John,
The Excel equation for finding the blade angle for a given pitch setting in
inches is as follows:
ANGLE = DEGREES(ATAN("pitch in inches"/(PI()*"diameter")))
"pitch in inches" is the desired pitch in inches.
"diameter" is 2 times the radius at which the angle is measured. Warp Drive
says to measure the blade angle with the protractor mounted at the tip.
However, the Warp Drive protractor actually measures a little back from the
tip (when mounted flush with the blade tip), not exactly at the tip. Based
on Larry's information, when you mount the protractor at the tip, you are
measuring at 1/2" back from the tip, thus the need to use 53" rather than
54" for "diameter". (This makes sense if the Warp protractor is 1 inch
wide, angle measurement 1/2" from the tip.)
Based on this diameter adjustment (for the width of the protractor), which I
had not previously accounted for, my pitch is 63.5" rather than 64.5" with a
diameter of 58". Obviously, my pitch had to be set higher than Larry's and
yours because I have a slower engine (rated at 2300 rpm).
I agree with Larry in that the diameter of the prop has no effect on pitch
(in inches), but the diameter/radius where you are measuring your pitch
angle does affect the pitch (in inches) calculation.
Ken Jones
N5834
----- Original Message -----
From: "Martindale Family" <johnj...@chc.net.au>
To: "KRnet" <kr...@mylist.net>
Sent: Friday, August 20, 2004 6:00 AM
Subject: Re: KR> Blade angles Warpdrive
> Larry
>
> Your prop is identical to mine at 3 blades and 54 inches. I'll try to
email
> you and Ken the WarpDrive
> chart in Excel that someone on the list supplied for a 2 blader. Thanks to
> that person whose name now eludes me...sorry.
>
> John
>
> The Martindale Family
> 29 Jane Circuit
> TOORMINA NSW 2452
> AUSTRALIA
>
> phone: 61 2 66584767
> email: johnj...@chc.net.au
> ----- Original Message -----
> From: "larry severson" <lar...@socal.rr.com>
> To: "KRnet" <kr...@mylist.net>
> Sent: Friday, August 20, 2004 10:06 AM
> Subject: Re: KR> Blade angles Warpdrive
>
>
> > Pitch is not related to diameter, but it is on a 54 in 3 blade prop on a
> > Revmaster 2100D turbo.
> >
> > At 07:16 PM 8/19/2004 -0400, you wrote:
> > >Larry,
> > >
> > >Is that based on a 53" diameter prop?
> > > >
> > > > I called Warp Drive. They gave me the figure of 18 degrees to get 54
> > >pitch.
