Aileron trim questions?

[Buckaroo]

Today went flying and noticed my aileron indicator full right. Adjusted it to the center and immediately felt the stick slammed full left. So I guess the indicator is faulty. I eyeballed the ailerons even and went flying. I decided to take some pictures so I engaged the autopilot. About 20 seconds into nice level flight the plan started a increasing roll to the right. I could hear the auto pilot fighting to bank as it would click and I could feel the stick adjust.

 

Any ideas of this situation? The auto pilot is new to me so I may be missing something simple. Also a fix for the indicator as well.

 

Thanks all!

[Roger Lee]

The indicator has slipped on its string. I tell people you don't fly the indicator. You move the wheel to where ever it is trim regardless of where the indicator is. Most of the time if you look at the rudder the top front tip is facing a tad left about 1". Once trimmed you can if you want slide the indicator back to the center, but don't move the wheel. It it is hard to slide do not force it or you may break the string it's on. If need be you can reach down inside the slot with a small set of needlenose pliers and grab the base of the indicator and unscrew to loosen the chrome top part. Then move it over and then retighten the indicator. There shouldn't be a time when the trim wheel needs to be full left or right. My indicator used to be just right of the center mark, but who cares because you turn the wheel to get the trim and don't care where the indicator is. That is only a quick eyeball reference.

[Buckaroo]

Ok Roger understood and thanks! So pre-flighting should I make sure ailerons are even, stick is centered, nose wheel is centered, rudder is one inch left, elevator is centered while stick is centered??

 

Why was my AP banking right? I thought I turned it on to track straight but maybe it was seeking a rearward gps input???

[cdarza]

. Most of the time if you look at the rudder the top front tip is facing a tad left about 1". 

This helps.   I always thought something was wrong if i had to trim rudder this much out.       I have seen other aircraft (not CT) with a fixed metal 'tab'.  Is this something that can be done on the CT to counter the left yaw 

[Buckaroo]

Rigging this plane is all of a sudden interest to me! Honestly three trim adjusters has fallen to the last prioritys for me to learn with respect to this aircraft! With known weak adjuster indicators it will now be important that I check the alignment of the three flight components from the outside of the aircraft during pre flight.

 

Question: should the stick be positioned centered and then the preflight conducted with observance to the control positions and if not even or rudder 1inch left be adjusted by the trim wheels?

 

On one recent flight I noticed the rudder ball way right and had a alarming few seconds wondering what was going on. The trim although indicator centered was giving a false indication.

 

When I fly the turn coordination indicator is even more valuable than the airspeed indicator!! My CTSW is challenging me with this every flight in a good positive learning way! ????????

[Roger Lee]

You're overthinking your trim. Forget about trim on a preflight.

If you want to set up the trim and not be cross controlling set each trim back to a more centered position. After you take off set the pitch first to help remove the stick pressure. Then set the aileron trim and then the rudder trim. If you have done this right then your plane should fly hands off. If you want to fly 1/2 ball out to one side to help equal fuel usage then trim for that 1/2 ball out after all three trims are set up.

Many time once trim is set you don't need to do this every flight. I usually only have to trim for neutral pitch.

[cdarza]

This is trimmed full.  Would this be considered too much deflection for cruise flight?

[Anticept]

The only time trim is "too much deflection" is if it causes to to exceed the full deflection spec. Which would be crazy.

[Anticept]

There is a rigging specification in the manuals. If SOMEHOW your trim managed to deflect the rudder more than the spec, that would be a problem.

 

Rudder trim is basically spring loaded. Very simple design, it's almost silly that there are even indicators for it.

[cdarza]

Like this ?   (Full trim and full deflection)  I have not measured, but this looks awfully too much deflection

[Anticept]

That's probably at full deflection.

 

That said, I never mentioned anything about applying rudder AND trim. There is no prescribed limit for that. When rigging, it's done with trim neutral.

[Roger Lee]

The trim on the ground is not the same as in the air. You have air stream forces at work up there.

Don't overthink or overly worry. Just set the trim to be hands off in the air. You will over think this make wrong interpretations on the ground and try to make an adjustment then you'll really have an issue. If your plane trims up then leave it alone. Don't make a problem where there is none.

 

Hi cdarza,

 

The first pic where it is out about 1' - 1.5" is is pretty normal, on the ground, but may not look like that in the air.

[cdarza]

Thanks for the inputs.  Yes, i did not think about the airstream that pushes the rudder back in a little thus the rudder is not that far out when in the air.

[Runtoeat]

Wouldn't most of us see that our rudders will have a small amount of right bias due to the need to put in some trim for offsetting "P" factor produced during cruise?  I note my CT will have a small amount of right rudder after I land and get out of my plane. This is after my flight was made with all trim set to "neutral" flight.

[cdarza]

Yes, that would be the assumption.  It is good to confirm that through this thread.    However, just for conversation (and i will take Rogers advice not to over think this trim) Wouldn't it be another option to place a fixed rudder 'tab' to offset the pfactor.?  Quite common on most other aircraft.  

[Anticept]

Many single engine aircraft have an engine and prop that aim slightly to one side, as well as a vertical stabilizer that is also off axis. That's to counter slipstream and p-factor in cruise.

[Runtoeat]

Cdarza, the rudder was increased in size after 2005 to provide added "rudder authority" to our CTSW's.  Even though a small amount of the right rudder travel has been used for trimming, I still have adequate rudder control during crosswind landings.  IMHO, I believe that our infinitely variable trimming method is robust and a preferred way, compared to a bendable trim tab (which can be bent unintentionally) that provides only one selection for trim once set.

[FlyingMonkey]

I get my airplane trimmed for straight and level flight at typical weight and balance, basically me solo and 20-30 gallons of fuel and all the stuff I normally keep in the airplane. After that it's very rare that I touch the trim. If I'm flying with two people for a long trip it might like a slight aileron trim ajustment, maybe 1/8 to 1/4 turn. And it might take a little rudder trim to manage fuel between tanks for short periods on long legs.

 

Other than that, I set the trim where the airplane flies straight and forget it (other than pitch trim, of course). my indicators are both slightly to the right for bothe aileron and rudder. That's just a reference, unless you are close to full deflection on an indicator peg, I would not give its position a second thought.

[WmInce]

Cocur with you Andy, with one exception.

After a day of flying, I zero out the trim to relieve any tension on the cables.

[FlyingMonkey]

Cocur with you Andy, with one exception.

After a day of flying, I zero out the trim to relieve any tension on the cables.

Zero it to where? As Roger said, the peg position amounts to little more that a reference position, and should not be taken to mean absolute zero of the trim system. That being the case, you can't be sure you are not *introducing* cable tension by altering the trim. All cables are under some tension anyway, it doesn't hurt them. I'd guess the least amount of tension on the cables would be where the airplane flies straight. Your method requires you to retrim the airplane in all axes during every flight, which seems unecessary.

 

I think ayou are overthinking this...set it and forget it!

[Runtoeat]

This would be  good poll.  How many of us are "set and forget" fliers and how many are "frequently adjust" fliers for the different stages of flight (i.e., takoff, landing and cruise)?.  FWIW, I'm in the "set & forget" camp. Once I have trimmed my CT to fly "neutral" I rarely make further adjustments for the different stages of flight.  I'm thinking the current or retired commercial/military pilots might be in the "adjustment camp"?

[Roger Lee]

I'm a set and forget except for pitch.

[cdarza]

I only use the pitch.  I have always kept the rudder in the center position (eyeballing it on the ground and not the trim wheel indicator) and thus i usually had a left yaw and had to keep a little right foot pressure on cruise, which gets very tiresome.   I shall set the rudder trim on my next flight and finally forget it   

[WmInce]

I'm thinking the current or retired commercial/military pilots might be in the "adjustment camp"?

That's a valid point, Dick. Those are where my roots are.

That's my story and I'm stickin' to it.

[Doug G.]

Set and forget except pitch, and occasionally yaw to transfer fuel.