"Byrd, Ray" wrote:

Yes, as before, large-section, well-shaped bodies (max thickness well aft),
can have less drag than smaller "knobby" shapes. But other factors are also
important, e.g., I recently read a very good article on airfoil selection by
Bill Husa. The "blimpiness" of the Questair is not a singular key to its
speed.

http://www.oriontechnologies.net/Documents/Airfoil.htm

He writes that Glasair spent some serious effort to understand why the
Questaire Venture could "easily outdistance the Glasair on substantialy less
horsepower". He concludes that selection of a low-pitching-moment airfoil
(and wing aspect ratio, no doubt) led the Questair to a lift/drag of 33.55,
whereas the Glasair L/D was only 16.56.

The very low-pitching-moment airfoil leads to reduced trim lift (and drag),
enabling the short fuselage and an apparent "blimpiness".

Both planes have fuselages subject to the very turbulent and rotational air
flow behind a propeller.

Think "reduced fuselage wetted area". This, and overall small size/light
weight, is key to the usual relative high speed of extreme designs such as
Rutan's EZs, Lancairs etc.

Ray Byrd

Right facts, wrong conclusion.  The wing mostly controls the
drag of light aircraft, other factors are significant, but secondary.
Fast wing, fast airplane, slow wing, slow airplane.  Not absolute, but the
general principal.

Bill Freeman

I don't know where you are getting your numbers Bill but:

What do you mean by "mostly". We need some "real" numbers here. The numbers 
I have for these old airplanes is fuselage 25%, wings 35% tail 10%
landing gear 15% and the rest is engine and engine cooling.
That does not exactly make the wings "mostly".

This is from Your wings Assen Jordanoff.

Paul Lamar
 
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