The air flow is restricted by the small distance between the motor and the blades. My intuition is that this restriction in mass flow would translate into a restriction in air velocity output hence be the equivalent of lowering the RPM proportionate the the lowering of mass flow. I base this on my surmise that the non-linear increase in power with RPM is due to the v^2 term of kinetic energy,
On Fri, Apr 12, 2013 at 4:03 PM, Alan Fletcher <a...@well.com> wrote: > Oops : 16 x 10 (not 10 x 16) > > Thrust calculator > http://members.jcom.home.ne.jp/4223215501/staticthrust.htm > Plugging diameter 16" pitch 10" 2500 rpm and 100% efficiency gives > 55W = 0.07HP > > I'm nor sure what the efficiency is for converting electrical input to > motor shaft output. 80-90% ? > > It does go up very rapidly with RPM > > 2000 : 25W > 2500 : 50W > 3000 : 85W > 3500 : 135W > 4000 : 202W > >
