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From: "DaveLeonard" <daveleonard@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: RE: [FlyRotary] Re: FW: Excel spreadsheet for calculations
Date: Sat, 18 Dec 2004 17:08:17 -0800
Message-ID: <PIEMJLCHGPKMFMDHBKMLGEHOCNAA.daveleonard@cox.net>
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Ok, it works like this.  Use the big spreadsheet.  There is a place for
ambient barometric pressure in inches Hg (you enter the blue numbers).  To
find the pressure at 10k you can use the spreadsheet I made.  Plug in 10000
and it will give the pressure in inches Hg, and PSI.

Then in my table plug in the 46"MAP you want and it will give abs PSI.
Subtract out the ambient pressure in PSI and that's how much boost you are
running - enter that in the manifold pressure area.  Then near the bottom
you find the temperature and pressure corrections, the corrected pressure
ratio and mass flow to be used on garrett charts.  The last big variable you
need is the RPM, as that affects your mass flow.  As I remember, you were
overpicthed, so say 5500 RPM.

Running those numbers for you give a P/R of 2.5 and a corrected mass flow of
30 lb/hr.


>
> Looks interesting, Dave, but I'm not sure what to plug in where.
> For example, If I wanted to know where I was on the attached map at say
> 10,000 feet and 46 MAP, how would I go about finding out, and what other
> information would I need?
> Regards
> John
>