Used airplane- Heavy Wing, suprising solution...

[jcmcdowell]

what can I say-

before: ball off center, 10lbs right aileron force to maintain level flight

after: ball centered, 2lbs right aileron force to maintain level flight
(it was like flying a whole different airplane)

no other adjustments made, no 'apparent' loss of ground speed. It wouldn't have been my first assumption (ailerons, wingtips, fairings). I would categorize this as 'gross' tuning not fine tuning (ailerons, wingtips, fairings).

If this gets me 80% there- I'm satisfied.

I will keep you posted, however, if the other adjustments result in an overcorrection to trim or yaw.

[coastalflyer]

As a little side note, when you are flying wings level with the ball centered you are actually side slipping a little (with power on) due to P-factor. Your heading doesn't change, but your track does. I know this from flying a turboprop with two 1800 HP engines and both props spinning clockwise. You fly that thing with the rudder trim. Best aerodynamic efficiency is achieved by banking into the p-factor slightly, and actually your butt will tell you that. If you listen to your butt that is. I like to listen to my butt.

[David-aviator]

Aside from all the information on this thread, has anyone come up with a rudder trim system?
With the wide speed range of these airplanes, rudder trim would be nice.

[kentb]

Originally Posted by David-aviator

Aside from all the information on this thread, has anyone come up with a rudder trim system?
With the wide speed range of these airplanes, rudder trim would be nice.

I have seen pictures of it, on this site I think. He used an elevator trim motor mounted in the rudder. I move a length of hinge back and forth to effect the rudder.

Kent

[hecilopter]

Reading thru this has been interesting. The thing I don't understand is that RIGHT aileron was needed to hold the plane level. To fix this, the leading edge of the vertical stab was moved to the RIGHT to center it (as seen from the rear, it was offset to the left per plans to start with).

The reason the leading edge of the vertical stab is offset to the LEFT is to add the effect of RIGHT rudder. By moving the vertical stab to the RIGHT, it would seem to be the same as adding LEFT rudder, thus compounding the initial problem of rolling to the left.

Am I thinking correctly on this?

[videobobk]

Originally Posted by David-aviator

Aside from all the information on this thread, has anyone come up with a rudder trim system?
With the wide speed range of these airplanes, rudder trim would be nice.

I was parked behind a 10 with rudder trim at Osh. It was basically an elevator trim system mounted into the right side of the rudder fairly low. The actual trim tab was on a hinge and was 8-10" long and about 1 1/4" wide. It looked to me like it would take very little movement of the motor to make a large change in the angle, but with the small area of the tab, it might be about right. I think it would be a nice addition. My 9A centers at 150-160 mph and takes left rudder above that and right below.

Bob Kelly

[Mike S]

http://myrv10.com/tips/mods/RudderTrim/index.html

This is from the -10 forum.

It is still on the front page, should be easy to find.

[GrayHawk]

Originally Posted by hecilopter

Reading thru this has been interesting. The thing I don't understand is that RIGHT aileron was needed to hold the plane level. To fix this, the leading edge of the vertical stab was moved to the RIGHT to center it (as seen from the rear, it was offset to the left per plans to start with).

The reason the leading edge of the vertical stab is offset to the LEFT is to add the effect of RIGHT rudder. By moving the vertical stab to the RIGHT, it would seem to be the same as adding LEFT rudder, thus compounding the initial problem of rolling to the left.

Am I thinking correctly on this?

My thinking matches yours. I bought a flying RV-6A and have been working on the alignment. The plane had a large aluminum trim tab on the left side of the rudder, to give roughly straight flight at cruise. When I got to the empennage checks, it turned out the VS actually had RIGHT offset (the 6 was originally spec'd at 0 offset). After consulting with all the experts and everything else I could lay my hands on, I corrected the VS offset to approx. 1/4" LEFT and took the rudder trim tab off. Plane now flies straight at cruise and is 8 mph or so faster. In my case, RIGHT VS same as left rudder, which was then counteracted by left trim tab (right rudder). Moving the VS LEFT acted as adding RIGHT rudder & trim tab no longer needed. Clear as mud, right!

Rudder control feels much better too.

[Bryan Wood]

Danny Parker from Livermore, CA came up with a very nice inflight adjustable trim tab on his rudder. If you have desires to do one of these he is the guy to contact. Anybody from Livermore on the list that can get a hold of Danny or shoot some pictures of his rudder?

[fodrv7]

Morning all.
Lot's of interesting Post whilst I was sleeping.
Interesting what you can miss. My brain missed the Left Right thing.

A mate has a PERSPEX rudder trim.
Clever bit of engineering.
It is long and rather thin and quite curved.
So at low speed it is sticking well out into the breeze, but bends back in trail at high speed. It works. Lots off rudder trim applied in the climb and not so much on the cruise.

If anyone is interested could take a pic of it.
rvseven@bigpond.net.au.

Pete.