CG Range of the Riblett 30-612 airfoil

[jarheadpilot82]

To the Forum members-

I am not building or flying a Kitfox, but I was wondering if I could possibly get some information from you.

I am the moderator of a forum that is for builders and flyers of the Pietenpol Air Camper and specifically, Pietenpols that are powered by a Corvair engine. Many of our builders are moving away from the original Pietenpol FC-10 airfoil and using the Riblett 30-612 and 30-613.5 airfoils.

It is my understanding the the later model Kitfoxes use the Riblett 30-612 airfoil. Am I correct on that? My question and the purpose of the post is this-

for comparison purposes only and as a point of discussion on our forum, I was wondering what the recommended CG range is for that airfoil when used on a Kitfox? I am not looking to stir up the pot, so to speak, or get into a discussion. I am simply looking for that bit of information. Does the factory recommend a CG range? If not, how did you determine the range? What do you use for a range?

Any help and information is greatly appreciated. I hope that I am not butting in. I was just looking for some info from fellow builders, and want to say thanks in advance for any help that you might provide.

Semper Fi,

Terry Hand
Athens GA

[Esser]

C of G has more to do with how much weight your tail can manage. It also has to do with how dangerous you want it to be when it stalls. Extreme aft, the nose doesn't drop etc.

This is by no means professional advice and I'm not recommending any one change their wings out on a plane but I would say if the centre of pressure is the same location and the chord is the same size you are probably ok but I would verify with an aeronautical engineer.

[avidflyer]

I don't know what the Riblett number is supposed to be on the Kitfox 4 wing, but the Kitfox manual gives the CG limits as 10.7" (20.8 percent) MAC extreme forward and 14.78" (28.7 percent) MAC extreme aft. Those dimentions are taken from the leading edge of the wing. Jim Chuk

[jiott]

I am not sure about the Riblett number, but the CG range for the latest Kitfox Super Sport 7 is: 9.5" to 16.0" measured from the wing leading edge at the root. This is with no wing sweep.

[efwd]

The manual for my SS7 states that the airfoil is a GA30U-612. I have nothing more to add than that as I haven't or don't recall ever reading anything about your other questions. Maybe its discussed later in the Weight and Balance section.
Eddie

[jarheadpilot82]

Jim and Eddie,

That is a huge help. Thank you. I just need to know now the chord length on the airfoil and I can figure %MAC. The Pietenpol airfoil has a 60" chord.

Thanks!

Semper Fi,

Terry Hand
Athens GA

[jarheadpilot82]

Avid flyer,

I am sorry. I should have been more clear. I believe it is the Kitfox V, VI, and VII that use the Riblett 30-612. But thanks for being willing to help!

Semper Fi,

Terry Hand
Athens GA

[mr bill]

What number airfoil does the kitfox 4 have?

[desertfox1]

Hi Terry, This not as easy as it looks. Jim's numbers
Are correct but the chord length is the problem. The
Kitfox chord is 42" but it has a flaperon which also
contributes to the equation. It is a unique problem
to solve. I've heard 50" combined, but I don't know.
Good luck, always liked the Piet, had plans from Mr P

Phil Laker

[jarheadpilot82]

Phil,

I had heard the 50 inch number as well, but was looking to confirm. Thanks for the info!

Semper Fi,

Terry Hand
Athens GA