Return-Path: Received: from [65.54.168.115] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 568550 for flyrotary@lancaironline.net; Wed, 15 Dec 2004 11:32:32 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.168.115; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 15 Dec 2004 08:32:01 -0800 Message-ID: Received: from 65.54.98.102 by BAY3-DAV11.phx.gbl with DAV; Wed, 15 Dec 2004 16:31:45 +0000 X-Originating-IP: [65.54.98.102] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Short intake manifolds Date: Wed, 15 Dec 2004 11:31:45 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0108_01C4E299.A8A006F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0009.2900 Seal-Send-Time: Wed, 15 Dec 2004 11:31:46 -0500 X-OriginalArrivalTime: 15 Dec 2004 16:32:01.0980 (UTC) FILETIME=[9AFA1FC0:01C4E2C3] This is a multi-part message in MIME format. ------=_NextPart_000_0108_01C4E299.A8A006F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Should be an interesting experiment Paul, can't wait to hear results. I tried a very short and now a medium-short manifold and find that it = works well IF it is very "clean" (proper diameter runners, no change in = cross sectional area, well matched to ports, etc, etc) The very short = runners gave up some power at climb rpm (FP prop) but did OK at cruise & = top end. The Medium-short version works about as well as my long (so-so = clean) manifold (~17" runners) and real good at top end. FWIW, my guess about your dripping throttle body is condensation on the = runners & throttle body walls. Gravity does the rest. Agravating the = problem is the "cool side injectors". Someone called this arrangement = the "Holy Grail" of intake design. I'd call it the "Sacred Cow". Tracy ( eat sacred cow for lunch). ----- Original Message -----=20 From: Paul=20 Subject: [FlyRotary] Re: Short intake manifolds Hi, Tom....I saved a few posts that addressed the problem you were = referring=20 to. The folks at Mistral also went into a lot of detail about it. = Problem=20 is, they were talking about the LONG intake runners, and having the=20 injectors at the far end, away from the engine. Power pulses problems, = incorrect fuel mixtures, etc. I am not going to try the short manifold, (since I received one = with=20 the bolt-on fuel/ignition package that I purchased from Atkins = Rotary), and=20 see how it works. I understand Dave Atkins has been using his for = quite some=20 time, with a lot of cross-country trips under his belt. Also, hearing Al's comments helps as well. What the heck....I = built an=20 experimental, so I guess it's expected I have the need to experiment a = little. Thanks for the input, Tom. Paul Conner ----- Original Message -----=20 From: "Tom" > To: "Rotary motors in aircraft" = > Sent: Tuesday, December 14, 2004 11:36 PM Subject: [FlyRotary] Re: Short intake manifolds > Paul, > There was a discussion here a few weeks ago regarding 'back pulses' = in the > intake manifold. Sorry, that may not be the correct term. IIRC, = seems a > short manifold may have issues, one being fuel droplets being = expelled=20 > the > opposite direction. Let me suggest the potential for it to pool in = your > 'outer chamber' and another potential for a backfire to ignite it.=20 > Hopefully > that is blatantly wrong so those who know will step in and = straighten it=20 > out. > You can tell by my terminology that I don't talk motors much. Also, = seems=20 > I > read many years ago that the one reason aircraft carburetors are = hung=20 > below the > motor is so any fuel remnants would fall out and evaporate and not = pool, > lessening chances that a backfire would have something to ignite. = This,=20 > just > idle chat. > > Tom > > > --- Paul > = wrote: >> My question is....With the >> short manifold putting the TWM throttlebody over the top of the = exhaust,=20 >> has >> Dave had any problems with fuel dripping out of the throttlebody = after >> engine shutdown? Also, did he put any kind of heat barrier between = the >> exhaust manifold and the throttlebody? > > > > __________________________________ > Do you Yahoo!? > Send holiday email and support a worthy cause. Do good. > http://celebrity.mail.yahoo.com > >>> Homepage: http://www.flyrotary.com/ >>> Archive: = http://lancaironline.net/lists/flyrotary/List.html >=20 >> Homepage: http://www.flyrotary.com/ >> Archive: = http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0108_01C4E299.A8A006F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Should be an interesting experiment Paul,  can't wait to hear=20 results.
 
 I tried a very short and now a medium-short manifold and find = that it=20 works well IF it is very "clean" (proper diameter runners, no change in = cross=20 sectional area, well matched to ports, etc, etc)  The very short = runners=20 gave up some power at climb rpm (FP prop) but did OK at cruise & top = end.  The Medium-short version works about as well as my long = (so-so clean)=20 manifold (~17" runners)  and real good at top end.
 
FWIW, my guess about your dripping throttle body is condensation on = the=20 runners & throttle body walls.  Gravity does the rest.  = Agravating=20 the problem is the "cool side injectors".  Someone called this = arrangement=20 the "Holy Grail" of intake design.   I'd call it the "Sacred=20 Cow".
 
Tracy   ( eat sacred cow for lunch).
----- Original Message -----
From: Paul
Subject: [FlyRotary] Re: Short = intake=20 manifolds

Hi, Tom....I saved a few posts that addressed the = problem you=20 were referring
to. The folks at Mistral also went into a lot of = detail=20 about it. Problem
is, they were talking about the LONG intake = runners, and=20 having the
injectors at the far end, away from the engine. Power = pulses=20 problems,
incorrect fuel mixtures, = etc.
     I am=20 not going to try the short manifold, (since I received one with =
the=20 bolt-on fuel/ignition package that I purchased from Atkins Rotary), = and=20
see how it works. I understand Dave Atkins has been using his for = quite=20 some
time, with a lot of cross-country trips under his=20 belt.
    Also, hearing Al's comments helps as = well. =20 What the heck....I built an
experimental, so I guess it's expected = I have=20 the need to experiment a
little. Thanks for the input, Tom.  = Paul=20 Conner

----- Original Message -----
From: "Tom" <tomtugan@yahoo.com>
To: = "Rotary=20 motors in aircraft" <flyrotary@lancaironline.net>
Sent:=20 Tuesday, December 14, 2004 11:36 PM
Subject: [FlyRotary] Re: Short = intake=20 manifolds


> Paul,
> There was a discussion here a = few=20 weeks ago regarding 'back pulses' in the
> intake = manifold.  Sorry,=20 that may not be the correct term.   IIRC, seems a
> = short=20 manifold  may have issues, one being fuel droplets being expelled =
> the
> opposite direction.   Let me suggest = the=20 potential for it to pool in your
> 'outer chamber' and another = potential=20 for a backfire to ignite it.
> Hopefully
> that is = blatantly=20 wrong so those who know will step in and straighten it
> = out.
>=20 You can tell by my terminology that I don't talk motors much.  = Also,=20 seems
> I
> read many years ago that the one reason = aircraft=20 carburetors are hung
> below the
> motor is so any fuel = remnants=20 would fall out and evaporate and not pool,
> lessening chances = that a=20 backfire would have something to ignite.  This,
> = just
>=20 idle chat.
>
> Tom
>
>
> --- Paul <sqpilot@bellsouth.net>=20 wrote:
>>  My question is....With the
>> short = manifold=20 putting the TWM throttlebody over the top of the exhaust,
>> = has
>> Dave had any problems with fuel dripping out of the=20 throttlebody after
>> engine shutdown?  Also, did he put = any=20 kind of heat barrier between the
>> exhaust manifold and the=20 throttlebody?
>
>
>
>=20 __________________________________
> Do you Yahoo!?
> Send = holiday=20 email and support a worthy cause. Do good.
> http://celebrity.mail.yahoo.com<= /A>
>
>>> =20 Homepage:  http://www.flyrotary.com/
>&= gt;> =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
>=20



>>  Homepage:  http://www.flyrotary.com/
>&= gt; =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
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