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Old May 06, 2002, 06:46 PM
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Santa Barbara, California, United States
Joined Mar 2002
97 Posts
Sneu and Tzagi,
At initial launch, when the propellor parameter V/nD =0, the first motion is related to static thrust and the kick to start accelerating. As the plane gains velocity, the blades, if high pitched, start to lessen angle of attack, are no longer stalled, speed up , and the thrust changes. So static is only one point on the curve-but it is a point. I use a high speed blower to simulate "V" up to 30 mph but only on props less than ten inches. For the test stand pictured, we mount it on a pickup and calibrate at speeds to 40 mph. Not as good as a wind tunnel but better than guessing the coefficient of thrust (Ct) for the particuliar blade shape, aspect ratio, pitch, and tip shape. As per the request for better graphic, I'll send E-mail.
...Dick
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