Full left aileron trim to fly level.

How to fix?

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Comment by David Krakowsky on June 5, 2018 at 4:59pm
Comment by Dick Miles on May 21, 2018 at 11:11am

Bob & David thank you for your answers.


The engine is an O-235 Lycoming.

Do not know top speed as I have flown it very little so far.

Comment by Bob Pustell on May 20, 2018 at 5:45pm

By any chance does it fly any differently (in terms of aileron trim needed to stay level) with a tiny bit of flaps extended? I had flying rights in a friend's 601XLB until he sold it. The plane had a heavy left wing that you always needed to hold a bit of aileron against (no aileron trim). However I found that if you just touched the flap switch to just barely extend the flaps the heavy wing went away and the plane flew straight. Close examination found that one flap was hitting the up limit stop (the nylon stop out on the wing, not the electric up stop on the motor) before the other flap hit it's stop. That caused the flap that hit a stop first (the right wing flap) to be making a bit of lift when the flaps were stowed, lifting that wing and causing what seemed like a heavy left wing. The plane actually had a light right wing, so to speak.

There was enough flex in the flap actuating system to allow both flaps to hit their up stops, but one wing's flap was stopping just before the other wing's flap did, causing uneven wing lift when the flaps were fully retracted but even lift when the flaps were deployed even the tiniest little bit.

Your plane may or may not have the same issue, but this is a good example of how something obscure can cause a symptom. In my case a flap stop problem appeared to be an aileron rigging problem. Who knows what your problem may turn out to be but do not limit yourself to the ailerons in looking for the problem. Good luck.

Comment by David Krakowsky on May 15, 2018 at 1:15pm

Last first, yes air vents can be added to canopies. I have them in mine.

nexr time I go to the airport I’ll take a pic for you. Very easy to damage the

canopy if you don’t know what you are doing when you install them.

Trim problem, are you sure it’s not a weight imbalance? These planes are

very light and flying solo will cause a trim imbalance, I always have a full tank

on the right when flying solo and use the left tank first.

if you don’t think that’s the issue I would get out the plans, if you don’t have them, 

buy a set and check the rigging of the aircraft. Something is probably off, and you need to check it all.

lots of aircraft have a bendable fixed trim tab to make the plane fly straight, that’s not fixing the 

problem , just covering up the symptoms.

What engine do you have and what’s your top speed?

an out of trim aircraft is usually slower due to increased drag.

as far as your statement about your aileron, it may be normal, check the plans on

how to check the ailerons.


Comment by Dick Miles on May 15, 2018 at 10:48am

Can vents be added to the canopy?

Has anyone done it?

If so, could you provide photos?

Comment by Dick Miles on May 15, 2018 at 10:25am

It was built in 2005 and modified to a 601XL-B in 2009.

I bought it from the builders estate. 

The builder was a college professor, PHD aeronautical or electrical  engineering.

It was in this condition when purchased, that is, taking full left aileron trim to fly.

The ailerons do not match up with the up flaps. Actually,the right aileron is higher than the left aileron when the left is matched with the flap.

I cannot believe the bullder flew it this way, in fact the individual CFI I am flying off my two hours for the insurance company had flown with the builder several times and said it was not in this condition. I have only flown it 45 minutes with the CFI to date.

Comment by David Krakowsky on May 14, 2018 at 4:11pm

I think we need a lot more info to help you.

is it a new build?

did it suddenly change?

give us some history of the aircraft.


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