My very heavy wing
 

I just finished phase I on my RV 7a. Had a very heavy left wing, full right trim still rolled left. Incidence checked great. Re rigged all control surfaces which actually made the problem worse. Several small squeezes and flights and after 5 tries got it perfect. It how's flies hands off. The squeezes where so small that you can't even see where I did it.

That being the case, I strongly recommend that before you do anything else, you look at section 5.7 of THIS document and evaluate the shape of your flaperons, and correct them (based on the instructions provided) before doing anything else.

There is probably a lot of RV-12's flying that don't actually have the handling qualities the RV-12 is intended to have, because the shape of one or both flaperons is not correct (besides the strong effect it can have on roll trim).

Here's what my trim tab looks like.

http://tinypic.com/view.php?pic=zko38n&s=8

Heavy wing saga
 

So.... I went out to the hanger this morning determined to make some progress with my heavy left wing problem. I read all the ideas, tips and images posted by fellow builders. Read the document that Scott had kindly referred me to.

I have to say I wasn't optimistic because this was a very heavy wing and I was convinced that there had to be more to it than tweaking the flapperons. I examined the skins and at first noticed that some were not flat at the trailing edge but most were close - until I checked the bottom skins! I must have been lazy and not payed proper attention to them because there were many that had a significant gap especially on the heavy wing.

I went through each panel top and bottom and squeezed them with the tool shown in the Van's document. I could get most very close but sometimes getting one side perfect meant the other side open a little mid skin. Anyway, after doing both flapperons I did a quick test flight. BIG TIME DIFFERENCE! I still have a slightly heavy left wing but no auto slow roll. Where the stick would displaced 2 inches to the left, it's now almost not noticeable from vertical. Hands off it will still start a slow left turn but takes very little pressure to hold the wing up. From the cockpit where I could easily see the flapperons displaced they now look even.

So the bottom line here is once again when things don't seem right go back to the basics and read the book. I'm amazed at how much a small adjustment can effect the wing but now optimistic that if I keep at it I'll be able to get this balanced without the aid of a trim tab. I'll post on how this turns out for those interested.

Bill

Bill, one tiny tip - -
 

I have mine set so there is a very slight left turn BY MYSELF. With a 200# passenger, it slightly turns to the right. That is where I ended up, and like it. If I take my hands off, by myself, you have to look closely to see it slightly turn, so no big deal to me.

Just to provide a point of reference, I probably adjusted my trailing edges 6 or 7 times to get it just right. First, I would do what Scott suggested and read up in the manual about it. Second, make small adjustments and go fly. It will take multiple iterations. Sometimes, you may go too far. I even blunted the trailing edge with a board and hammer :eek: to get it back. You can get it the way you want it but it's going to take some trial and error.

I found the best technique for bending the trailing edge is to take two long (approx. 6') 1" X 4" boards and install some hinges along the joint line. You are less likely to introduce a kink this way and you will get a more consistent bend.

I used a couple of pieces of alum angle from Lowes Aircraft supply. 1.5"x1.5"x6' duct taped together. It seemed to work great was light weight and cheap. Of course, I'm not flying yet! :D



Bob

This is an old thread, but after a tree fell on my hangar and damaged the flaperons, the flaperons were repaired. I had a pronounced roll to the left. I took it back to the shop that repaired the damage and they re-rigged the flaperons according to the plans. However, I still have a left roll issue.

RVBuilder2002 posted this: "That being the case, I strongly recommend that before you do anything else, you look at section 5.7 of THIS document and evaluate the shape of your flaperons, and correct them (based on the instructions provided) before doing anything else."

The link no longer works and his post doesn't identify "THIS" document.
Does anyone have a link or identify the document?

See Section 5.7 starting on Page 9 or so:
https://www.vansaircraft.com/service...d-revisions/5/

Well, ya-know, the pilot sits on the left side. That in itself is going to make the plane roll to the left. I realize that the -12 doesn't have wing tanks, but in my Lancair, I always fly with 5 more gallons in the right wing to counteract my 250 lb. weight.