On Mon, 29 Aug 2011 15:18:41 -0500, Bart wrote:



It does, indeed. But to be Hobbs equivalent it would have to be
"total" or "cumulative" time of flight.

Bart

True. Getting back to Paul's original question, how about using a pitot
tube to a pressure switch. There are pressure switches made for HVAC
ducts that are rated for pretty low pressure (quick search on Grainger
revealed some that actuate with as little as 0.02 in WC pressure). Quick
pitot calculation reveals that 20 MPH = 50 Pascals pitot pressure, or
about 0.2 " WC, so such a switch should work.
--
Stefan Murry