Springer, what do you want to be stopped from doing? You going on a building binge?

Roger

My bad, should have given attribution for the comment. It was Jim Carrey in "Mask" when he was going to do something crazy anyway as the Mask. (loved that show!) And it was pointed at gpw's "just have to build it and see" comment!

Spring, we've done crazier things than this before ... some even worked !!!

Yes, of course, But were you wearing a magic mask that made your face green???? Oh, boy, going off topic again!!!)

Any ideas on how to incorporate a Kfm on a profile f-22? I'm doing a 200% and think the extra lift and stability would help. Thanks

Originally Posted by frednjess

Any ideas on how to incorporate a Kfm on a profile f-22? I'm doing a 200% and think the extra lift and stability would help. Thanks

You're building a foamie with an 89 foot wing span? Wow! I know you did well with the Giant Flying Wing but that would be a nine fold step forward.

At any rate, time and experimentation as proven the KFm4 to be the best of the KFm's for speed and maneuverability, imagine this:

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Two 50% or so KFm strips sandwiching a center panel. The multiple layers leave you a lot of options (filament tape, CF tubes, etrc.) for spars between the layers.

Using more steps and lower steps is showing a lot of promise on builds like viking60's Dancers and davereap's A-clone and W-clone slope gliders and more layers might let you laminate in more strength.

Will this have a prop?

Jack

Yep, 89'. I tried to get a waiver approved from the AMA but that didn't happen. Told 'em to suck it and doing it anyways!
Dick Kline had suggested that the KFm4 is a better design. Just trying to incorporate it into a flat plate airplane is actually making me think. Terrible, I know. And yes, this will be a mid mounted pusher prop design. http://rc.tomhe.net/f-22
That super wing is still flying. I like to bring it out to freak people out, especially at Giant Scale events. Had one guy tell me I couldn't fly it at the event. I told him my plane was bigger than 90% of the "giants" at the event! Eventually he caved.

A number of people are using a KF airfoil on profile F-22s. Here is a link to one: http://www.rcgroups.com/forums/showp...&postcount=403

Roger

I'm using FFF on most of my builds so leaving the factory folded edge intact between two sheets of FFF and inserting a wing center panel in the "taco shell" makes for one of the fastest and best builds I've found yet. Instant KFm4 wing!

And if you can already fly and have higher expectations for performance, the KFm4 can be really pleasant in the air. It flies very nicely either side up, handles speed well, and still slows down very nicely without getting the least bit unstable.

If no one has tried steps on a F-22 yet I'd start with a couple of lower steps. Look at this thread and it will give you some ideas as to the number of steps, step heights, locations, etc.

http://www.rcgroups.com/forums/showthread.php?t=1391999

Those planes are flying very well and I'll bet if you scale some of the concepts seen there up it will work.

Jack

It is the KFm9 airfoil which was developed by Dave Reap. How does it perform? Have a look...

The Twizzle KFm9 Pitcheron off Greatstone dunes uk (8 min 26 sec)

Y'all need to move this discussion of building over to the build thread, eh?

So has anyone thought to do Schlieren photos of KFm profiles? I would think it would hold a world of insight and be more effective than building models in helping to understand how the steps affect airfoil behavior.

Siliconserf, A number of fluid visualizations have been done, but they are all at Reynolds Numbers for full scale civillian and military aircraft. Schlieren photos would be great. The only problem is that you need a wind tunnel. If we had one available, we could do Schlieren and smoke visualization. We could also get lift and drag data.

Do you know of a wind tunnel that's available?

Roger

Wish I did. At this point even a smoke generator and a house fan would look good. I was hoping someone had done at least a Wright Brothers style box.

Guys , no wind tunnel ??? Years back we made a wind tunnel from a washing machine box (cardboard) , with some egg crate style "flow straighteners" inside ... The box almost exactly fit an old box fan we had , and we'd suspend the plane ,with a string attached to the CG , behind the box and "fly " it that way ... Sorta' a "crude " flight simulator ... Worked !!! It would be easy to makes something like that for KF testing at "realistic" model airspeeds... Paint the inside black , rig a light on the airfoil only , small hole in the side for a key chain camera... Blow in some smoke !!!! You can't test the lift , but you sure could capture the "flow" for all to see...
So who'll be the first to photograph the various KF airfoils at Model speeds ...??????