The Cessna 120-140 Association Forum

I have been giving some guidance to local A&P not familiar to our 120/140's while he does an annual inspection; owner of the 140 has passed away and family is giving it to a grandson.
This evening I had an opportunity to preflight the 140, and I noticed that the ailerons are not in the neutral position as are those on my '46 120.

The wings of the 140 have been metalized.

With control wheel in neutral position, both ailerons droop; right aileron more so than left.

With left aileron in neutral position as described in rigging controls section of our reference manual - contour of the flaps, the right aileron droops approximately 5 to 7 degrees.

Since I am not familiar with metalized wings on a 120 nor 140, I am respectfully requesting comments if the above mentioned condition is something to do with wings having been metalized.

Thank you

L. Benson

I doubt it is related to the metalizing process.

Without going through the whole rigging procedure, it's hard to tell where the "mistake" is. If when the yokes are centered the bellcranks are also centered, then the ailerons can be adjusted by shortening or lengthening the pushrods.

IIRC, tightening the carry-through cable will raise both ailerons equally.

Metalzation is not the cause.....poor rigging is. I just re-rigged mine and it was straightforward but time consuming. Procedure is available online. And in manual....

Jon

A lot of crop duster guys droop their ailerons some, in an attempt to shorten takeoff roll and they think they can carry a heavier load. What they get is an airplane that is heavy and slow in roll.
What you want is ailerons that are slightly reflexed, that is when in flight they are raised about 1/4” or so. If there is any slack in the system and of course there always is, ailerons will float up in flight on their own, so often if perfectly aligned on the ground, in flight they will be raised somewhat, this is fine, don’t droop them in the attempt to have them aligned in flight.
Ailerons being reflexed also washes out the wing somewhat and in a stall will help keep the tips flying which will still give you aileron control and keep a wing from dropping in a stall,with the ailerons drooped, you could get a tip stall, and of course that’s bad.