An airfoil is moving through the air at 540 mph at 15,000-ft pressure altitude. The temper- ature is 45°F. At a point on the airfoil upper surface, the local velocity is 630 mph. What is the pressure at that point? If this is the average pressure on the surface, how much lift per square foot is being provided by the top surface? If the average speed on the lower surface is 495 mph, what is the pressure and average lift per square foot on the lower surface?What is the total lift per square foot of wing area?
(a) Solve using incompressible equations.
(b) Solve using compressible equations,
(c) What are the percentage differences in the lift value determined by parts (a) and (b)?
(d) Find the local Mach number on the upper surface of the wing.