Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 374549 for flyrotary@lancaironline.net; Sun, 22 Aug 2004 19:21:56 -0400 Received-SPF: none receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from EDWARD (cpe-069-132-183-211.carolina.rr.com [69.132.183.211]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i7MNIOPg007208 for ; Sun, 22 Aug 2004 19:18:25 -0400 (EDT) Message-ID: <003601c4889e$55b01570$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Compressor maps Date: Sun, 22 Aug 2004 19:18:29 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0033_01C4887C.CE6786F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0033_01C4887C.CE6786F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks for the info, John A T04 V2 is one of the two I had narrowed my preferred choice for a = turbo compressor wheel for the 13B. That is if I ever went turbo. High compression rotors really do not affect airflow except in the sense = you might get a bit more power and therefore rpm and therefore airflow. = But our positive displacement pump only cares about moving the air in = approx 40 cid gulps inthrough the intake and out through the exhaust = what we do to in in-between does not materially affect the air flow = (short of forced induction of some sort). A certain Aussie gent would argue that it doesn't matter whether you use = high compression pistons/rotor or low compression, its the combustion = chamber pressure that counts. If it stays below certain limits then no = detonation, if above then "BANG!". How it gets to that point is = immaterial. While in fact many folks do use low compression pistons if = they intend on running high boost as a safety margin. However, = frequently the low compression causes the bottom end performance to = suffer if over done. The argument would go that you will get just as = much power from the same combustion chamber pressure level before = combustion starts regardless how that pressure got to that point (the = engine doesn't know). So high compression pistons would mean less boost = is needed to reach that magic pressure point. =20 Since less boost means less heating of the air charge an argument could = probably be made that a lower boost level with high compression rotors = might be less prone to detonation that an engine using low compression = rotors and high boost (and therefore higher inlet temps). Humm, does = this mean If I use high compression rotors and less boost that perhaps I = would not need a intercooler?? But, I would have to say that a margin for error is somewhat more = important in our case than perhaps a automobile. =20 Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: John Slade=20 To: Rotary motors in aircraft=20 Sent: Sunday, August 22, 2004 3:18 PM Subject: [FlyRotary] Re: Compressor maps >An Aussi company is making some modifications to the stock turbo = which make it much better suited for=20 >our aircraft needs in my opinion. =20 Ed, Thanks for the ongoing education. Max at ATS says my turbo is equivalent to a T04-V2 as in the attached = map. I, also, am trying to get my head around CFM, AR and Density Altitude = so I can find the island, or at least stay on the map. :) One thing I was wondering - does having high compression rotors change = the airflow of the engine at a certain rpm? John (turbo last seen in LA) -------------------------------------------------------------------------= ----- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0033_01C4887C.CE6786F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks for the info, John
 
A T04 V2 is one of the two I had = narrowed my=20 preferred choice for a turbo compressor wheel for the 13B.  That is = if I=20 ever went turbo.
High compression rotors really do not = affect=20 airflow except in the sense you might get a bit more power and therefore = rpm and=20 therefore airflow.  But our positive displacement pump only cares = about=20 moving the air in approx 40 cid gulps inthrough the intake and out = through the=20 exhaust what we do to in in-between does not materially affect the air = flow=20 (short of forced induction of some sort).
 
A certain Aussie gent would argue that = it doesn't=20 matter whether you use high compression pistons/rotor or low = compression, its=20 the combustion chamber pressure that counts.  If it stays below = certain=20 limits then no detonation, if above then "BANG!".  How it gets to = that=20 point is immaterial.  While in fact many folks do use low = compression=20 pistons if they intend on running high boost as a safety margin.  = However,=20 frequently the low compression causes the bottom end performance to = suffer if=20 over done.  The argument would go that you will get just as much = power from=20 the same combustion chamber pressure level before combustion starts = regardless=20 how that pressure got to that point (the engine doesn't know).  So = high=20 compression pistons would mean less boost is needed to reach that magic = pressure=20 point. 
 
Since less boost means less heating of = the air=20 charge an argument could probably be made that a lower boost level with = high=20 compression rotors might be less prone to detonation that an engine = using low=20 compression rotors and high boost (and therefore higher inlet = temps). =20 Humm, does this mean If I use high compression rotors and less boost = that=20 perhaps I would not need a intercooler??
 
 
But, I would have to say that a margin = for error is=20 somewhat more important in our case than perhaps a automobile. =20
 
Ed
 
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 John=20 Slade
Sent: Sunday, August 22, 2004 = 3:18=20 PM
Subject: [FlyRotary] Re: = Compressor=20 maps

>An Aussi company is making some=20 modifications to the stock turbo which make it much better suited for=20
>our aircraft needs in my = opinion. =20
Ed,
Thanks for the=20 ongoing education.
Max = at ATS says my=20 turbo is equivalent to a T04-V2 as in the attached = map.
I, = also, am trying=20 to get my head around CFM, AR and Density Altitude so I can find = the=20 island, or at least stay on the map. :)
 
One = thing I was=20 wondering - does having high compression rotors change the airflow of = the=20 engine at a certain rpm?
John = (turbo=20 last seen in LA)
 

>>  Homepage: =20 http://www.flyrotary.com/
>>  Archive:  =20 = http://lancaironline.net/lists/flyrotary/List.html
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