X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTP id 4191048 for flyrotary@lancaironline.net; Wed, 31 Mar 2010 17:56:19 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id 1D3AE173852 for ; Thu, 1 Apr 2010 05:55:41 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 2F172BEC02E for ; Thu, 1 Apr 2010 05:55:39 +0800 (WST) Message-ID: <594CD0C8120448E88DC0E9D614B644F0@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Tuned lengths? Date: Thu, 1 Apr 2010 07:55:40 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001A_01CAD170.B94DB3A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100331-2, 03/31/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_001A_01CAD170.B94DB3A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ben, I agree tuning is necessary all designs are slightly different. On the subject of intake design, I don't think Mazda came up with their = fancy Renesis intake by chance, I'm pretty sure that would be a computer = proven design, well before production. George (down under) Lynn does such a great job at painting a very clear picture of the = dynamics of an internal combustion engine.. Thank you sir... As a side = note those of us using an engine in close to a steady state application = are very lucky because tuning the intake is alot easier then in a = application that has a wide powerband range. A coupleof sharp motor = tuners and a day or so on a good repeatable dyno can zero in on = acceptable intake design that should set a good baseline for what really = works. You can sliderule / use fancy computer programs and other methods = of determining optimum designs but nothing trumps real time data in a = running engine. Just my .02 cents worth. =20 Ben Haas www.haaspowerair.com -------------------------------------------------------------------------= ----- To: flyrotary@lancaironline.net Date: Wed, 31 Mar 2010 01:09:18 -0400 From: lehanover@gmail.com Subject: [FlyRotary] Tuned lengths? A "tuned" intake covers a wide Varity of techniques ranging for = Hermholtz, RAM, Dynamic Intake, Inertia, etc,. There are basically three = conceptually different approaches although they tend to merge under certain = conditions. You have the resonant tuning, the pulse tuning and the inertia turning concepts. However, truth be known all three phenomena occur in most = intake systems - it's a matter of emphasis. The thing that really complicates it is the fact that within any = induction or exhaust system you have Finite Amplitude Waves - the power of these = pulse makes a 135 db sound wave very puny - these pulses can actually pound = metal apart. They do not interact linearly as do "sound waves" - in fact = they can respond in what at first seems to be weird ways. For instance they = may reverse there "polarity" depending on whether they encounter an open = or closed termination. It has only been with the advent of digital computers has it been = practical to even try and model the effects of these waves in an induction = system. I find them fascinating. Here are a few references that some of you might find interesting. http://home.earthlink.net/~redcat/pulse_ram/theory.html http://www.motionsoftware.com/simtech.htm http://www.proracingsim.com/dynomationmainpage.htm http://www.audietech.com/DMfeaturetable.htm Ed Anderson Side intake port engines produce different tuned effects than do = Periphery ported intake engines.=20 Side exhaust ported engines produce different tuned effects than do = periphery ported exhaust engines. The most powerfull engine would be the Periphery intake and exhaust = ported engines.=20 Although the intake and exhaust open and close events are reported in = degrees of crankshaft rotation just like a side port engine, the periphery ports never actually = close. So, tuned lengths produce bigger changes than in the side ported = engine. So, one end of the tune length is virtually open all of the = time, and worse one end is exposed to changeing pressures all of the = time.=20 The overlap (Intake and exhaust open at the same time) is huge. So = exhaust back pressure can poison the intake quite badly.=20 In the side intake ported engine one end of the column is closed solid = by the side of the rotor. Intake and exhaust overlap may be minimal or = extensive. Column lengths produce crisp tuning. Overlap with peripheral = exhaust ports may have less effect. Exhaust back pressure can remove = much power. Side intake and exhaust Renesis) may have no overlap at all. The = center exhaust ports share an exit that is too large right at the port = face. Even with no overlap, the intake can be poisoned by exhaust gasses = being held in the chamber by a poor exhaust system. Exhaust system has = three outlets Possibly less sensitive to back pressure than other designs When = converted to a Periphery intake port, may still have low overlap.=20 Lynn E. Hanover.=20 =20 -------------------------------------------------------------------------= ----- Hotmail: Trusted email with powerful SPAM protection. Sign up now. ------=_NextPart_000_001A_01CAD170.B94DB3A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ben,
I agree tuning is necessary all designs are = slightly=20 different.
On the subject of intake design, I don't think = Mazda came=20 up with their fancy Renesis intake by chance, I'm pretty sure that would = be a=20 computer proven design, well before production.
George (down under)
Lynn=20 does such a great job at painting a very clear picture of the dynamics = of an=20 internal combustion engine.. Thank you sir... As a side note those of = us using=20 an engine in close to  a steady state application are very = lucky=20 because tuning the intake is alot easier then in a application that = has a wide=20 powerband range. A coupleof sharp motor tuners and a day or so on a = good=20 repeatable dyno can zero in on acceptable intake design that should = set a good=20 baseline for what really works. You can sliderule / use fancy computer = programs and other methods of determining optimum designs but nothing = trumps=20 real time data in a running engine. Just my .02 cents=20 worth.
 
Ben Haas
www.haaspowerair.com






To: flyrotary@lancaironline.net
Date: Wed, 31 Mar 2010 01:09:18=20 -0400
From: lehanover@gmail.com
Subject: [FlyRotary] Tuned=20 lengths?

A "tuned" intake covers a wide Varity of techniques ranging for=20 Hermholtz,
RAM, Dynamic Intake, Inertia, etc,.  There are = basically=20 three conceptually
different approaches although they tend to merge = under=20 certain conditions.
You have the resonant tuning, the pulse tuning = and the=20 inertia turning
concepts.  However, truth be known all three = phenomena=20 occur in most intake
systems - it's a matter of = emphasis.

The thing=20 that really complicates it is the fact that within any induction
or = exhaust=20 system you have Finite Amplitude Waves - the power of these = pulse
makes a=20 135 db sound wave very puny - these pulses can actually pound=20 metal
apart.  They do not interact linearly as do "sound = waves" - in=20 fact they can
respond in what at first seems to be weird = ways.  For=20 instance they may
reverse there "polarity" depending on whether = they=20 encounter an open or
closed termination.

It has only been = with the=20 advent of digital computers has it been practical
to even try and = model the=20 effects of these waves in an induction system.  I
find them=20 fascinating.

Here are a few references that some of you might = find=20 interesting.

http://h= ome.earthlink.net/~redcat/pulse_ram/theory.html

http://www.motionsoftw= are.com/simtech.htm

http://www.pr= oracingsim.com/dynomationmainpage.htm

http://www.audietech= .com/DMfeaturetable.htm


Ed=20 Anderson
Side intake port engines produce different tuned effects than do=20 Periphery ported intake engines.
 
Side exhaust ported engines produce different tuned effects than = do=20 periphery ported exhaust engines.
 
The most powerfull engine would be the Periphery intake and = exhaust=20 ported engines.
 
Although the intake and exhaust open and close events are = reported in=20 degrees of crankshaft rotation
just like a side port engine, the periphery ports never actually = close.=20 So, tuned lengths produce bigger changes than in the side ported = engine. So,=20 one end of the tune length is virtually open all of the time, and = worse one=20 end is exposed to changeing pressures all of the time.
 
The overlap (Intake and exhaust open at the same time) is huge. = So=20 exhaust back pressure can poison the intake quite badly.
 
In the side intake ported engine one end of the column is closed = solid by=20 the side of the rotor. Intake and exhaust overlap may be minimal or = extensive.=20 Column lengths produce crisp tuning. Overlap with peripheral exhaust = ports may=20 have less effect. Exhaust back pressure can remove much power.
 
Side intake and exhaust Renesis) may have no overlap at all. The = center=20 exhaust ports share an exit that is too large right at the port face. = Even=20 with no overlap, the intake can be poisoned by exhaust gasses being = held in=20 the chamber by a poor exhaust system. Exhaust system has three=20 outlets
 
Possibly less sensitive to back pressure than other designs When=20 converted to a Periphery intake port, may still have low overlap. =
 
Lynn E. Hanover.
 
 

 

Hotmail: Trusted email with powerful SPAM protection. Sign up=20 now. ------=_NextPart_000_001A_01CAD170.B94DB3A0--