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  • December 16, 2018, 09:31:15 AM

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Author Topic: Egad .  (Read 355 times)

Offline Matt Spencer

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Egad .
« on: November 23, 2018, 07:33:40 PM »


Was actually a similar airfoil on a Wight , pre WW 1.

This is one of theirs .or two .


If one wing is good , four must be gooder .



Is actually a book on them , and their experimental work . hence the Airfoils . I think in the Takapuna Library .

Think they were absorbed by Pemberton-Billing, & thus became Supermarine .


Online phil c

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Re: Egad .
« Reply #1 on: November 27, 2018, 11:46:16 AM »
This idea originated back in the 60's for paper airplanes.  They even patented it.

More recently the flat foam RC guys have tried it.  A single flat sheet of foam works fairly well.  But try and make it turn past a critical point it just quits working and the plane is barely flying until the angle of attack gets reduced.

Dick Sarpolus and I tried this out at least 30 years ago.  He built a couple CL planes, the same as a flat foam RC plane he called the Too Windy.  I cut the cores for it, a pretty slapdash, fairly sharp leading edge wing.

Whether CL or RC, they both had the same problem.  Try to turn too tight and the plane stalled and quit flying.  It wasn't a huge problem on the RC version, just keep the speed up and if needed back off on the elevator. 

The CL plane was severely limited.  It could do large, smooth eights and loops, but any kind of corner the plane just stopped turning and I had to back off on the controls to get it working again.

With the foam wing, the exact same size, it made a pretty nice little sport stunter. It could do all the maneuvers in the CL pattern.  The maneuvers with a turn of sharp radius didn't turn very sharp, but it flew right through recognizable square loops and eights.

The later versions of the KF and KFm airfoils with the airfoiled leading edge flew better, but later research all showed that  the sharp corners only worked over narrow ranges and they ended up using forced control of the airflow over the wing, similar to some of the boundary layer control experiments.

A lot of work for very limited and targeted advantages.
phil Cartier

Offline Gerald Arana

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Re: Egad .
« Reply #2 on: November 27, 2018, 07:51:24 PM »
I used the K-Fm 3 on a hand launch glider several years ago. Hard to get much height as it was VERY draggy, but it did go OOS over the Watsonville airport.

I sent my survey aide (chain man) after it.......... what a mean trick! I knew it wasn't coming down any time soon! Hahahaha  He needed the exercise!

Jerry


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