Return-Path: Received: from imf24aec.mail.bellsouth.net ([205.152.59.72] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 569374 for flyrotary@lancaironline.net; Wed, 15 Dec 2004 22:49:00 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.72; envelope-from=sqpilot@bellsouth.net Received: from paul52u7f5qyav ([209.214.44.73]) by imf24aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with SMTP id <20041216034828.MYKJ2421.imf24aec.mail.bellsouth.net@paul52u7f5qyav> for ; Wed, 15 Dec 2004 22:48:28 -0500 Message-ID: <000e01c4e322$128c8a10$492cd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Short intake manifolds Date: Wed, 15 Dec 2004 21:47:35 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0009_01C4E2EF.B07C3E10" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0009_01C4E2EF.B07C3E10 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks for the information, Tracy.....I think that by going to the short = manifold, I shouldn't have any more problem with residual fuel in the = intakes slowly running downhill and finding it's way out of the = throttlebody. I am glad to hear that shorter intake runners do, in fact = work, especially in cruise rpm, which is where I spend 90 percent of my = time while flying. I just want a simple setup, and I'm hoping this = might be one answer. Paul, getting rid of the sacred cow, Conner=20 ----- Original Message -----=20 From: Tracy Crook=20 To: Rotary motors in aircraft=20 Sent: Wednesday, December 15, 2004 10:31 AM Subject: [FlyRotary] Re: Short intake manifolds 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,=20 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=20 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. = > 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_0009_01C4E2EF.B07C3E10 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks for the information, Tracy.....I think = that by=20 going to the short manifold, I shouldn't have any more problem with = residual=20 fuel in the intakes slowly running downhill and finding it's way out of = the=20 throttlebody.  I am glad to hear that shorter intake runners do, in = fact=20 work, especially in cruise rpm, which is where I spend 90 percent of my = time=20 while flying.  I just want a simple setup, and I'm hoping this = might be one=20 answer. Paul, getting rid of the sacred cow, Conner
----- Original Message -----
From:=20 Tracy = Crook
Sent: Wednesday, December 15, = 2004 10:31=20 AM
Subject: [FlyRotary] Re: Short = intake=20 manifolds

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=20 it works well IF it is very "clean" (proper diameter runners, no = change in=20 cross sectional area, well matched to ports, etc, etc)  The very = short=20 runners gave up some power at climb rpm (FP prop) but did OK at cruise = &=20 top end.  The Medium-short version works about as well as my long = (so-so=20 clean) 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. =20 Agravating the problem is the "cool side injectors".  Someone = called this=20 arrangement the "Holy Grail" of intake design.   I'd call it = the=20 "Sacred 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,=20 and having the
injectors at the far end, away from the engine. = Power=20 pulses problems,
incorrect fuel mixtures,=20 etc.
     I am not going to try the short = manifold,=20 (since I received one with
the bolt-on fuel/ignition package = that I=20 purchased from Atkins Rotary), and
see how it works. I = understand Dave=20 Atkins has been using his for quite some
time, with a lot of=20 cross-country trips under his belt.
    Also, = hearing Al's=20 comments helps as well.  What the heck....I built an =
experimental,=20 so I guess it's expected I have the need to experiment a
little. = Thanks=20 for the input, Tom.  Paul Conner

----- Original Message = -----=20
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. =20 Sorry, that may not be the correct term.   IIRC, seems = a
>=20 short manifold  may have issues, one being fuel droplets being = expelled=20
> the
> opposite direction.   Let me suggest = the=20 potential for it to pool in your
> 'outer chamber' and another = potential for a backfire to ignite it.
> Hopefully
> = that is=20 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
> I
> read many years ago that = the one=20 reason aircraft carburetors are hung
> below the
> = motor is so=20 any fuel remnants would fall out and evaporate and not pool,
> = lessening chances that a backfire would have something to = ignite. =20 This,
> just
> idle chat.
>
>=20 Tom
>
>
> --- Paul <sqpilot@bellsouth.net>=20 wrote:
>>  My question is....With the
>> = short=20 manifold putting the TWM throttlebody over the top of the exhaust,=20
>> has
>> Dave had any problems with fuel = dripping out of=20 the throttlebody after
>> engine shutdown?  Also, did = he put=20 any kind of heat barrier between the
>> exhaust manifold = and the=20 throttlebody?
>
>
>
>=20 __________________________________
> Do you Yahoo!?
> = Send=20 holiday 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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