I think having a high frequency sound transmitter in the nose of the aircraft and receivers in the wingtips and tail would work. Measure the frequency shift and you have the airspeed. Like a train whistle going past you..doppler effect. In effect, youre sending something (sound) into the medium youre flying through (air) and you're measuring its progress. Distance and absolute speed are known, time is calculated, airspeed can be derived?
Last edited by AfricanSkies; 20th Jan 2015 at 18:51.