FritzW
Well-Known Member
We have a transient Waiex passing through our local airport. The pilot (a friend of our own Victor Bravo) is enroute from Oshkosh to the L.A. area. He was having some control issues and stopped here (Las Cruces, NM) to check it out.
He reports:
1) The nose goes right when he takes off.
2) But... he has to hold a bunch of right rudder at cruise. (high power, high speed)
3) The rudder pedals are neutral during a reduced power decent. (lower power, high speed)
4) He has to hold left rudder when the power is off. (low power, low speed)
...before you say "it's a thrust line issue", the thrust line is 'dead nuts' perfect per the plans, and a gazillion Sonex/Waiex's fly fine with the "per the plans" thrust line.
We've found:
1) The thrust line is dead on (per the plans).
2) The tailwheel and stub rudder are way out of alignment. ...~1/2" (the Waiex is really a "Y" tail, not a "V" tail)
3) There's less than a 1/2 a degree difference between the chord lines of the wings.
4) The flaps (retracted), left and right, have a significant discrepancy ...~1.5 degrees.
5) The tail feather control system is sloppy but symmetrical.
6) He has a (left) trim tab taped to the stub rudder (IMHO: it's bent so far that it's creating more drag than control force).
7) One of the gear leg fairings has a significant twist. It could be pushing the nose left a little at high speed. (trim problems are amplified with increased speed)
We've got more investigation to do (my money is on a sloppy mixer adjustment) but it's a bit of a mystery. We'll sort it out, but I'd be a fool not to enlist the free brain power of experienced HBA members.
we've lasered, tape measured, and micrometered just about everything we can think of (we still have to look at the control mixer, ...to fix the control slop if nothing else)
the short guy in the middle is our chapter "Yoda". ...when Bill speaks, people listen (the young guys won't get the joke) :gig:
I welcome anybodies 2 cents...
Fritz
He reports:
1) The nose goes right when he takes off.
2) But... he has to hold a bunch of right rudder at cruise. (high power, high speed)
3) The rudder pedals are neutral during a reduced power decent. (lower power, high speed)
4) He has to hold left rudder when the power is off. (low power, low speed)
...before you say "it's a thrust line issue", the thrust line is 'dead nuts' perfect per the plans, and a gazillion Sonex/Waiex's fly fine with the "per the plans" thrust line.
We've found:
1) The thrust line is dead on (per the plans).
2) The tailwheel and stub rudder are way out of alignment. ...~1/2" (the Waiex is really a "Y" tail, not a "V" tail)
3) There's less than a 1/2 a degree difference between the chord lines of the wings.
4) The flaps (retracted), left and right, have a significant discrepancy ...~1.5 degrees.
5) The tail feather control system is sloppy but symmetrical.
6) He has a (left) trim tab taped to the stub rudder (IMHO: it's bent so far that it's creating more drag than control force).
7) One of the gear leg fairings has a significant twist. It could be pushing the nose left a little at high speed. (trim problems are amplified with increased speed)
We've got more investigation to do (my money is on a sloppy mixer adjustment) but it's a bit of a mystery. We'll sort it out, but I'd be a fool not to enlist the free brain power of experienced HBA members.
we've lasered, tape measured, and micrometered just about everything we can think of (we still have to look at the control mixer, ...to fix the control slop if nothing else)
the short guy in the middle is our chapter "Yoda". ...when Bill speaks, people listen (the young guys won't get the joke) :gig:
I welcome anybodies 2 cents...
Fritz