Mailing List flyrotary@lancaironline.net Message #39939
From: Ron Springer <ron2369@sbcglobal.net>
Subject: Re: [FlyRotary] Math Help
Date: Thu, 18 Oct 2007 12:07:50 -0700 (PDT)
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Steve,

For a flat plate 90 deg to the flow, the drag
coefficient is about 1.17. The drag is equal to the
drag coeff. times the plate area time the dynamic
pressure. For a fixed true airspeed of 200 mph, the
dynamic pressure varies with altitude. It is 0.71 psi
at sea level and 0.52 psi at 10,000 ft.

So, the drag force is 12.5 lbs at sea level and 9.2
lbs at 10,000 ft. Hope that helps.

Ron


--- Steve Thomas <steve@stevet.net> wrote:

Not being much of a math or engineering whiz, can
anyone help me  calculate the force the relative wind would put on a
device that  hangs in the breeze on my airplane?  Assuming a 200
MPH airspeed, and  a flat plate of 15 sq. inches, what would be the
amount of force on  the plate in pounds?

Best Regards,

Steve

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