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Return-Path: <13brv3@bellsouth.net> Received: from imf20aec.mail.bellsouth.net ([205.152.59.68] verified) by logan.com (CommuniGate Pro SMTP 4.2b3) with ESMTP id 98072 for flyrotary@lancaironline.net; Mon, 31 May 2004 11:37:32 -0400 Received: from rad ([65.6.194.9]) by imf20aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040531153701.CPIZ18130.imf20aec.mail.bellsouth.net@rad> for ; Mon, 31 May 2004 11:37:01 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: intake #3 +150 rpm Date: Mon, 31 May 2004 10:37:04 -0500 Message-ID: <004001c44725$202e6510$6001a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0041_01C446FB.37585D10" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0041_01C446FB.37585D10 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Now that's more like it, Rusty. I do find it interesting the you get = less rpm with the sceet tubing. I gain approx 200 rpm when I use it, but = that may be because it gets its air from my chin scoop for the oil cooler and = I suspect the prop helps stuff a little more air in the tube. But, in = any case, your RV-3 should do very nicely with that static rpm - using = Tracy's prop I presume?=20 =20 Yes, still using Tracy's prop. Remember that my sceet tubing is only = 1.75", and there is one for each throat of the TB. There's also about 3 feet = of it per throat at the moment. I'm actually not surprised that it hurts performance now, but I was surprised that it didn't help more when I = removed it before. At speed, the ram air would probably equal the extra drag of = air in the hose, but we don't want to wasted the ram air like that :-)=20 =20 I'm considering a few options. I could re-work the rad duct to take a = 2.5" or 3" sceet tube, then split it into the two 1.75" inlets to the TB, hopefully with some EDDIE tuning in the mix. I could also try to keep = my current two 1.75" sceet tubes, but run them into a common plenum that = both TB throats would draw from. I think this would be easier since I don't = have to rework the rad duct (say it with me, I hate fiberglass), plus, I have = a lot of expensive 1.75" sceet tubing. Just don't know what to do yet, so I'll probably spend some significant time staring at the options today. = =20 A plenum may or may not assist with the airflow, convention wisdom is = that it does, but I think it depends on the rest of your intake, they have to play as a team or else they can hurt performance. Be interesting to see what difference it makes.=20 =20 The only thing I'm starting to worry about now, is the 1.75" OD runners = on the new intake (rev-2.1). I just have to wonder if those are going to = be big enough at 7000+ rpm. If I make it to rev-4, it won't matter :-)=20 =20 Cheers, Rusty (taking my camera today)=20 ------=_NextPart_000_0041_01C446FB.37585D10 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Now that's more like it, = Rusty. I do=20 find it interesting the you get less rpm with the sceet tubing. I = gain=20 approx 200 rpm when I use it, but that may be because it gets its air = from my=20 chin scoop for the oil cooler and I suspect the prop helps stuff a = little more=20 air in the tube. But, in any case, your RV-3 should do = very=20 nicely with that static rpm - using Tracy's prop I presume?

Yes, still using Tracy's = prop. Remember that=20 my sceet tubing is only 1.75", and there is one for each throat of = the=20 TB. There's also about 3 feet of it per throat at the = moment. I'm=20 actually not surprised that it hurts performance now, but I was = surprised that=20 it didn't help more when I removed it before. At speed, the ram = air would=20 probably equal the extra drag of air in the hose, but we don't want to = wasted=20 the ram air like that :-)

I'm considering a few options. I could = re-work=20 the rad duct to take a 2.5" or 3" sceet tube, then split it into = the two=20 1.75" inlets to the TB, hopefully with some EDDIE tuning in the = mix. =20 I could also try to keep my current two 1.75" sceet tubes, but run = them=20 into a common plenum that both TB throats would draw=20 from. I think this would be easier since I don't have to = rework the=20 rad duct (say it with me, I hate fiberglass), plus, I have a lot of = expensive 1.75" sceet tubing. Just don't know what to do yet, so = I'll=20 probably spend some significant time staring at the options=20 today.

A plenum may or may not assist = with the=20 airflow, convention wisdom is that it does, but I think it depends on = the rest=20 of your intake, they have to play as a team or else they can hurt=20 performance. Be interesting to see what difference it makes.

The only thing I'm starting to worry about now, = is the=20 1.75" OD runners on the new intake (rev-2.1). I just have to = wonder if=20 those are going to be big enough at 7000+ rpm. If I make it to = rev-4, it=20 won't matter :-)

Cheers,

Rusty (taking=20 my camera today)

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