Recent content by 3msinclair

I'm free to specify the prop myself. I did a bit of research and various model plane people suggest a prop diameter of ~ 25% of the whole wingspan and a pitch/diameter ratio greater than 0.6. Also, it seems to be important to keep the tip of the prop below the speed of sound as this drastically...

I'm afraid you've lost me a little bit again. The point of these calculations (for me, at least) is so that I can estimate what power my motor will have to supply to achieve a desired thrust, which should allow me to pick the right motor first time and not waste budget/time. As I don't really...

Thanks for the replies. So the consensus is that the second formula applies to the craft, not the air? I would assume that (neglecting efficiency/stray losses) the thrusts and powers should be equal, it would just be the velocities that differ. Is that right? And as a conclusion, for calculating...

I'm having some issues finding the relationship between power and thrust of a motor of a standard propeller based aeroplae. I've found two simple relationships that both make sense, but both (seem to) contradict each other. Thrust is equivelant to change in momentum: T = Mdot*v Power is...

I hope this isn't dragging up an old topic, but I'm currently looking for the governing equations for propellers and the relevant thrust/torque generated. I'm having a nightmare of a time trying to work out the relationship between RPM, pitch, diameter and generated torque/thrust. Could someone...