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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-369618@logan.com>
Subject: Re: [FlyRotary] Re: Compressor maps
Date: Wed, 18 Aug 2004 12:00:29 -0400
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Mike makes a good point.  While the official displacement of the 13B is
1.308 liters (actually 1308 cc), for airflow/power purposes it acts the same
as a 4 cylinder engine of 40 CID (each cylinder) or 160 CID or 2.6 Liters.

CFM = (4*40)RPM/(1728*2) so for 6000 rpm, CFM = 160*6000/(1728*2) = 277.77
CFM at 100 Ve

Some compressor maps use CFM on the X axis and some use mass flow usually
Lbs/min.  My spreadsheet automatically calculates the lbs/min of air flow
for every rpm and power situation.  Or its easy enough to calculate.

Just multiply your air flow volume in CFM by 0.076 for sea level density.
So in this case 277.77*0.76 = 21.1052 lbm/min


Ed
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message ----- 
From: "Mike Robert" <pmrobert@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, August 18, 2004 11:14 AM
Subject: [FlyRotary] Re: Compressor maps


> John Slade wrote:
>
> > John, here is a URL to a pretty good discussion on reading compressor
> > maps with examples
> >  http://cybrina.mine.nu/MR2_Docs/compressor_flow_maps.htm
> >
> > That's great, Ed. And you did it in one sentence. :)
> > Do you happen to know the engine capacity (in litres) and the
> > volumetric efficiency of an REW engine?
> > Regards,
> > John
> >
>
> John, the auto people use 2.6 litres and .55 for those turbo map calcs.
>
> HTH, Mike
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>