First, let me say I am not a engineering student but just a average person trying to get his pilots license and enjoy working with aerospace problems.(adsbygoogle = window.adsbygoogle || []).push({});

My problem is:

“An aircraft is flying at 150 mph. The atomspheric pressure is 14.1 lbs./sq in and the temperature is 50 degrees F. Find the total or stagnation pressure at the point on the airfoil. If the pressure at a point on the upper surface of the airfoil is measured and found to be 13.9 lbs/sq in., what is the local air speed at this point?”

I am trying to use the Bernoulli principle to solve this problem

P1 + ½ρV^2 = P2 + ½ρV^2

I have converted a few things to help work with the equation:

150 mph x 1.4667 = 220 ft/sec

50 F + 459.6 = 509.6 degrees Rankine.

14.1 x 144 = 2030 lbs/sq. ft.

I understand that as the velocity increases the pressure decreases in the venturi tube and that as velocity decreases the pressure will increase but I am still having trouble solving the entire equation and I guess understanding how to calculate everything in the problem.

Here is what I have though and please correct me if I am wrong or have mathematical errors or failed reasoning 101.

Solving for P1 (dynamic pressure)

2030 + ½ (.0023769 slugs)(220)^2

=2030 + (.00118845)(48400)

=2030 +57.52

=2087 lbs/sq ft.

How do I go about solving the the second part of the word problem if the pressure is measured at 13.9 lbs/sq in., what is the local air speed? Do I just plug in 2001 lbs/sq. ft (13.9 x 144) for P2 and solve for V^2?

Also, let me apologize for the ole school units. My book came from a old bookstore and it by a professor at University of Kansas (Vincent Muirhead). I would like to have the Intro to Flight by Anderson but I refuse to give 180.00 for a book.

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# Aerospace Stagnation Pressure on Airfoil

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