Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2900091 for flyrotary@lancaironline.net; Sun, 21 Dec 2003 21:50:59 -0500 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id hBM2oeow003450 for ; Sun, 21 Dec 2003 21:50:52 -0500 (EST) Message-ID: <006d01c3c835$e74e5c00$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Dumb intake question Date: Sun, 21 Dec 2003 21:47:03 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0068_01C3C80B.F86A0900" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0068_01C3C80B.F86A0900 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Sunday, December 21, 2003 8:57 PM Subject: [FlyRotary] Re: Dumb intake question What happens is when a Finite Amplitude Wave (FAW) hits a change in = cross-sectional area (like an opening from your tube to the atmoshpere = or a plenium - or a decrease to a closed tube) energy is reflected back = down the tube. The amount depends on the extent of cross section change, = but opening to the atmosphere reflects most of the energy. If the = cross sectional area it sees is Larger then a FAW wave of the opposite = type is reflected. If the cross sectional area is smaller, a FAW wave = of the same type is reflected.=20 Hi Ed,=20 Thanks for an explanation that was a clear as it could possibly be. = Now that you have confirmed that the change of cross sectional area is = what triggers the bounce, I can get back to a question that I asked you = a few months ago (Kelly just asked the same one). =20 Back when Eddie was first being discussed, I asked if I could extend = the runner ahead of the TB, and have it count as part of the tuned = assembly. At the time, you said no, that it had to be after the TB. Is = that your final answer :-) =20 If tuning is possible prior to the TB, then a short manifold will work = great, and offer easy tuning of the length. =20 Thanks, Rusty (new cowl looks muuuuuch better) Well, can't quite recall the details of that e mail-must be age{:>). = If we were talking EDDIE then I may have just misunderstood what your = "ahead of the TB" was actually referring to. But, in any case, if I = stated that - then I claim the right to change my mind {:>). You can = tune to benefical effect by paying attention to the length. I had been focused on the port to port (different rotors) in the EDDIE = analysis and hadn't really tried the math on the stand-alone-port. = Also, I better understand how the pulse returning to its orginating port = would react depending on whether the port is open or closed. =20 But, its fairly clear to me that the strength of the effect is = probably not the magnitude of the port to port EDDIE effect as some = energy is lost on each bounce. Also, the port event that you rely on = "the A" pulse rather than primarily the "B" pulse in the type of = manifold you are talking about also is somewhat weaker. But, its = clearly worthwhile. I think I mentioned I found a 1970 Honda engineers work that showed a = boost in power based on "pulse" tuning AND his work was for returning = the pulse to the orginating port unlike the EDDIE concept. But, try to = keep the cross sectional area the same as much as you can until your = throttle body. Ed Anderson ------=_NextPart_000_0068_01C3C80B.F86A0900 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
 
From:=20 Russell=20 Duffy
Sent: Sunday, December 21, 2003 = 8:57=20 PM
Subject: [FlyRotary] Re: Dumb = intake=20 question

  What happens is when a = Finite=20 Amplitude Wave (FAW) hits a change in cross-sectional area (like an = opening=20 from your tube to the atmoshpere or a plenium - or a decrease to a = closed=20 tube) energy is reflected back down the tube. The amount depends on = the extent=20 of cross section change, but opening to the atmosphere reflects most = of the=20 energy.   If the cross sectional area it sees is Larger then a = FAW wave=20 of the opposite type is reflected.  If the cross sectional area = is=20 smaller, a FAW wave of the same type is reflected. 
 
 
Hi Ed,
 
Thanks for an explanation that was a clear = as it=20 could possibly be.  Now that you have confirmed that the change = of cross=20 sectional area is what triggers the bounce, I can get back to a = question that=20 I asked you a few months ago (Kelly just asked the same one). =20
 
Back when Eddie was first being discussed, = I asked if=20 I could extend the runner ahead of the TB, and have it count as part = of the=20 tuned assembly.  At the time, you said no, that it had to be = after=20 the TB.  Is that your final answer :-)  =20
 
If tuning is possible prior to the TB, then = a short=20 manifold will work great, and offer easy tuning of the length. =20
 
Thanks,
Rusty (new cowl looks muuuuuch=20 better)
 
Well, can't=20 quite recall the details of that e mail-must be age{:>). If we = were=20 talking EDDIE then I may have just misunderstood what your "ahead of = the TB"=20 was actually referring to.  But, in any case, if I stated that - = then I=20 claim the right to change my mind {:>).    You can = tune to=20 benefical effect by paying attention to the = length.
 
I had been focused on = the port to=20 port (different rotors) in the EDDIE analysis and hadn't really tried = the math=20 on the stand-alone-port.  Also, I better understand how = the pulse=20 returning to its orginating port would  react=20 depending on whether the port is open or closed. =20
 
But, its fairly clear to me that the = strength of the=20 effect is probably not the magnitude of the port to port EDDIE effect = as some=20 energy is lost on each bounce.  Also, the port event that you = rely on=20 "the A" pulse rather than primarily the "B" pulse in the type of = manifold you=20 are talking about also is somewhat weaker.  But, its clearly=20 worthwhile.
 
I think I mentioned I found a 1970 Honda = engineers=20 work that showed a  boost in power based on "pulse" tuning = AND his=20 work was for returning the pulse to the orginating port unlike the = EDDIE=20 concept.  But, try to keep the cross sectional area the same as = much as=20 you can until your throttle body.
 
Ed Anderson
 
 
 
 
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