Just a little heads up for those who like to get into the details of different props and engine power numbers etc.

I've had a closer look at the data from APC themselves (https://www.apcprop.com/v/PERFILES_W...tDatafiles.asp) and there is something strange with the 7x4 prop. Don't know about the other props (there could be similar errors) but here is a plot that illustrates the problem. The red curve is from their data base and it doesn't follow an rpm^3 curve after about 17000rpm.



So these numbers seem more accurate (power in HP = P x rpm^3), and replicate the APC data file for revs below 17000rpm (also shown in the blue curve above);