snip
BTW as an exercise for the reader how much HP does it take to
climb a 1800 pound gross weight  RV4 at 1500 feet per minute not
counting the HP required to over come drag. Show your calculations.

Paul Lamar

Power is force * velocity / 33,000.
1800 lbf * 1500 fpm / 33000 = 81.8 hp Imp.
in metric:
1800 lbf = 8006.8 N, 1500 fpm = 7.62 m/s, 1 metric hp = 735 Nm/s,
power = 8006.8 N * 7.62 m/s / 735 = 83 hp metric;   divide by 1.015 =
81.8 hp. Imp.
Do I pass?

As a genuine question: How much would drag add to hp needed,
approximately? for the RV4? or per cross-section area of the plane. Do
you have rough numbers without going into speed, drag coefficient of the
plane shape, mass of air which changes with temperature and altitude,
etc. Maybe for rough calculations one must consider speed, however.

Regards
Rolf Pfeiffer

"Do I pass?"

I don't know. I would have to convert everything to the French system
of measure (AKA metric system) and I am not sure I want to do that. As
Vance is fond of saying; "we got to the moon on inches." What have the

French

ever achieved?

Flat plate area is about 2 to 3 square feet but at or below best climb
speed induced drag (drag due to lift) is a large factor.

Paul Lamar

Here is what my BASIC model says about an RV6 - well made, but not Tracy
Saylor
slick - with a fixed pitch prop on an 0-320 160hp - sea level std day. an
RV4 would
be slightly lighter and very slightly less drag - and an RV8 a bit more
Vance J

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