Originally Posted by TU114
Also, why not turn the pitot tube around? Then, Ptot will no longer be Pstat+Pdyn but Pstat-Pdyn
I wonder what an aerodynamicist would have to say about that assumption.
AFAIK sailplanes use a venturi to produce a pressure of Pstat - Pdyn to drive a total-energy variometer.
Originally Posted by henry crun
Did nobody reconise it is a stand-alone direct-reading machmeter? No other air data required!
A machmeter indeed, measuring the local Mach close to the airplane. But staying airborne has to do with pressures, so you still need ambient pressure (Pstat) to have something that relates to lift.