My extra and decathlon both have a lot of coupling involved when trying to knife edge. The extra more so than the decat. My question is can I mix the elevator and ailerons in slaved to the the rudder so that when I apply rudder for knife edging, it holds it without extra input. I know it would probably require lots of landings and adjustments, but I think it would be worth the trouble to just use one stick for the knife edge.

Garcfield, how much of this is done in IMAC?

YES it is a good idea to do this. I use a switchable mix and start by mixing the elevator correction only. I have also mixed the aileron correction in the past for pattern stuff but on my 3D models don't bother with the ailerons.

3 to 5 flights usually gets it done.

BUT not doing it is also a good idea at least early on in your flying career. If you learn to compensate for all these problems by flying all 4 axis on the box, then dealing with diversions from the intended flight path become automatic reflex actions.

I'm just the opposite, I prefer to fly the knife edge without any compensation from the radio. I feel that I have better control over what the plane is doing if I am doing it myself instead of relying on the radio.

Ken

Brett, have you gone completely though a trimming chart?

http://www.rcaerobats.net/trim_chart.htm

A lot of times the couplings can be removed from other adjustments. I use mixes as a last resort for this reason: say you use a mix to fix your knife edge coupling, which will be slaved to your rudder. Every time you use your rudder (unless its a switchable mix) you will be using the mix. Maybe you don't want elevator and ailerons when you do a stall turn? I'm not saying not to use a mix, but go over your plane with the chart and see if there is another correction that needs to be made.

There is no knife edge flight in the first two classes of pattern or IMAC.

Nice link, thanks. I was really wondering more about how much mixing is used in pattern and IMAC, not really if a knife edge is used. I know a guy at our club that flys IMAC, and he always throws his plane into a knife edge right at takeoff. He flys giant scale, and goes to all the big meets, Greg Ward I think is his name.

Mixing is used a lot in competitive flying. I think everyone has some form or another of that same trim chart and once the plane is set up it gets mixed to the pilots liking, usually dependent on the schedule he will be judged on.

Brett, what Decathlon are you flying? Like it? The Decathlon really is one of the prettiest planes IMO.

It's a seagull decathlon. It was hanging in the LHS, and I wanted it as soon as I walked in the door! You're right, its one of the prettiest planes around for sure. I like scale high wings a lot. It's a handful in the air, but well worth it. Everybody loves how it looks when I do a knife edge down the field with the wings facing us.

Absolutely beautiful I had one and sold it, and it is kind of painful every time I see it at my buddy's house. Just wasn't the right plane for me at that time and I will definitely own another one (probably when I have a vehicle big enough to transport 2 planes at once). What do you have for an engine?

From what I can see from that Extra I would guess it might need a little mix for knife edge. There is not a ton of rudder 'meat' below the thrust line. I bet it pulls to the canopy and rolls a little in the same direction? Just a guess...

Nice planes