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Date: Fri, 01 Jun 2007 08:16:10 -0400
From: Bill Bradburry <bbradburry@allvantage.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Intake CFM air flow
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Thanks Bob and Ed.

I would appreciate the pictures, Bob.

Ed, I expected a much higher flow.  I thought that it would be in the 
neighborhood of 600-800 CFM!  I guess I have been spending too much time 
  reading the carburetor adds for V8s....
I think that the 278 CFM would translate to an air velocity of about 
48.25 MPH going through my 3 inch throttle body.  That seems like a 
gentle breeze!  Maybe I am spending too much time trying to remove 
restrictions to the air flow in the inlet??  :<)

Bill B


Subject:
Re: [FlyRotary] Intake CFM air flow
From:
Bob White <rlwhite@comcast.net>
Date:
Thu, 31 May 2007 18:48:02 -0600

Hi Bill,

I built a can around it out of aluminum.  The can clamped on at the
same place as the filter and it was about 6" dia or maybe a little
larger.  I then made a fiberglass air inlet that sealed to the can with
a strip of red silicon engine baffle.  I was hoping to generate some
ram air pressure, but didn't get a chance to measure it to see how good
it worked.  I'll take some pictures next time I get to the airport.

Bob W.


> Subject:
> Re: [FlyRotary] Intake CFM air flow
> From:
> "Ed Anderson" <eanderson@carolina.rr.com>
> Date:
> Thu, 31 May 2007 19:22:24 -0400
> 
> 
> Bill, at 6000 rpm the airflow is 277 CFM assuming 100% Ve.  Here is a 
> formula
> for calculating airflow for the rotary.
> 
> Air Flow (CFM) = (40 cubic inches per face)*2(number rotors) * 3(faces 
> per rotor)*rpm of rotors(=  E shaft rpm/3) /1728 (conversion to CF) = 
> 40*2*3 *(6000/3)/1728 = 240*2000/1728 = 277.77 CFM
> 
> Or simplifying Air Flow (CFM) = 80*RPM/1728 = 277.77 CFM air flow at 
> 6000 rpm for a 2 rotor.
> 
> Ed