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Return-Path: <13brv3@bellsouth.net> Received: from imf17aec.mail.bellsouth.net ([205.152.59.65] verified) by logan.com (CommuniGate Pro SMTP 4.3c3) with ESMTP id 857848 for flyrotary@lancaironline.net; Wed, 06 Apr 2005 21:53:38 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.65; envelope-from=13brv3@bellsouth.net Received: from rd ([65.6.194.9]) by imf17aec.mail.bellsouth.net (InterMail vM.5.01.06.11 201-253-122-130-111-20040605) with ESMTP id <20050407015254.VUBT2001.imf17aec.mail.bellsouth.net@rd> for ; Wed, 6 Apr 2005 21:52:54 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] rule of thumb and RV-3 sizes- was Cooling Inlet Areas/Bernie's RV9 Date: Wed, 6 Apr 2005 20:52:36 -0500 Message-ID: <000001c53b14$78d2c1f0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C53AEA.8FFCB9F0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2527 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C53AEA.8FFCB9F0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Note: the exhaust area requirement is greater than the inlet = combination of oil and coolant due to the now considerable hotter air temperature. = Rule of thumb: Coolant air inlet opening for 200 HP coolant cooled engine ~60 = sq. in., oil inlet opening ~30 sq. in. equals a total opening of 90 sq. in. = A good place to start with exhaust opening is 1.4 times the inlets or 126 = sq. in. Close the exit area down with cowl flaps to as little as 80% of the inlet combination at cruise conditions! =20 Thanks for the rules of thumb Doug. I think something like this can be = more help to a new builder than all the math in the world, but we will have = to make sure the rule of thumb matches reality pretty well. =20 =20 I was just making a note in my log about the current inlet and outlet = sizes, and decided to compare them to the ones you posted. Here's the log = note, just as a point of reference. =20 As an added note, the cowl exit area now measures 6.5" tall, and an = average of about 19" wide. This gives 123.5 sq inches of exit area, where the = stock cowl exit was about 76 sq inches. The cowl cheek inlets are about 24 = sq in each, for 48 sq in total for coolant (throttle body takes air from this = was well). The current oil scoop is 30 sq in, and I suspect (hope) it's = going to be too big. =20 =20 Cheers, Rusty (being flooded from the new house built on a $%@& mound next to us grrrrr) =20 ------=_NextPart_000_0001_01C53AEA.8FFCB9F0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Note: the exhaust area requirement is greater than the = inlet=20 combination of oil and coolant due to the now considerable hotter air=20 temperature. Rule of thumb: Coolant air inlet opening for = 200 HP=20 coolant cooled engine ~60 sq. in., oil inlet opening ~30 sq. in. equals = a total=20 opening of 90 sq. in. A good place to start with exhaust opening = is 1.4=20 times the inlets or 126 sq. in. Close the exit area down with cowl = flaps=20 to as little as 80% of the inlet combination at cruise conditions!

Thanks for the=20 rules of thumb Doug. I think something like this can be more help=20 to a new builder than all the math in the world, but we will have = to make=20 sure the rule of thumb matches reality pretty=20 well.

I was just=20 making a note in my log about the current inlet and outlet sizes, and = decided to=20 compare them to the ones you posted. Here's the log note, just as = a point=20 of reference.

As=20 an added note, the cowl exit area now measures 6.5” tall, and an = average of=20 about 19” wide. = This gives 123.5 sq=20 inches of exit area, where the stock cowl exit was about 76 sq = inches. The cowl cheek inlets = are about 24=20 sq in each, for 48 sq in total for coolant (throttle body takes air from = this=20 was well). The current = oil scoop is=20 30 sq in, and I suspect (hope) it’s going to be too big.

Cheers,

Rusty (being=20 flooded from the new house built on a $%@& mound next to us=20 grrrrr)

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