X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ispmxmta06-srv.windstream.net ([166.102.165.167] verified) by logan.com (CommuniGate Pro SMTP 5.1.11) with ESMTP id 2220206 for flyrotary@lancaironline.net; Mon, 30 Jul 2007 11:07:52 -0400 Received-SPF: pass receiver=logan.com; client-ip=166.102.165.167; envelope-from=montyr2157@alltel.net Received: from ispmxaamta05-gx.windstream.net ([71.29.244.202]) by ispmxmta06-srv.windstream.net with ESMTP id <20070730150709.PCZI29331.ispmxmta06-srv.windstream.net@ispmxaamta05-gx.windstream.net> for ; Mon, 30 Jul 2007 10:07:09 -0500 Received: from Thorstwin ([71.29.244.202]) by ispmxaamta05-gx.windstream.net with SMTP id <20070730150708.VZER15072.ispmxaamta05-gx.windstream.net@Thorstwin> for ; Mon, 30 Jul 2007 10:07:08 -0500 Message-ID: <002301c7d2bb$4cbde860$6501a8c0@Thorstwin> From: "M Roberts" To: "Rotary motors in aircraft" Subject: Best Renesis Auto intake length Date: Mon, 30 Jul 2007 10:07:08 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0020_01C7D291.63B844E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_0020_01C7D291.63B844E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable As with most things, there is no one best length. Answer depends on max = RPM, what you want to optimize, how much room you have, what prop is = used (fixed or variable), how much money you want to spend, etc. With a fixed pitch prop I liked my first system the best for a good = combination of climb rate & speed. Climb was at 6200 rpm. It had 16 - = 17" runner length and did use a Dynamic Chamber. Please don't make me = or Ed rehash the DC again : )=20 My current manifold only has about 10.5" runners and gives up a little = on climb rate but really starts to pull strongly above 7000 rpm. = "Cleanliness" is of course very important. Tracy Tracy, I promise not to make you and Ed rehash the dynamic chamber. ;-) I tried searching the archives for every combination of runner, length, = intake, tuning I could think of and the results were not exactly what I = was looking for. Now I'll search for dynamic chamber and see what shows = up. I was looking at my Renesis and thinking how nice it was that it was all = put together and there was nothing wrong with it. In a moment of = weakness I considered leaving it that way. Then after sleeping on it I = decided it had to come apart to fix the oil jets and de-carbon = everything.....so I'll just stick with plan A. The problem with my installation is the cowl is very tight and I only = have room for two options for intake length.=20 1.) Very short 9" with the carbs right against the ports. 2.) Very long 20"+ with the carbs on the other side of the engine. After reading about Ed's experience with the short intakes I started to = think maybe I should go with the longer solution, in addition it should = be better in cruise. The P-port should give enough power on the top end that an intake = optimized for mid range shouldn't hurt too bad. Of course a CS prop would solve most problems including any surplus cash = problem ;-). The short system would probably have a higher BSFC. As always....testing is the answer. Monty ------=_NextPart_000_0020_01C7D291.63B844E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

As with most things, = there is no one=20 best length. Answer depends on max RPM, what you want to optimize, = how=20 much room you have, what prop is used (fixed or variable), how much = money you=20 want to spend, etc.

With a fixed pitch prop = I liked my=20 first system the best for a good combination of climb rate & = speed. =20 Climb was at 6200 rpm. It had 16 - 17" runner length and did use a = Dynamic=20 Chamber. Please don't make me or Ed rehash the DC again : ) =

My current manifold = only has about=20 10.5" runners and gives up a little on climb rate but really starts to = pull=20 strongly above 7000 rpm. "Cleanliness" is of course = very=20 important.

Tracy

Tracy,

I = promise not to=20 make you and Ed rehash the dynamic chamber. ;-)

I = tried searching=20 the archives for every combination of runner, length, intake, tuning I = could=20 think of and the results were not exactly what I was looking for. Now = I'll=20 search for dynamic chamber and see what shows up.

I = was looking at=20 my Renesis and thinking how nice it was that it was all put together and = there=20 was nothing wrong with it. In a moment of weakness I considered leaving = it that=20 way. Then after sleeping on it I decided it had to come apart to fix the = oil=20 jets and de-carbon everything.....so I'll just stick with plan=20 A.

The problem with=20 my installation is the cowl is very tight and I only have room for two = options=20 for intake length.

1.) Very short 9"=20 with the carbs right against the ports.

2.) Very long=20 20"+ with the carbs on the other side of the engine.

After reading=20 about Ed's experience with the short intakes I started to think maybe I = should=20 go with the longer solution, in addition it should be better in=20 cruise.

The P-port should give enough power on = the top=20 end that an intake optimized for mid range shouldn't hurt too=20 bad.

Of course a CS prop would solve most=20 problems including any surplus cash problem ;-).

The short system would probably = have a higher=20 BSFC.

As=20 always....testing is the answer.

Monty

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