Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.6) with ESMTP id 2703630 for flyrotary@lancaironline.net; Thu, 30 Oct 2003 19:31:32 -0500 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id h9V0UtR9005873 for ; Thu, 30 Oct 2003 19:31:00 -0500 (EST) Message-ID: <005001c39f45$bef20e00$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Intake manifold Date: Thu, 30 Oct 2003 19:27:15 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004D_01C39F1B.D3537020" 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_004D_01C39F1B.D3537020 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable =20 Ed; I would think that unless you were very careful a "Y" would have = significant effect because you have a sudden change in the = cross-sectional area which would dissipate the pulse energy and/or cause = a reflected pulse. No? Al =20 Hi Al, I agree, it appears that anytime you change the continunity of an = airflow it can have adverse effects. Based on what I have read, = Finite-Amplitude Waves (FAW) do indeed get reflected from a change in = cross-section. The extent of that reflection appears to be largely a = function of the degree of change in cross-sectional area. In = otherwords, if the change in cross-sectional area is small, the amount = of energy reflected is small, if change is large, reflected energy is = large. I am not certain what happens if a FAW encounters a "Y", in which the = cross sectional area of the two branches of the "Y" equal to the cross = sectional area of a single runner feeding them. The area of the = cross-section has not changed which could mean minimal enegry reflected, = but the form of it has changed from a single tube to two tubes. One = would think that is bound to have some effect. The question is "how = much?" I am hoping that keeping the cross sectional area for the "Y" and the = single runner feeding it the same will minimize any adverse effects. I = intend to do some more research to see if I can get a handle on effects = of a "Y" on the FAW. Then, of course, there is the "Y"s effect on the normal airflow. = Again, I believe that if the two ports are opening and closing at the = same time having air pushed down a single tube and then splitting into = two tubes may not be that bad. But, not having access to a dyno or the = instrumentation that would provide definitive answers, I guess I'll have = to try it to find out. Best Regards=20 Ed Anderson . =20 ------=_NextPart_000_004D_01C39F1B.D3537020 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Ed;

I would = think that=20 unless you were very careful a =93Y=94 would have significant effect = because you=20 have a sudden change in the cross-sectional area which would dissipate = the=20 pulse energy and/or cause a reflected pulse. = No?

Al

Hi Al,

I agree, it appears that anytime you change the=20 continunity of an airflow it can have adverse effects. Based on = what I=20 have read, Finite-Amplitude Waves (FAW) do indeed get reflected from a = change=20 in cross-section. The extent of that reflection appears to be=20 largely a function of the degree of change in cross-sectional = area. =20 In otherwords, if the change in cross-sectional area is small, the = amount of=20 energy reflected is small, if change is large, reflected energy is=20 large.

I am not certain what happens if a FAW encounters = a "Y", in=20 which the cross sectional area of the two branches of the "Y" equal to = the=20 cross sectional area of a single runner feeding them. The area = of the=20 cross-section has not changed which could mean minimal enegry = reflected,=20 but the form of it has changed from a single tube to two tubes. = One=20 would think that is bound to have some effect. The question is = "how=20 much?"

I am hoping that keeping the cross sectional area for=20 the "Y" and the single runner feeding it the same will = minimize any=20 adverse effects. I intend to do some more research to see if I = can get a=20 handle on effects of a "Y" on the FAW.

Then, of course, there is the "Y"s effect on the = normal=20 airflow. Again, I believe that if the two ports are opening and = closing=20 at the same time having air pushed down a single tube and then = splitting into=20 two tubes may not be that bad. But, not having access to a dyno = or the=20 instrumentation that would provide definitive answers, I guess I'll = have to=20 try it to find out.

Best Regards

Ed Anderson

.

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