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From: "george lendich" <lendich@optusnet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-890535@logan.com>
Subject: Re: [FlyRotary] Re: Props
Date: Thu, 22 Dec 2005 07:39:46 +1000
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Buly,
Looking at the formula given by members on this list, 2 out of 3 were spot
on with Hoverhawk and the third was close.

Examples:
1. Prop Dia x 3.1416x RPM/ 720 - Correct!

2. Prop RPM x Dia x .00436 - Correct ( 3.14/ 720 =.00436)

3. 3.14 x 64 {given prop dia} ( 5500/2.17 {given RPM})= 508346/707 -
slightly incorrect ( as compared to the other 3 examples, which include
Hoverhawk)

i.e 3.14/ 707 = .004809 whereas all the others are 3.14/ 720 = .00436.

Now that I have that sorted - can someone tell me how to calculate pitch,
easily!!
George ( down under)


> Thanks Perry. This makes me feel much better. Looks like the formulas
> given to me were not good.
> Buly
> On Dec 19, 2005, at 2:00 PM, Perry Casson wrote:
>
> > I think your math is off a bit - Here's a online calculator http://
> > www.hoverhawk.com/propspd.html
> >
> > I think 6900 puts a 72" prop close to  mach 0.9 but I've never ran
> > mine above 6500
> >
> > Perry Casson
> >
> >
> >
> > --
> > Homepage:  http://www.flyrotary.com/
> > Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>
> Buly
> atlasyts@bellsouth.net
>
>
>
>
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>