileron should be balanced so that it stays at whatever angle  you put it while its sitting on the pivot points which is the aileron attach  bolts.  That is a fairly standard way of doing it for every airplane I've  recovered.  I am about to recover some ailerons for a TMB and planned to do  the same.

  

 The travel range (up & down) is adjusted, if I remember correctly on  the control tube under the floor. I do believe the angles are listed near the  front of the manual.

  

 Jim "Pappy" Goolsby

  

  	  Quote: 	
		     We are in the process of remounting the ailerons onto 88 (the    project).  We want to make sure we get the balance right as we have    installed a trim motor on one side.  Does anyone on the list have    information on the factory settings or know where we might get this    information?  For those of you who have balanced the ailerons we would    appreciate hearing what and how you did it. 

    

   Thanks for the help.

    

   Hal Morley

	


 

  



Start the year off right.  Easy ways to stay in shape in the new year. 

  [quote][b]

wlannon(at)persona.ca
Guest

Posted: Sat Jan 12, 2008 11:49 am Post subject: Nanchang aileron balancing

Hi Hal;

  

 I have not been able to find the control surface  balance limits for the CJ. Quite likely that information is in the Structural  Repair manual which,as far as I know, has never been translated to  English.

  

 I have balance checked only one set after  recovering and found them within the limits for the Harvard (or T6). Can't  recall the specific numbers right now. 

 These limits MAY NOT be acceptable for the CJ but  may be useful as a guide.

 With subsequent recovering jobs I have not  rechecked balance since there have been no repairs that could effect balance and  my procedure and material usage is identical each time.

  

 There is a process I intended to carry out but  have, so far, failed to do to determine an estimate for the CJ balance limits.  One excuse for this failure is that my gram balance scale disappeared during the  move to the Okanagan 12 years ago.

  

 Using the standard procedure, balance each control  surface as removed from the aircraft and record the unbalance moments. If  there is no sign of structural repair and the fabric is intact and reasonably  clean it should be acceptable to use these numbers as the limit.

 If that is not possible balance an uncovered set  (clean, no repairs) and record the moments. Using a little ingenuity with some  doped fabric one should be able to come up with acceptable limits.

  

 Procedure:  

  

 Fabricate mating hinge fixtures for each control  surface and attach these to a level table surface. Hinge points must be in  alignment and level and at a known height above the surface.

  

 Attach the control surface and measure the  unbalance moment (oz. inches, etc) with a precision balance scale at a  convenient location on the trailing edge. This will likely be a positive number  (T/E heavy) but it is possible that some aircraft may require an overbalance  (T/E light)

  

 Note to Jim;

  

 I'm sure if you were to refer to the appropriate  military aircraft manual for the TBM you will find specific balance limits in  the xxxxxx-3 (Structural Repair)

 RCAF ( or RCN) - Engineering Order,

 USAF - Technical Order (but probably had no  TBM's)

 USN  -  Beats me but you likely  know

  

 Cheers;

 Walt

  

 --

wlannon(at)persona.ca
Guest

Posted: Sat Jan 12, 2008 12:51 pm Post subject: Nanchang aileron balancing

Hal;

  

 My apology! 

 I sent a diatribe on control surface balancing that  may be of use for CJ elevators and rudder and all surfaces on most other  aircraft but has no applicability to the CJ6 aileron.

  

 The reason is that the CJ6 aileron is not an  individually balanced surface. It is part of a balanced  system!  Installed on the aircraft each aileron is effectively  balanced by the opposing aileron through a rigid push-pull rod control  system.  Obviously that would not be possible with a cable  system. 

 While this sounds logical and good it does not  comply with Western aircraft certification standards (at least the old ones I am  familiar with), whether rod or cable operated.  What happens if you forget  one cotter pin and this excellent push-pull system is suddenly  disconnected?

  

 For your situation I would suggest you do not  change the weight or configuration of one aileron over the  other. 

  

 Walt 

   

 [quote]   ---

cjpilot710(at)aol.com
Guest

Posted: Sat Jan 12, 2008 4:35 pm Post subject: Nanchang aileron balancing

In a message dated 1/12/2008 3:52:21 P.M. Eastern Standard Time,  wlannon(at)persona.ca writes:

  

 This might be a good time to start a discussion about WHY flight controls  are balanced.  Those real certified engineers amongst us (I am not  one) could (please in layman's terms) explain why it is done.

  

 My education on the subject is from EAA manuals, shop experience, and  hangar shop talk.  I do not pretend to be an expert cause I don't have the  paper on the wall.  

  

 I was to understand that balancing the control were for 2 basic  reason.  1. For control system function, in that the pilot would not have  to input constant control correction for a system that was out of balance.   2. Help to eliminate the possibility of control flutter (although I understand  that shape had a lot to do with that).

  

 The latter making sense to me when it came to the rudder which is mounted  vertically and would appear to less likely be effected by an out of balance  condition.

  

 In all my readings of aircraft repair, I've never seen where it said that a  certain out of balance condition (trailing edge heavy or light) would be  needed.  But I have not read every manual either.  

  

 BTW I am trying find a TBM manual at this time.  The flight control  fabric is rib stitched, but because of the way the rib are made, you can  not use the standard FAA approved rib stitch.  Grumman had did something  different.

  

 Also the procedure you outline is the one I've used and understood as  a "standard" way of balancing.

  

 Awaiting to be elucidated. 

  

 Jim"Pappy" Goolsby

  

 [quote]   Hal;

    

   My apology! 

   I sent a diatribe on control surface balancing    that may be of use for CJ elevators and rudder and all surfaces on most other    aircraft but has no applicability to the CJ6 aileron.

    

   The reason is that the CJ6 aileron is not an    individually balanced surface. It is part of a balanced    system!  Installed on the aircraft each aileron is effectively    balanced by the opposing aileron through a rigid push-pull rod control    system.  Obviously that would not be possible with a cable    system. 

   While this sounds logical and good it does    not comply with Western aircraft certification standards (at least the old    ones I am familiar with), whether rod or cable operated.  What happens if    you forget one cotter pin and this excellent push-pull system is suddenly    disconnected?

    

   For your situation I would suggest you do not    change the weight or configuration of one aileron over the    other. 

    

   Walt 

     

   [quote]     ---

JOE HOWSE

Joined: 10 Jan 2006
Posts: 140
Location: DUNCAN BC CANADA

Posted: Sat Jan 12, 2008 7:38 pm Post subject: Nanchang aileron balancing

Grumman ribs are similar to the CJ however they used a continuos wire clip  for attachment.

 The Stits manual says to use the original system if possible.

 I have recovered several sets of CJ ailerons and found that some had 

 a counterweight in the leading edge as well as the standard tip CW,

 I assumed  that as long as they were matched, ie. left and  right,

 that either method was acceptable.

 But like Walt points out, not so critical with the push rod system.

  

 Joe

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_________________
J.C. HOWSE

cjpilot710(at)aol.com
Guest

Posted: Sat Jan 12, 2008 9:54 pm Post subject: Nanchang aileron balancing

In a message dated 1/12/2008 10:40:07 P.M. Eastern Standard Time,  joeh(at)shaw.ca writes:

  

 Are you sure about the TBM using a wire clip?  I called a well known  warbird shop out in CA. and they told me it was stitched.

  

 Man!  I just got to find a manual.

  

 Pappy

  

  	  Quote: 	
		     Grumman ribs are similar to the CJ however they used a continuos wire    clip for attachment.

   The Stits manual says to use the original system if possible.

   I have recovered several sets of CJ ailerons and found that some had    

   a counterweight in the leading edge as well as the standard tip CW,

   I assumed  that as long as they were matched, ie. left and    right,

   that either method was acceptable.

   But like Walt points out, not so critical with the push rod system.

    

   Joe



 	  Quote: 	
		   	
	


 

  



Start the year off right.  Easy ways to stay in shape in the new year. 

  [quote][b]

JOE HOWSE

Joined: 10 Jan 2006
Posts: 140
Location: DUNCAN BC CANADA

Posted: Sun Jan 13, 2008 7:05 am Post subject: Nanchang aileron balancing

I have not worked on a  TBm, I was referring to the

 fabric attachment wire clip system on the Mallard.

  

 Joe

    [quote][b]

_________________
J.C. HOWSE

wlannon(at)persona.ca
Guest

Posted: Sun Jan 13, 2008 11:21 am Post subject: Nanchang aileron balancing

Hi Joe;

  

 The CJ6 aileron has no provision for a tip balance weight  installation. The only possible location is within the L/E.

 I recovered a set of controls for the CG5 (Yak 1 a few years back  and, if my memory is correct, those ailerons were balanced. That is quite  possibly true of all the Yak models. For certain if the ailerons are cable  operated.

 The CJ6 is the only aircraft I have ever been involved with that uses  unbalanced ailerons. No need to strip the fabric to determine that. Just pick it  up.

  

 Cheers;

 Walt

 [quote]   ---

wlannon(at)persona.ca
Guest

Posted: Sun Jan 13, 2008 11:21 am Post subject: Nanchang aileron balancing

Jim;

  

 To the best of my knowledge control surfaces are balanced to provide a  damping effect which will eliminate or reduce the destructive effect of control  surface flutter. 

  

 I believe the design operating speeds have a great deal to do with the  criticality of balance. The Harvard allows a surprising amount of under balance  (T/E heavy) for the elevator and rudder (in the area of 2 to 3 lbs.)   

 Ailerons are far more critical. For example the maximum under balance for  the Harvard aileron is 13 oz.  Actually a much larger difference than  indicated since the measuring arm is less than half that of the elevator.

  

 Check out the web for the TBM manuals. A company called ESSCO lists the TBM  Structural Repair for $51.00.

  

 Cheers;

 Walt 

 [quote]   ---

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