Mailing List flyrotary@lancaironline.net Message #37565
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: PP Ve??? was Re: Intake CFM air flow
Date: Fri, 1 Jun 2007 17:19:31 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Ok, looks like all the bugs are out of the math and it looks like our PP 12A gets around 120%Ve.  That corresponds to a number I had hear before, but nice to have an example to support it.

Thanks Lynn, Blake and Bob

Ed
----- Original Message ----- From: "Blake Lewis" <blake.lewis@gmail.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, June 01, 2007 4:53 PM
Subject: [FlyRotary] Re: PP Ve??? was Re: Intake CFM air flow


Bob,
You corrected the wrong way. And I had 10000 instead of 10700 rpm.

12A  Pports can do 310 HP at 10,700 RPM at .667

If the .667 is BSFC then start with that

Density of air at sea level 15C = .0765 lbs/cf air/fuel = 12

.667 bsfc x 310hp is 206.77 lbs/hr fuel

206.77lbs x 12 = 2481.24 lbs/hr air

2481.24 lbs/hr  /  60min/hr = 41.354 lbs/min

(41.354 lbs/min)  / (.0765 lbs/cf) * (1728 ci/cf) = 93411 ci /min

(934113ci/min) / (10700 rev/min) = 87.30 ci/rev

1200cc / (2.54cm * 2.54cm * 2.54cm)/ci = 73.22 ci volume

87.30 ci/rev / 73.22 ci/rev = 1.192 =119% VE

Blake

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