Hi, Kim-
>Can you tell us anything more about your really cool flapless airfoil? I'm also curious what
>aerodynamic considerations led you to change the planview?
FWIW: I wanted a larger, slower plane than the "Whipsaw". Starting with the NACA 63A010 (as archived), I moved the point of maximum thickness up to 24% and 23% chord and thickened to ~19% and ~20% for root and tip, respectively. To get the t.e. thickness I needed, I had to create a longer chord at a lower percent max. thickness, so that I could chop it off at the t.e. to get these specs.
This was with Profili I. A couple weeks ago I finally registered and sent in my donation for Profili II (does spars and...?), but haven't played with it yet. Anyway, this scientific sounding method gave me an airfoil with an "eyeball-engineered" l.e. radius that looks good (never measured!): big enough, but not as blunt as an NACA 00XX section increased to those dimensions. It also eased the high-point transition (hoped this would alleviate problems at aft edge of l.e. sheeting) and stretched out the aft surfaces to a nearly straight taper.
One thing I noted while experimenting with this was that deriving a thicker section from this method did not seem to produce the same shape as using the NACA section generated by its own built in equation. For instance, a requested NACA 0019 did not look the same as an NACA 0010 fattened by 90%. Another thing I might note is that although the creator of Profili seems to have done a good job in a good cause, with sensible and generous expectations from users (i.e. a freeware Profili I, and a quite modest $10.00 USD donation to register for Profili II), David Lednicer posted a couple years back on the "Nurflugel" site that the archived airfoils in Profili seem to have come from the compilation he and Michael Selig display on the UIUC site.
Anyway, I used the same taper ratio as the "Whipsaw" (not the 'Super WS') to handle wind better than usual taper ratios at high A/R, but put the 1/4-chords in line spanwise for longer tail arm and to negate any dihedral effect from sweep. I then added a small fixed (stationary) flap, which brings area up to about 500 in^2 and lowers the A/R to about 6.1. Tips are modified, as was the horiz. stab/elevator. There are other more subtly "guestimated" features. There are a couple things I'm trying to enhance longitudinal stability. Tail Vol. coefficient is good, but I'm really guessing with the control quickness - stability trade off. That's the fun in it. However, even with a nicer fuselage profile, I think mine will lack the more harmonius appearance of the original "Whipsaw". The inside of the wing's pretty impressive though, and I seriously doubt that it will have root folding problems.
My desire at the time I drew this up was to make a very tight turning plane that was not a combat plane - for an LA .25. I wanted it light and knew that a relatively short-coupled model would lessen both weight and circular air flow effects against turns. My more recent "adventures" at the field hint that I perhaps should have drawn up a large flapped design first, but as Ty says, "I'm gettin' better." Perhaps I'll catch up with the plane by the time I fly it.
I never flew my over-powered, nose-heavy "Whipsaw", but believe that PDG may have created quite a little monster here, despite its thin wing section. It's numbers are impressive, and at its speed, it must have been pretty ferocious. I'd still be interested to hear what flyers discovered with it in the 1950's. I view my model as a descendent, but quite different plane.
Well, that's undoubtedly more than anyone wanted to know about an obscure experiment, but there you have it. As I said: FWIW.