- Oct 18, 2003
- Saline Michigan
Drag (and thrust required) goes with indicated airspeed squared, so you just computed the thrust ratio increase needed to make that speed increase. Power is force times speed, and so power IS a speed cubed function. Power would have to go up by about 2.4 times to get that bird from 140 to 187 knots indicated.Sorry but drag increases with the square of speed not the cube.
The correct 'rule of thumb' is Power2=Power1*(Vel2/Vel1)^2
ie 140 to 187 knots ==> 1.78 times power
I do not think any of us buys the theory that Raptor is cruising 140 knots indicated on only 125 hp, and that is what it would have to be to make numbers on 300 hp.