Mailing List flyrotary@lancaironline.net Message #7452
From: Chad Robinson <crobinson@rfgonline.com>
Subject: Re: [FlyRotary] Re: Performance Props
Date: Wed, 21 Apr 2004 21:11:20 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Perry, if you could share the formulae you're using I'd be happy to make a spreadsheet calculator for this. So far I've found very complex prop calculators but nothing straightforward.

By the way, why are you asking desired cruise speed? 400 knots! =)

Do your calculations focus on pitch/length or do they also provide some means of calculating dimensions at various stations from the hub, so forming templates can be made?

Regards,
Chad

Perry Mick wrote:
On Wed, 21 Apr 2004 20:19:12 -0400, Bulent Aliev wrote

On 4/21/04 12:44 AM, "Perry Mick" <pjmick@mail.viclink.com> wrote:


Bulent:
Are you looking for a wood prop or composite? Al's method is wood, mine

is

composite. I think with your HP you would need a prop similar to what

I've

built for Cosman, but it still needs to be tested.


Hi Perry, I want to build one like Al Wick and Phil Johnson did. Wood / composite prop. This way I van get some initial performance numbers for the final prop. I would like to have one like Cosmanšs,
but I can wait to be tested. In the mean time Išll have something to start with. Bulent


Tell me:
your engine HP at X RPM sealevel
redrive ratio
cruise RPM, and desired cruise speed at that RPM
number of blades, 2 or 3 (probably 3)
prop diameter (limited by rotation angle on a pusher)

I can work up some numbers for you to build to, blade pitch and chord.

Perry




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