On Tue, 24 Apr 2001, Paul wrote:

I have a 1500 pound airplane climbing out at 2000 FPM at 100 MPH.
The equivalent flat plate area is 2 square feet. What thrust is
the prop generating?

Paul Lamar

Byron Ward wrote:

2000 ft/min * 1 min/60 sec * 88 ft/sec/60 mph = 22.7 mi/hr

tan^-1 (22.7 mph/100 mph) = 12.8 deg (flight path angle)

1500 lb sin (12.8) = 332.3 lbs (weight acting opposite to velocity)

.5*.002377 slugs/ft^3*(147 ft/sec)^2*2 ft^2 = 51.4 lbs (drag)

=> thrust = 332.3 lbs + 51.4 lbs = 384 lbs

But since you said thrust of prop, not aircraft, I guess the angle of
attack and angle of the thrust line would change this a little (since
thrust of acft is by definition opposite the velocity, thrust of the prop
isn't necessarily).

Byron

Right answer Byron but the long way around. Hint: how much HP does it take
to lift 1500 pounds at 2000 FPM?

Paul Lamar
 
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