Return-Path: Received: from pop018.verizon.net ([206.46.170.212] verified) by logan.com (CommuniGate Pro SMTP 4.1.4) with ESMTP id 2601868 for flyrotary@lancaironline.net; Wed, 24 Sep 2003 13:29:18 -0400 Received: from [65.239.57.243] ([67.225.117.24]) by pop018.verizon.net (InterMail vM.5.01.05.33 201-253-122-126-133-20030313) with ESMTP id <20030924172911.BKHK11703.pop018.verizon.net@[65.239.57.243]> for ; Wed, 24 Sep 2003 12:29:11 -0500 Mime-Version: 1.0 X-Sender: res0c5l1@incoming.verizon.net Message-Id: In-Reply-To: References: Date: Wed, 24 Sep 2003 10:29:01 -0700 To: "Rotary motors in aircraft" From: Ken Welter Subject: Re: [FlyRotary] turbo math Content-Type: multipart/alternative; boundary="============_-1147697891==_ma============" X-Authentication-Info: Submitted using SMTP AUTH at pop018.verizon.net from [67.225.117.24] at Wed, 24 Sep 2003 12:29:02 -0500 --============_-1147697891==_ma============ Content-Type: text/plain; charset="us-ascii" ; format="flowed" >Greetings, > >I did some searching around, and found the basic gas formulas at this page- >http://www.pmel.org/HandBook/HBpage20.htm > >For my measured temps: > > >MAP / temp F / RPM > >18" / 105 / 3000 > >20" / 128 / 4225 > >30" / 167 / 5000 > >36" / 196 / 5500 > >40" / 214 / 5700 > >44" / 228 / 5800 > > > >It appears that at my 36" MAP boost level, I have the same air >density that I would have at NA, on the same 90F ambient day. > > > >Unfortunately, this air density is only part of the problem. I'm >guessing that exhaust backpressure is as much, if not more of an >issue. This leaves me still thinking that I'll need 5-6 psi of >boost to break even with a good NA engine, but I'm becoming >more comfortable with those figures. > > > >Rusty (off to the hanger to see if I can find a place for Mr. intercooler) > > Hey Rusty let me run this one by you. I am planing to put a turbo on my coot and I plan to install a huge waist gate that will be used a a dump valve to shut the turbo down, also on the intake side I will have a bypass flapper valve that will let cool fresh air in when the turbo is shut down, most bigger turbo setups have these incase of a turbo failure. With this setup you can have your cake and eat it to, use the turbo when you need it but for economy cruise your better off without it and your not putting unnecessary ware and tare on the turbo, also a great safety factor as you will be coming down if you ever lose a turbo and with this just kick it in bypass mode. All of this shouldn't take up much space either. Ken Welter --============_-1147697891==_ma============ Content-Type: text/html; charset="us-ascii" Re: [FlyRotary] turbo math
Greetings,
 
I did some searching around, and found the basic gas formulas at this page- 
http://www.pmel.org/HandBook/HBpage20.htm
 
For my measured temps:
 
MAP / temp F / RPM
18" / 105 / 3000
20" / 128 / 4225
30" / 167 / 5000
36" / 196 / 5500
40" / 214 / 5700
44" / 228 / 5800
 
It appears that at my 36" MAP boost level, I have the same air density that I would have at NA, on the same 90F ambient day. 
 
Unfortunately, this air density is only part of the problem.  I'm guessing that exhaust backpressure is as much, if not more of an issue.  This leaves me still thinking that I'll need 5-6 psi of boost to break even with a good NA engine, but I'm becoming more comfortable with those figures.  
 
Rusty (off to the hanger to see if I can find a place for Mr. intercooler) 
 
  Hey Rusty let me run this one by you.
 I am planing to put a turbo on my coot and I plan to install a huge waist gate that will be used a a dump valve to shut the turbo down, also on the intake side I will have a bypass flapper valve that will let cool fresh air in when the turbo is shut down, most bigger turbo setups have these incase of a turbo failure.
 With this setup you can have your cake and eat it to, use the turbo when you need it but for economy cruise your better off without it and your not putting unnecessary ware and tare on the turbo, also a great safety factor as you will be coming down if you ever lose a turbo and with this just kick it in bypass mode.
  All of this shouldn't take up much space either.

 Ken Welter
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