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 2703058 for flyrotary@lancaironline.net; Thu, 30 Oct 2003 11:26:12 -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 h9UGQ5R9029986 for ; Thu, 30 Oct 2003 11:26:09 -0500 (EST) Message-ID: <004401c39f01$ff637e40$1702a8c0@WorkGroup> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Intake manifold Date: Thu, 30 Oct 2003 11:22:19 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0041_01C39ED8.1486A9C0" 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_0041_01C39ED8.1486A9C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable .rr.com ----- Original Message -----=20 From: Finn Lassen=20 To: Rotary motors in aircraft=20 Sent: Thursday, October 30, 2003 8:55 AM Subject: [FlyRotary] Re: Intake manifold Ed, here's a highly theoretical question (as I have no plans to take = apart my engine again): will street porting the 1986 NA narrow the intake runner length curves = on the graph? On another note, I somehow have the idea that it's a bad idea to = combine the runners. For example Jim Mosur had big problems splitting = the water flow between his two radiators when he ran them in parallel. = Tracy has argued that it doesn't matter because on an intake system you = have a vacumn sucking in the air which would split it evenly. However, = not so with the DIE pulses. I could even imagine that the pulse, = preferring on path (one port) could even start to push out the air/fuel = charge out the other port. Over to you... Finn First to answer you question. Ta =3D Ad/Ars. There is a seperate Ta = for each Ad (angular difference) between intake port opening and other = rotor's intake closing. So since porting would increases Ad and = therefore Ta for each port , what porting all three would do is simple = to increase the Ta for each port. This in effect is simply changing = one of the parmeters of the parametric equation L =3D 12* = Vp*(Ad-Pd)/Ars, Ad to be specific. Therefore, you will likely shift all = the curves higher. Depends on how much you port one vs the other. The = position of the curve would change but not the shape or slope of the = curve. Don't know if that answered your question or not? In many cases I think it is probably not a good idea to combine = runners. The NA 13B has basically 3 different port timings (primary, = secondary and aux). That means that air flow, pulses what ever, would = have to be different for all three or at least Primary and the two = others during engine operation. While perhaps not impossible to get the = primary and secondary of the 13B NA ported the same, I seriously = question whether that would be the best approach. In fact, it might be = better to have three different DIE points that the 13B NA would appear = to offer.=20 For instance, the secondary port could give you DIE some place a bit = above your static rpm to assist in take off, perhpas your primary could = give you a sweet spot at your climb rpm and perhaps the Aux port could = give you a sweet spot at high cruise rpm. There are lots of things I/we = still don't know about the DIE as implemented in the 13B. Remember you = get as many DIE sweet spots as you have different port timing. So three = for the 13B NA and actually perhaps as many as 6 spots for the = variable/switchable DIE system on the 1990 NA. =20 I think you have to decide where you would like a bit more power. Me, = if I had to pick one DIE rpm, I would want it in the take off regime, I = want to get off the ground and as high as possible in as short amount of = time as possible. Other folks, in carnard types, might just want the = DIE for cruise, etc. Therefore, while I don't have any data to support this, but I would = be hesitant to combine primary and secondary runners on the 13B NA for = the reasons mentioned. On the other hand the primary and secondary on = the turbo (with the same timing) would have air flow (as well as DIE = pulses) all on the same timing and airflow cycle. So I can't see why it = wouldn't work to combine them. =20 You may get some disturbance of the airflow, but the "Y" won't have = much effect on the DIE pulse as it has no problem splitting and turning = corners since the pulse is really not flowing air, but an pulse of = energy translating across the distance by bumping one air molecule into = the next. Also for my plans for a variable intake manifold, two tubes are much = easier to deal with than four. If I could have figured out a way to = handle 4 tubes sliding I probably would have stayed with the four tubes. = However, for my turbo block, I decided the simplicity of using two = tubes (combining primary and secondary) outweighed any disadvantage - I = may prove myself wrong about that conclusion, but nothing ventured - = nothing gained. Ed Anderson ------=_NextPart_000_0041_01C39ED8.1486A9C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Finn=20 Lassen
Sent: Thursday, October 30, = 2003 8:55=20 AM
Subject: [FlyRotary] Re: Intake = manifold

Ed, here's a highly theoretical question (as I have no plans to = take=20 apart my engine again):
will street porting the 1986 NA narrow the = intake=20 runner length curves on the graph?

On another note, I somehow = have the=20 idea that it's a bad idea to combine the runners. For example Jim = Mosur had=20 big problems splitting the water flow between his two radiators when = he ran=20 them in parallel. Tracy has argued that it doesn't matter because on = an intake=20 system you have a vacumn sucking in the air which would split it = evenly.=20 However, not so with the DIE pulses. I could even imagine that the = pulse,=20 preferring on path (one port) could even start to push out the = air/fuel charge=20 out the other port.

Over to = you...

Finn

 First to answer you question.  Ta =3D = Ad/Ars.  There=20 is a seperate Ta for each Ad (angular difference) between intake port = opening=20 and other rotor's intake closing.  So since porting would =  increases=20 Ad and therefore Ta for each port , what porting all three would do is = simple=20 to increase the Ta for each port.   This in effect is simply = changing one of the parmeters of the parametric equation L =3D 12*=20 Vp*(Ad-Pd)/Ars, Ad to be specific.  Therefore, you will likely = shift all=20 the curves higher.  Depends on how much you port one =  vs the=20 other.  The position of the curve would change but not the shape = or slope=20 of the curve.  Don't know if that answered your question or=20 not?
 
In many cases I think it is = probably not a=20 good idea to combine runners.  The NA 13B has basically 3 = different port=20 timings (primary, secondary and aux).  That means that air flow, = pulses=20 what ever, would have to be different for all three or at least = Primary and=20 the two others during engine operation.  While perhaps not=20 impossible to get the primary and secondary of the 13B NA ported = the=20 same, I seriously question whether that would be the best = approach. =20 In fact, it might be better to have three different DIE points that = the 13B NA=20 would appear to offer. 
 
For instance, the secondary port = could give you=20 DIE some place a bit above your static rpm to assist in take off, = perhpas your=20 primary could give you a sweet spot at your climb rpm and perhaps the = Aux port=20 could give you a sweet spot at high cruise rpm.  There are lots = of things=20 I/we still don't know about the DIE as implemented in the 13B.  = Remember=20 you get as many DIE sweet spots as you have different port = timing.  So=20 three for the 13B NA and actually perhaps as many as 6 spots for the=20 variable/switchable DIE system on the 1990 NA. 
 
I think you have to decide where you = would like a=20 bit more power.  Me, if I had to pick one DIE rpm, I = would want it=20 in the take off regime, I want to get off the ground and as high as = possible=20 in as short amount of time as possible.  Other folks, in carnard = types,=20 might just want the DIE for cruise, etc.
 
  Therefore, while  I don't = have any=20 data to support this, but I would be hesitant to  combine primary = and=20 secondary runners on the 13B NA for the reasons mentioned.  On = the other=20 hand the primary and secondary on the turbo (with the same = timing)  would=20 have air flow (as well as DIE pulses) all on the same timing and = airflow=20 cycle.  So I can't see why it wouldn't work to combine = them. =20
 
You may get some disturbance of the = airflow, but=20 the "Y" won't have much effect on the DIE pulse as it has no problem = splitting=20 and turning corners since the pulse is really not flowing air, but an = pulse of=20 energy translating across the distance by bumping one air molecule = into the=20 next.
 
Also for my plans for a variable = intake manifold,=20 two tubes are much easier to deal with than four.  If I could = have=20 figured out a way to handle 4 tubes sliding I probably would have = stayed with=20 the four tubes.  However, for my turbo block, I decided the = simplicity of=20 using two tubes (combining primary and secondary) outweighed any = disadvantage=20 - I may prove myself wrong about that conclusion, but nothing ventured = -=20 nothing gained.
 
Ed Anderson
 
 
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