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From: "George Lendich" <lendich@aanet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-4183343@logan.com>
Subject: Re: [FlyRotary] Re: P-Port performance
Date: Tue, 30 Mar 2010 17:52:23 +1000
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Blake,
That 1.87" is 47.5mm and he doesn't wish to accept, less is more. I think he 
would use 2" ID if he could get it easily.

 It's the same thing with carbies all the literature says don't go too big - 
all for the same reason. I got a feeling 44mm is bang on the money or maybe 
a little too big as not many will be going to 7,500 rpm on take-off. At 
7,200 only 42.44 is needed, that's 5mm difference. Powersport were getting 
210hp on 40mm at 6,000 rpm. My calculations ( using Ed's methodology) says 
39.42mm at 6,000 rpm. The calculations seem to be striking the right chord 
to me.

I calculated to 7,500 rpm as I'm planning a single rotor and might need a 
little more for the extra HP.

I believe Bill is designing for 1.75" or 44.45mm and will be testing this 
down the track.
George (down under)

> Just to get it right, Paul Lamar is building p-ports with 2" OD
> tubing. The stainless tubing is  1.87" ID. The Lemans motor drawings
> he lifted dimensions from is 2.0" ID at the port and 2.1" ID runners.
>
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