Return-Path: Received: from imf23aec.mail.bellsouth.net ([205.152.59.71] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 573631 for flyrotary@lancaironline.net; Sun, 19 Dec 2004 23:20:24 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.71; envelope-from=sqpilot@bellsouth.net Received: from paul52u7f5qyav ([209.214.44.216]) by imf23aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with SMTP id <20041220041953.KSRR2382.imf23aec.mail.bellsouth.net@paul52u7f5qyav> for ; Sun, 19 Dec 2004 23:19:53 -0500 Message-ID: <001401c4e64b$24a5d540$d82cd6d1@paul52u7f5qyav> From: "Paul" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Short intake manifolds Date: Sun, 19 Dec 2004 22:19:47 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0011_01C4E618.D9516410" 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_0011_01C4E618.D9516410 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: Perry Mick=20 To: Rotary motors in aircraft=20 Sent: Sunday, December 19, 2004 11:26 AM Subject: [FlyRotary] Re: Short intake manifolds http://www.sacredcowburgers.com/ Tracy Crook wrote: 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). Cut Hi, Tracy....I have tried the short manifold, and I love it. I = left everything undisturbed except the manifold, a shorter throttle = cable, and longer wires to the injectors/throttle position sensor. The = engine started fine (as it did with the longer intake runners). That's = where the comparison ended. With the same factory default settings on = the ECU, the transition from idle to midrange was oh, so smooth. I used = to think the long intake manifold had a smooth transition...until I = tried the short Atkins intake manifold. A world of difference. With the = long intake runners, I could not advance above 1/2 throttle without the = engine bogging down. Now, I can go to full throttle, and the brakes will = not hold. Smooth from idle to full power. The best part....no after = shutdown fuel drips at all. With my 3 blade 64 x 78 prop, on three = trials, my static rpm's were 4800, 5000 and 4800 rpm's. Don't know what = rpm I will get once the prop unloads in flight, but it is such an = improvement over my long intake runners that always dripped fuel after = shutdown. I am finally excited about this aircraft. It's climb = performance was more like a Cessna 150 with the 4200 rpm's I was able to = obtain on it's first flight, and downwind only provided 140 knots = (didn't retract the nosegear). I am optomistic that the additional = static rpm's I am now getting should make a pleasant increase in = performance. I have to run a few more wires around and away from the = alternator belt, put adel clamps on the new fuel lines and finish = installing a shorter throttle cable, then I will be able to fly it and = see how much of an improvement I get. There is no doubt that I have a = lot more power (since I can now go to full throttle). Take care....Paul = Conner ------=_NextPart_000_0011_01C4E618.D9516410 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Perry = Mick=20
Sent: Sunday, December 19, 2004 = 11:26=20 AM
Subject: [FlyRotary] Re: Short = intake=20 manifolds

http://www.sacredcowburgers.com= /

Tracy=20 Crook wrote:
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=20 that it works well IF it is very "clean" (proper diameter runners, = no change=20 in cross sectional area, well matched to ports, etc, etc)  The = very=20 short 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=20 (so-so 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=20 this arrangement the "Holy Grail" of intake design.   I'd = call it=20 the "Sacred Cow".
 
Tracy   ( eat sacred cow for lunch).
Cut
 
Hi, Tracy....I have tried the = short manifold,=20 and I love it.  I left everything undisturbed except the = manifold, a=20 shorter throttle cable, and longer wires to the injectors/throttle = position sensor.  The engine started fine (as it did with the = longer=20 intake runners). That's where the comparison ended.  With the = same=20 factory default settings on the ECU, the transition from idle to = midrange=20 was oh, so smooth. I used to think the long intake manifold had a = smooth=20 transition...until I tried the short Atkins intake manifold. A = world of=20 difference.  With the long intake runners, I could not = advance above=20 1/2 throttle without the engine bogging down. Now, I can go to = full=20 throttle, and the brakes will not hold.  Smooth from idle to = full=20 power.   The best part....no after shutdown fuel drips = at=20 all.   With my 3 blade 64 x 78 prop, on three trials, my = static=20 rpm's were 4800, 5000 and 4800 rpm's.  Don't know what rpm I = will get=20 once the prop unloads in flight, but it is such an improvement = over my=20 long intake runners that always dripped fuel after shutdown.  = I am=20 finally excited about this aircraft.  It's climb performance = was more=20 like a Cessna 150 with the 4200 rpm's I was able to obtain on it's = first=20 flight, and downwind only provided 140 knots (didn't retract the=20 nosegear).  I am optomistic that the additional static rpm's = I am now=20 getting should make a pleasant increase in performance. I have to = run a=20 few more wires around and away from the alternator belt, put adel = clamps=20 on the new fuel lines and finish installing a shorter throttle = cable, then=20 I will be able to fly it and see how much of an improvement I = get. =20 There is no doubt that I have a lot more power (since I can now go = to full=20 throttle).  Take care....Paul=20 = Conner
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