Gental Lady Foil?

[blacksheep]

Is there any one out there that can tell me what foil Number the Gental Lady uses? I am designing a sail plane and wish to use the same foil.
If some one has a rib to scan that would do also.
Thanks,
Black sheep.

[SoCalGliderFlyr]

I think it's a N-11.5R.

That is Nike sneeker size 11 1/5 Right shoe. Most likely the outter edge around the small toe.

[Sparky Paul]

Here's the Electra.. same outline..

[blacksheep]

Thanks guys I think I have what I need now.....
Ill give a sneek peek after the design is completed and tested.
Blacksheep :D

[SoCalGliderFlyr]

I think the Electra is a C10L. That is a Converse's size 10 left foot.

You guys think I'm kidding. You didn't have the pleasure of listening to all of the original kit designers/builders gabbing about. Wasn't till Eppler and Selig that anyone paid much attention to miniture airfoils. Many of these flat bottom airfoils were pure conjecture. One designer did use the side of his shoe as he couldn't find his french curve at the moment.

[Peytr]

I scanned the GL foil a while ago and smoothed it in Profili (the Xfoil utility) and did a comparison with existing foils. I found it practically resembles the Neelmeijer foil. In fact the difference might be scanner and smoothing distortion.

[SoCalGliderFlyr]

That's nice. Bet Carl Goldberg had no idea of what the Neelmeyer airfoil looked like in the late 60's when he started using his home spun airfoil.

[TLyttle]

I'm not convinced about the lack of airfoils over the years; there are too many models out there with very specific airfoils, going back to the 30s with Ritz, RAF, etc. Whether these models flew any better with other airfoils or not, I have no idea.

As far as GL airfoil is concerned, whatever it is, it works fine in its own speed envelope. My propensity for D-tubing open structures like that completely changes what is, at best, a random airfoil. I do like to move the highpoint back if I can, and apply a bit of undercamber in the last 10% or so, kind of a BS 193 if you like. I DO know that I get to do anything I like with my GL without fear; it always hangs well in thermals, lands at a respectable speed, and certainily is much stronger with the D-tube.

This, of course, does NOT mean that I haven't used the BB 9.5 (British Brogue 9 1/2) for some of my models...

[BMatthews]

The Lady's airfoil is the same one Carl used on a number of his 50's and early 60's vintage FF gas models. The Hi Thrust Viking uses the same airfoil. He designed it himself. Wether it was from a nice ready to hand shoe or some other guiding knowledge is hard to say. But he sure didn't have access to wind tunnel data or Neelmyer airfoils. But he was not alone in using thin flat bottomed shapes. There were a number of designs of that time that used the same general shape of airfoil designed by many a different name. Someone got brave, found that it worked well and everyone jumped on the bandwagon. This one example may have been designed by Carl but he sure was not the father of this general trend in airfoil shaping.

[Sparky Paul]

I flew a lot with Frank Ehling back east.
He used "zip-zip" airfoils for the most part, but based on his previous experiences.
He was a superb designer-flier.
And he used french curves, not shoe soles for the shapes.

[TLyttle]

Yeah, but Frank was not only a professional, but a true expert...

My buddy built a MB Dragonfly (his 4th!), and in a fit of insanity, decided on a Wortmann-style airfoil into the wing (~25-30% thick). It is very difficult to see much difference between it and the airfoil called for. But what a wing!!!

[BrianSmith]

I traced all the GL kit ribs out on paper some years ago..I saw it in my note book the other day..Yours for an address if interested..Brian Smith

Is there any one out there that can tell me what foil Number the Gental Lady uses? I am designing a sail plane and wish to use the same foil.
If some one has a rib to scan that would do also.
Thanks,
Black sheep.

[blacksheep]

Brian,
Yes please please send me them. Can you scan them and email them? or do you wish to mail them to me.
Thanks once more.
Paul, AKA Blacksheep. :D