"xerj" wrote in message
...
I understand the theory vis a vis lowest L/D TAS and the power
available/power required chart, but let's say you're in flight in a
normally aspirated prop plane, your destination is blown up, your
alternate is unservicable for some reason or other and you need to
stretch the fuel you have the farthest distance possible.

What are the quick and dirty steps to working out the optimum alt and
speed? I mean in the cockpit, not in the comfort of home.

Thanks in advance.



Unfortunately, there's no quick & dirty way. The usual (Bruguet) theory
is deficient in its assumptions, and the usual cruise table is deficient
in that the wrong independent variables were selected by the GAMA
committee. At those lower speeds, you can't depend on propeller
efficiency being independent of air speed. For details and an example of
what to do, see the cruise chapter of Performance of Light Aircraft.

John Lowry
Flight Physics