Cirrus SR20 cruises at 155 kts at 8000 ft geometric altitude. Its wing has span, b = 38.333 ft, Sref = 144.9 ft2 & has a mean aerodynamic chord (MAC) = 4.04 ft.You will test a 1/4 scale model in the Texas A & M wind tunnel, assuming sea level conditions
a) Calculate the full scale Mach & Reynolds number based on the MAC. Calculate the model scale Reynolds number using the model scale MAC.
b) Calculate the ratio of full scale-to-model scale Reynolds numbers & discuss how you could achieve the Mach number & full scale Reynolds number on the 1/4 scale model in the TAMU wind tunnel.
Also, Let the SR20 be operating at steady level flight at the conditions identified for FULL SCALE and at L/D ratio of 20. The weight is 3050 lb.
• Calculate CL & CD of the aircraft.
• Calculate the wing loading, W/S.
• How much thrust is the propulsion system generating?