Return-Path: Received: from relay04.roc.ny.frontiernet.net ([66.133.131.37] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2881234 for flyrotary@lancaironline.net; Mon, 08 Dec 2003 00:56:07 -0500 Received: (qmail 20873 invoked from network); 8 Dec 2003 05:56:06 -0000 Received: from unknown (HELO frontiernet.net) ([170.215.97.8]) (envelope-sender ) by relay04.roc.ny.frontiernet.net (FrontierMTA 2.3.6) with SMTP for ; 8 Dec 2003 05:56:06 -0000 Message-ID: <3FD412CF.D465912E@frontiernet.net> Date: Sun, 07 Dec 2003 23:57:35 -0600 From: Jim Sower X-Mailer: Mozilla 4.77 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: K&M and Thick Radiators References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit <... How do the Mass Air requirements change with altitude ...> They don't, except as the heat rejection requirements change. You get the same mass airflow at 180 kias at sea level or 15 k ft. Of course your TRUE airspeed at 15k is a lot higher and that's what pumps more of the thinner air through the system. Also, to the extent that fuel flow is less at 15 k ft, so you have less heat rejection requirements and therefore less mass flow requirements. <... if the fuel burn was 8.5gph and altitude was 25K ...> .... you'd be making about 300 kts TAS and would no doubt have the same mass airflow as at SL 8.5 gph. Mass airflow is a function of indicated airspeed which is dynamic pressure which is how many molecules are going past a point in a unit of time. Just a theory ... Jim S. Eric Ruttan wrote: > Ed > How do the Mass Air requirments change with altitude. For example, if the > fuel burn was 8.5gph and altitude was 25K would the mass air requirements > change do to thiner air? Would the lower temp make a difference? > > Thanks for your help. > > >> Homepage: http://www.flyrotary.com/ > >> Archive: http://lancaironline.net/lists/flyrotary/List.html