Mailing List flyrotary@lancaironline.net Message #37629
From: Bob White <rlwhite@comcast.net>
Subject: Re: [FlyRotary] Intake CFM air flow
Date: Sun, 3 Jun 2007 09:52:57 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Bill,

Here is one shot of the air intake.  There are some more at
http://www.bob-white.com/album/main.php?g2_itemId=532

There is one piece missing from the photos.  I didn't connect the air
filter directly to the throttle body.  There was an alternate air
source that added several inches to the length.  The last photo is a
picture of the box the alternate air device came in with the P/N.  It
was broken, and I threw it away.  I attached a picture of a similar unit
that I found on ebay (item 160048910751).  I never tested this to see
how effective it would work.

Bob W.

On Fri, 01 Jun 2007 08:16:10 -0400
Bill Bradburry <bbradburry@allvantage.com> wrote:

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

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