No Hanaka, I was not saying that the OP did not say that propellor thrust did not vary with speed - it was his/her use of a measured static thrust of 508 lbf in the following:
- max_Thrust_propellers = 508 pounds
- Speed_plane = 70 miles/hour
- Power_engine = 40 HP
Yes the arithmetic is fine (don't bother with all those irrelevant SI units)
(508 * 70 *(88/60))/550 = hp
but the 508 lbf assumption is wrong.
As I wrote before, I was not going to get involved in this thread which advances a theory, based on a single unverifiable assumption, as truth.