Mailing List flyrotary@lancaironline.net Message #5632
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: air flow
Date: Sat, 31 Jan 2004 13:54:09 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
 
 
 -----
From: Al Gietzen
Sent: Saturday, January 31, 2004 11:50 AM
Subject: [FlyRotary] Re: air flow

 

 Here is a formula   80 CID * RPM/1728.  Example for 6000 rpm,  80*6000

rpm/1728 = 277.77 Cubic Feet of air per minute.  A cubic foot of air (at sea

level standard day) is approx 0.076 lbm/cubic foot   so 277.77*0.076 = 21.11

lbm/min air mass at 6000 rpm .  Just change the rpm to what ever value you

want.  Also note the weight of air of course decreases with altitude so

277.77 CFM provides 21.11 lbm/minute at sea level but less at altitude.

 

Note this assumes 100 % Volumetric efficiency.

 

Ed Anderson

 

Oh; boy, now you’ve done it.  My beautiful intake scoop is already installed, and I apparently designed it based on the wrong number.

 

You’re numbers look right to me.  I’ll have see if I can figure out what I did.

 

Thanks.

 

Al

 

Your Welcome, Al

 

    Perhaps you used the correct number for the design and just had a brain fade when you quoted the number for CFM - Hopefully?

 

Ed Anderson

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