It is a handy feature to have washout at the tip and higher pitch at
hub this prevents prop tip stall and slows the prop at hub due to
usually large area there under high toeque conditions. Note that this
is not the same as just using a say 24 pitch block and setting to 30"
pitch on pitch gauge My current f1d props use this type of design and
it gives a noticable improvment they are vp's with 27 low pitch
giving 32 pitch at root and 24 at tip the washout is last 2.5 inches
of prop dia and washin at hub is last 2 inches of blade
vlad
--- In Indoor_Construction_at_yahoogroups.com, "Mark" <f1diddler@...>
wrote:
>
> --- In Indoor_Construction_at_yahoogroups.com, LeRoy C Cordes
> <lcordes_at_> wrote:
>
> << A MiniStick
> > plan I have calls for an 11" pitch, would that be the 11 on the
> Bradley
> > gauge ?
> >
>
> Technically, YES, but with some practical caveats. A given angle
at
> a certain pitch will occur at the same radius on a prop regardless
of
> the overall prop diameter. But for "pitch setting purposes" this
> assumes the blade is formed at close to helical pitch (rate of
> twist.) If that's not certain, then it's best to pick a
compromise
> radius at which to set pitch, and that becomes the "nominal
pitch."
> 70% of radius seems a good compromise for ministick. If you want a
> 11" pitch, set blade at 34 degrees at 2 5/8" radius. This should
> yield 11.1" pitch. Now, how this comports with a "Bradley pitch
> gauge" I can't say. If gauge was designed for larger props, it's
> possible that the wiggle at the shaft holder could wreck an
accurate
> pitch setting for a ministick prop. You just have to watch how
much
> things move around on the gauge, at all times. If your gauge works
> off of 45 degree angle, as some do, then set 45* at 1.75". Should
> yield 11.0" pitch also.
> Mark F1diddler
>
Received on Mon Feb 18 2008 - 06:05:31 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:45 CET