> Just wondering, if I was to make them based on the upper half of the
> wing profile, would that be a reasonable suggestion or does Reynolds
> Number apply here and stuff if all up ? . . . . Not that I understand
> Reynolds Number mind you, but I do know there is such an animal.
>
> Cheers
> Kingsley
Hoerner doesn't suggest laminar flow techniques as relevant for small
airfoil sections, like struts, or gear leg or similar small fairings.
Classic airfoil shape OK. Not that I understand it all either, but he
does document an effect called "critical Reynolds number" on the these
small airfoils, where beyond a certain R'number (derived from velocity
and chord length), drag increases dramatically. Like around 10 to the
4th power, where our wings I think are like around 10 to the seventh.
One of our EAA Chapter members is an actual NASA scientist working out
at nearby NASA-Glenn Research (now working temporarily in the UK, BTW).
He talked to our meeting once about one of his projects, namely
super-low Reynolds number flying machines. R'numbers in the hundreds, I
think he said. Well, I guess if NASA-Glenn has a really noisy Mach 6
tunnel, they can do really super-subsonic too. Actually I got two
detailed tours of that awesome place, on gov't salary on other gov't
agency business. Not your usual public tour, and adjacent to the big
Cleveland airport, I just like, flew there to commute to work. Ask for
the right FBO off famous Taxiway R and you can quickly walk to NASA.
Embarrassing even to accept compensation via taxpayer dollars.
Why his research? Well, the proposal was an unmanned airplane on Planet
Mars. What was fascinating is how he related aerodynamic lift/drag
effects up there in their gravity and atmosphere, and the type of winged
vehicle needed in subcritical R'numbers. Almost like if there ever were
a Martian civilization, they would have discovered flight very early on.
Little "grey guys" with big heads and almond-shaped eyes, flitting about
using "flatulence" for propulsion -- the off-the-chart numbers he gave
us!
Fred F.
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