Kitfox wings on an Avid

[1avidflyer 1983]

A while back, there was a discussion about using Kitfox wings on an Avid. Someone mentioned why it would cause problems. I think it had to do with the incidence of the wings. I tried to find the post that talked about it, but couldn't. Maybe it was even on another site. Any remember it? Thanks, Jim

[EDMO 1078]

Jim,

I don't know the whole story on this, but it might depend on which Kitfox wing you use - IMO, the early KF are almost a perfect copy of the Avid, except 3 feet longer span. The KF4 and later should not put as much downforce on the nose, and you should need less up elevator to trim out for a faster cruise. At least that is why I am modifying mine to the later ribs - my Soob is nose heavy anyway, and I have the standard short fuselage.

EDMO

Edited 21 Aug 2013 by Ed In Missouri

[1avidflyer 1983]

Ed,  I was talking about the early wings  Model 1 to 3.  I had thought they were the same also, but someone had posted and told about the differences.  I'm trying to find that post.  Thanks,  Jim

[EDMO 1078]

Jim,

I would like to read that post. The only early change I know of was the KF2, and that was a change in the crossover tubes height that changed the incidence. If I could get to my KF1 copy which is hanging from a 13 foot ceiling over the area where I am working on my wings, I might be able to actually measure the differences in the KF1 and KF2 crossover tube heights - But right now, I cant get there.

I don't believe there is any difference in the wing ribs 1-3.

EDMO

Edited 22 Aug 2013 by Ed In Missouri

[Av8r3400 1179]

If you're going to put Kitfox wings on an Avid, why bother with the early ones and just go to the IV and later wing?  Far superior performance in nearly every aspect.  Especially if you can get the symmetrical flapperons, too.

 

If you are building them, you can use your Avid lift struts, if they are already built, you will probably need to build your own lift struts.

[1avidflyer 1983]

What got me thinking about this is I need to rebuild some Avid wings. There are a couple of Kitfox 3 wings for sale for what I think is a resonable price. I know someone recently posted a message explaining what was different about the wings. I knew about the difference in the lift struts, but there was something else mentioned and thats what I'm trying to find out. I think it was the incidence of the wings, but I'm not sure. Jim

[Av8r3400 1179]

I posted that. The incidence is different in the 1-3 Kitfoxes, but the wing construction is the same. It wouldn't be a factor in this type of project.

[1avidflyer 1983]

When you say the incidence is different, would one have to mount the Avid horizontal stab. at a different angle to ovecome this?? Thanks, Jim

[EDMO 1078]

Jim, I don't think you will find very little difference - I am talking about 1/4 or 3/8 inch on the spar attach. Don't think it is enough to worry about HS - The later models have an adjustable HS, and all that does is give less deflection of the elevator to trim for cruise, IMO.

EDMO

[EDMO 1078]

Jim, and anyone,

If you are thinking about buying the undercambered Kitfox wings and converting them to the Kitfox 4 modification I have made, I may be able to supply you with laser-cut spacer webs. I am going tomorrow to talk to the cutter and see if they are reasonable. I'm not trying to make any money on these - just cost of plywood, cutting and postage, if you are interested.

EDMO

Edited 23 Aug 2013 by Ed In Missouri