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Old 07-15-2017, 01:02 PM   #1
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Default Aileron bell crank angle

I want to check the rigging of my S-2A. I assume that the aileron pushrod idler should be at right angle to the front spar when the aileron is neutral.

But, the bell crank appears to have an acute angle between it's arms, about 80degrees. Which way should it positioned with the stick neutral? I assume one arm or the bell crank should be perpendicular or parallel to the spar?

My S2A has the frieze ailerons if it makes a difference.


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Old 07-15-2017, 01:47 PM   #2
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Anthony,
Yours looks to be per plans.
70 degrees between the two arms.


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Old 07-15-2017, 03:14 PM   #3
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The drawing I have shows a slightly different geometry. Neither arm is aligned but this is not a rigging drawing so take it for what it's worth;

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Old 07-16-2017, 03:18 AM   #4
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Quote:
Originally Posted by Dennis Flamini View Post
Anthony,
Yours looks to be per plans.
70 degrees between the two arms.
Thanks for that. Is that from the S2 drawings? Interesting that they stipulated 14 degrees from perpendicular.
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Old 07-16-2017, 03:03 PM   #5
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Anthony,
i do not have bellcrank drawings. The photo is from S2A lower wing assembly and i just measured the angles from there. i assume the factory showed the bellcrank in the neutral position and were accurate as to bellcrank arms, angles, etc.
Bill's drawing is from the standard ailerons, the one i show is from the symm. ailerons. They both have the slight offset from perpendicular to spar.
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Old 07-17-2017, 03:12 AM   #6
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Okay, thanks for going to that trouble. Unfortunately the factory can be difficult to get info from and in this part of the world there are lots of well meaning "experts" who's advice I follow with trepidation.

It's nice to get advice from someone who has actual drawings. If you ever want to sell your S2 drawings let me know!
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Old 07-17-2017, 12:53 PM   #7
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Default Rigging

IIRC the friese ailerons had a bit of differential in the travel. Herb Anderson told me they used the standard friese aileron bellcranks with the symmetrical ailerons but rigged the neutral position of the bellcranks to make the TRAVEL as equal as possible.
Consider also that the aileron pushrod attachment at the stick/torque tube is different between the S1 and S2 models.
The slave strut arms on the S1T are also not designed for optimal travel.
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Old 07-17-2017, 01:10 PM   #8
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The drawing I posted was from the later wings with symmetrical ailerons. The bellcrank is very different to the one Dennis posted so maybe, at some point, they did change the design to optimize the travels for the newer ailerons.


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