--- In Indoor_Construction_at_yahoogroups.com, "markdrela" <drela@...>
wrote:
>Let's
> do the level cruise case first, since there we have a better idea of
> the CL.
> S = 0.11 m^2
> W = 0.018 N
> CL = 0.6 (wing should give about 0.5, stab about 0.1)
> CD = 0.12 (L/D = 5)
>
> These specs imply
> V = 0.67 m/s
> D = 0.0036 N = Thrust
>
> I think this will give much smaller chords, and a torque closely
> corresponding to the cruise torque.
That definitely produces a better looking prop. Thank you :)
Using Velocity=.6m/s, Torque=.001Nm (.15 in/oz – F1D cruise torque),
and Diameter=.5m, Javaprop gives a design that looks a whole lot like
what we are using currently. 1.8 pitch/diameter, 64mm cord,
elliptical-ish planform. Neat!
Is the next step to try to increase efficiency by trying different
parameters (diameter, rpm, etc)?
p.s. Should S include any stab area, since the stab is contributing
lift? If so, would that reduce V a little? Using a Velocity
of .67m/s produces a cord a bit smaller than what seems to work best
in practice, but if I reduce the velocity a little it gets closer.
Or perhaps the wider cord is due to off-design performance at higher
pitch (for Variable Pitch props).
Received on Thu Aug 24 2006 - 13:16:15 CEST
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:44 CET