Aileron travel/range adjustment

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Aileron travel/range adjustment

Post by billswire » Fri Sep 01, 2023 10:49 pm

Hi everyone...

I'm really struggling with adjusting the range/travel of my aircraft's ailerons.

I was wondering if there was a standard process or procedure, perhaps used by pro aerospace engineers, to resolve these types of rigging issues.

Mechanically I think the control system (pushrods and bellcranks) in my aircraft is pretty standard:
  • The system comprises a central cable circuit attached to the yoke (with two turnbuckles in the circuit, port and stbd). From the rear of the cable circuit, pushrods laterally down each wing, each of which terminate at a bellcrank which converts the lateral pushrod movement into longitudinal movement of another pushrod (which connects to a horn on each aileron).
  • A turnbuckle on each side of the central system cable circuit allows the cable to be tensioned and compensatory changes to the turnbuckles allow the 'zero' position to be altered (port or stbd).
  • The lateral (wing) pushrods are each adjustable by 5-6 threads of a single M6 rose joint (at the bellcrank end of each pushrod).
  • The longitudinal pushrods from each wing's bellcrank to that wing's aileron are adjustable by approximately twice that much (a rose joint on each end of the pushrod).
I'm looking for any help or previous experience - surely this is something most of will have tackled when rigging... but my ailerons' range is 45% too much in the UP direction and 30% too much in the down direction and I've had to admit to myself that I simply don't understand how to fix this after months (elapsed) of effort... I've been trying to boil this down to simple changes and their effects, but I've been unable to get anywhere near where I need to be.

I'm losing sleep over this! Any help would be really, *really* appreciated.

Bill Swire

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