Hi there,
this is an interesting conversation for a change, but I note that the original question has gone completely unanswered:
How to determine the best endurance speed using an experimental method?
(my emphasis)
Ok, so we all know that best endurance speed is Vmd (minimum drag) and this has already been pointed out.
So now the question can be rephrased as: "
How does one find Vmd, experimentally, for a particular airframe?" I believe that question had been answered some time ago over at Tech Log or Flight Testing. Those are undoubtedly the best places to ask.
Lastly, I note that the question only asked about the value for best endurance speed so, for all its practical interest, by and large the power settings (mixture and prop pitch) are not relevant as far as this question goes. Best endurance will always be obtained at the same EAS. The
amount of endurance you will get out of the aircraft will of course vary significantly depending on the power settings being used but that is not a consideration here, do we agree?