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(Solved): An airplane's Pitot tube used to indicate airspeed is partially plugged by an insect nest so that i ...
An airplane's Pitot tube used to indicate airspeed is partially plugged by an insect nest so that it measures of the stagnation pressure (gage), rather than the actual stagnation pressure. If the actual airspeed is , what is the incorrect value shown on speed indicator? a. b. c. d. e. The correct answer is:
Expert Answer
The airspeed indicator measures the difference between the dynamic pressure of the air flowing around the aircraft and the static pressure of the air in the atmosphere. The dynamic pressure is equal to the stagnation pressure minus the static pressure.Let P_s be the static pressure of the air, and P_stag be the actual stagnation pressure. According to the problem, the Pitot tube measures 46% of the actual stagnation pressure, so the pressure difference that the airspeed indicator measures is:P_dyn = P_stag - P_s = 0.46 P_stag - P_sAt the same time, the airspeed indicator measures the speed of the aircraft as a function of the dynamic pressure. Let V be the actual airspeed of the aircraft in km/h. Then the speed indicator shows:V_ind = k sqrt(P_dyn)where is a calibration constant that depends on the design of the airspeed indicator.