Return-Path: Received: from email.netonecom.net ([209.172.26.13] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2927846 for flyrotary@lancaironline.net; Sun, 11 Jan 2004 11:51:58 -0500 Received: from johndown (C05-048.netonecom.net [216.65.188.48]) by email.netonecom.net (MOS 3.4.2-CR) with SMTP id CEF14393; Sun, 11 Jan 2004 11:51:54 -0500 (EST) Message-ID: <00a101c3d85c$724f5b20$30bc41d8@johndown> From: "john" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Radiator ducting Date: Sun, 11 Jan 2004 11:53:43 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0020_01C3D839.8FECC460" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 This is a multi-part message in MIME format. ------=_NextPart_000_0020_01C3D839.8FECC460 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Finn; I measured the inlets on the Lopresti, pipers at Oshkosh and the inlets were 5 1/4". JohnD ----- Original Message ----- From: Finn Lassen To: Rotary motors in aircraft Sent: Saturday, January 10, 2004 6:58 PM Subject: [FlyRotary] Re: Radiator ducting Thanks Ed. I guess it might be a good idea to go around with a measuring tape and look at planes with Sam James, Lu Presti and other round inlets cowls. But I guess 4.5 to 5" diameter is reasonable. I just measured my right radiator location. As you know, it is slanted fore/aft. One side (closest to prop hub) is 6" from prop edge, and the outboard edge is 13.5" from the prop edge. Coming from a 5" diameter inlet, what should the ducting look like? Bell or trumpet shaped? Or just direct lines from each point on the radiator circumference to nearest point on the inlet circle? Where do I find some 5" diameter tubing that will stretch to 12" diameter (or 9" x 10" square)? Finn Ed Anderson wrote: Finn, I would not go below about 18 square inches initially. I did reduce one of my duct openings to around 9-10 square inches, but left the other one at 24 square inches. Cooling is still fine (increased coolant temp by 5F), but I suspect the 24 Square inche one is carrying more of the load. K&W indicates that if your inlet opening is below a certain critical ratio then the losses go way up. Using the 95 square inches of the cores I calculated that 18 square inches was a good minimum. If you duct shape and outlet are close to optimum you could go smaller, but then things have got to be just right. I know that 24 square inches per core works great, and my total coolant inlet are is now at 33 square inches and still cooled on 90F day. I would pay particular attention to the lower lip of your inlet making certain it has a sort of airfoil curve to it so that air will find an easy path when the nose is up relative to the airstream (like during your climb). Don't have a clue as to whether the "round" inlets are better, some folks believe so. Van sort of poop pooed the idea at one dinner. Ed Anderson Homepage: http://www.flyrotary.com/ Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0020_01C3D839.8FECC460 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Finn; I measured the inlets on = the Lopresti,=20 pipers at Oshkosh and the inlets were 5 1/4". JohnD

----- Original Message -----
From:=20 Finn=20 Lassen
To: Rotary motors in = aircraft

Sent: Saturday, January 10, = 2004 6:58=20 PM

Subject: [FlyRotary] Re: = Radiator=20 ducting

Thanks Ed.

I guess it might be a good idea to go = around=20 with a measuring tape and look at planes with Sam James, Lu Presti and = other=20 round inlets cowls. But I guess 4.5 to 5" diameter is = reasonable.

I=20 just measured my right radiator location. As you know, it is slanted = fore/aft.=20 One side (closest to prop hub) is 6" from prop edge, and the outboard = edge is=20 13.5" from the prop edge. Coming from a 5" diameter inlet, what should = the=20 ducting look like? Bell or trumpet shaped? Or just direct lines from = each=20 point on the radiator circumference to nearest point on the inlet=20 circle?

Where do I find some 5" diameter tubing that will = stretch to=20 12" diameter (or 9" x 10" square)?

Finn

Ed Anderson = wrote:

Finn, I would not go below about 18 square inches initially. I did reduce = one of my duct openings to around 9-10 square inches, but left the other one = at 24 square inches. Cooling is still fine (increased coolant temp by 5F), = but I suspect the 24 Square inche one is carrying more of the load. = K&W indicates that if your inlet opening is below a certain critical ratio = then the losses go way up. Using the 95 square inches of the cores I = calculated that 18 square inches was a good minimum. If you duct shape and outlet = are close to optimum you could go smaller, but then things have got to be = just right. I know that 24 square inches per core works great, and my total coolant inlet are is now at 33 square inches and still cooled on 90F = day. I would pay particular attention to the lower lip of your inlet making = certain it has a sort of airfoil curve to it so that air will find an easy path = when the nose is up relative to the airstream (like during your climb). Don't have a clue as to whether the "round" inlets are better, some = folks believe so. Van sort of poop pooed the idea at one dinner. Ed Anderson

Homepage: http://www.flyrotary.com/ Archive: http://lancai= ronline.net/lists/flyrotary/List.html

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