KF7 Airfoil?

[wadeg]

Anyone know what the airfoil is on the 7?

I'm interested in doing a bit more study on the airfoil and as related to my VG issues, where the airfoil needs them specifically.

Any aerodynamicists (which I am not) are welcome to get involved!

We might be able to resolve some of this confusion and mystery as to how well VGs work on the design and where specifically they need to be placed. Perhaps we can find out if any certified aircraft that have used VGs give us any hints to the 'sweetest of spots'.

[Esser]

I dont have it with me but look at the wing assembly instructions. The overview on the first page says what kind of wing it is but it does say its modified

[Timberwolf]

I have a degree in Aeronautical and Astronautical Engineering from Purdue and must say this may very well get way above your head in a hurry if you let it. If you are able to find out the airfoil, you may get lucky and someone in the past may have already run an analysis that may simplify things for you. Using a CFD program and running even a low order panel code takes quite a long time with an extensive knowledge required to even scratch the surface. If you are looking for rough numbers of subsonic airfoils, you can use a program called XFOIL that will allow you to calculate drag buckets for many of the airfoils out there today.

Remember though, this will be in reference to a 2-d object with a reynolds number that you have calculated.

Once you get into 3-D modeling and running CFD, you're talking a lot of hours for the actual modeling of the aircraft followed by hours and days for the computer to actually run the code.

So....with all of this, I would recommend just getting out there and doing some testing using tufts on your wings to identify the laminar and turbulent boundary layers(to an extent) and just what effect the VG's are having on the airflow across the wing.

This guy has the right idea http://www.youtube.com/watch?v=bIsWseMbDQU

[wadeg]

The airfoil may be a Riblett GA-30U-612.

And yeah! It already got over my head!

I'm finding stuff that indicates the Baby Ace had this airfoil.

[HighWing]

A close friend had a chat with Harry Riblett once. He reported that Mr. Riblett told him that the most critical part of the airfoil is the leading 10% of the chord. His comment then mentioned that in the Kitfox wing, not much of that had his design profile because the rib capstrips and false ribs are the only parts of the leading 10% that have the profile. The rest being pretty much a mix from his airfoil to the unknown airfoil created by the shrunk fabfic. I think the Laker Leading edge was an attempt to address that issue. I am still waiting for a report on VGs on the Laker wing, which is actually the Riblet wing. It has pretty much been my take, based on the earlier reports of minimal effect on stall with VGs. that the Kitfox shape already acts somewhat like VGs with turbulence created by the varying velocities of the air flowing side by side over the hills and valleys.
Lowell

[napierm]

These are pretty close. There is some averaging to account for fabric sag and they are not quite the same as the ribs (I measured). However, I'm not sure they will do you much good. The problem is that with the flapperons you are dealing with a multi-airfoil system and not simple flaps; the flapperons add effective area as well as change the airflow. XFoil won't handle it. There is a program by Mark Drela that may be of some help:

http://web.mit.edu/drela/Public/web/avl/

So many projects, so little time....




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