Observations
Hi Guys,
Today I removed the seat floor to see what is going on. As noted elsewhere, the bulkhead is now distorted where the stabilitor cables are tensioned. I suppose I'll have to slacken off the turnbuckles to reinstall the floor. Ugh, I hate that turnbuckle job.
When you install a bolt to lock the controls in the central position I see that the Y-shaped bellcrank is not aligned exactly fore and aft. Looking from the top it is rotated slightly anticlockwise. This should automatically introduce a slight droop in the left flaperon and raise the right one, other things being equal. I couldn't find a step in the plans to introduce the 1/8" down/up, so maybe this is how it happens automagically. Certainly the bias is in the appropriate direction.
The offset also means that if you prepare the two control stick torque tubes with equal lengths, the right stick is not vertical. Seems there should be a step in the plans to check this. I have now adjusted mine by lengthening the right tube.
None of this explains my significantly non-symmetrical flaperons. I have adjusted the lengths of the two long torque tubes. I have still got the required 1/4" variation from left to right as called out in the PAP, but this time with the controls locked in the central position (which was not specified in the PAP, or the plans as far as I can see). I also get maximum up/down deflections on the flaperons within 1 degree of each other in the flaps-raised position. As it happens not much adjustment was required to eliminate the asymmetry I measured. Maybe three turns of the rod-end bearings.
All of this feels better, but in the absence of any max deflection angles from Vans I don't know if it correct or not.
I also haven't removed the tank and the baggage bay inspection covers to look at the rear end of the torque tubes. Is it safe to assume that a slight shortening of one tube will not risk an over-centre situation which might lock the controls?
Thanks for your perseverance. I think I have learned more in the two months of debugging, than in the year of building. It's relatively easy slavishly following the plans with no comprehension of what's really happening.
FWIW, I have remeasured the angles.
With flaps up, I am now seeing a maximum up deflection of 22 degrees (port) and 23 degrees (starboard). Max down deflection is 11 degrees (port) and 12 degrees (starboard).
Full flaps lowers the port flaperon by 20 degrees, and the starboard flaperon by 18 degrees with the sticks centralised.
Full up deflection with full flaps results in 0 degrees (port), 2 degrees down (starboard). Full down deflection is 30 degrees (port) and 28 degrees (starboard).
Cheers...Keith