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n38139

Well Known Member
I have an RV-8 that will really roll to the right at slow speeds, flaps up or down. In high speed cruise it is not much of an issue. I did not build the airplane. Does anybody have any comments?

On another issue, I flew it for the first time today with my new TMX O-360 and new Hartzell. Hang on Baby!!!!!! :D what a difference over a O-320. When I took it up for stall test, it almost won't stall. As soon as you release back pressure, it starts flying. It is a little nose heavier but I am really happy I did the swap. As soon as I get the roll problem solved, I will have a sweet ride.

thanks,

Steve
 
Check your flaps

Years ago at a regional fly in an airline pilot came up to me while i stood by my 6a and told me he had about the same kind of problem. I said "let's go have a look" and once at his rv it was easy to see that with the flaps retracted, one of the flaps was 1/4 inch lower that the other. I showed him the flap link and how to make the adjustment. Problem solved. Don't know if that is your problem or not? but take a look. If that isn't the problem, then you will need to do the "aileron trailing edge squeeze" trick. The post above will most likely direct you to it.

steve ciha
 
Heavy aileron due to it not being flat...

Some time ago, I damaged an aileron and need to replace it. I got a quick build one from Van's. I got it put together and on the airplane and when I took off, it wanted to roll right in a big way.. 3 pounds of pressure. I checked the hinges twenty times and went through a few trying to get it right, but with no luck.

Eventually, I had an expert builder look at it. He told me that if the ailerons are not precisely flat on the bottom, or at the very least an exact match on both sides, then you will have a heavy wing. I asked him to build me a new aileron which would be perfectly flat on the bottom. When I put it on, it flew hands off first time.

This cost me in a big way, but it was worth it to get it right.

Hugh.
 
check your flap link

Hi there,

The link I spoke of is a threaded piece of aluminum tubing that connects the flap to the actuator arms. It will have threaded rod end bearings at each end.
It should be visible when the flaps are lowered.

steve ciha
 
Oh! That Link

OK now I feel like a real moron. I should have read your post a little closer. I acutally did check the flaps today but they were very close. I am going to look at the aileron surface issue. I knew the airplane had this problem when I bought it. The previous owner tried several things including raising the leading edge of the aileron by changing the mounting bracket. He said that somebody at Van's told him to do it but it really looks bad to me. I have also purchased a aileron from Van's to try that but that may not fix it. I won't give up until it flies like my RV-4 did, hands off.

thanks for the input.
 
check for wing twist

If the amount of wing heavyness changes with speed, most likely the wing is twisted. Level the plane and carefully check the incidence on both wings. If one wing has a difference in incidence you can drill the rear spar attach bolt to 3/8" if you maintain minimum edge distance. If one wing has a twist you have a problem. The only solution is to remove skins and rejig the wing and install new skins. Not fun. Good Luck
 
Another comment regarding the flat ailerons comment earlier.

I tried moving the brackets up and down on both sides to try to fix my right turning tendency. It did little or nothing. So bottom line, put them back to being the same on both sides. Its a good place to start from.

Then, check the flat surface of the ailerons to verify they are absolutely flat. If its not flat when lying on a flat table at both the leading edge and trailing edge (so that it does not rock or move), then you need to fix that first.

I got Henry Gorgas to build me a new FLAT aileron. Henry gives classes in building RV's and has solved this problem twice now for two different people. You can get his number on the vans site. I highly recommend talking with him, although he may not be happy I sent you...:)
 
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