Return-Path: Received: from scaup.mail.pas.earthlink.net ([207.217.120.49] verified) by logan.com (CommuniGate Pro SMTP 4.2b8) with ESMTP id 324103 for flyrotary@lancaironline.net; Fri, 16 Jul 2004 18:49:33 -0400 Received-SPF: pass receiver=logan.com; client-ip=207.217.120.49; envelope-from=sqpilot@earthlink.net Received: from user-33qt4v3.dialup.mindspring.com ([199.174.147.227] helo=Carol) by scaup.mail.pas.earthlink.net with smtp (Exim 3.33 #1) id 1BlbVk-0002TR-00 for flyrotary@lancaironline.net; Fri, 16 Jul 2004 15:49:00 -0700 Message-ID: <01d101c46b87$04591340$0000a398@Carol> From: "sqpilot@earthlink" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: New Scoop Date: Fri, 16 Jul 2004 17:45:58 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_01CE_01C46B5C.C08F3330" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2739.300 This is a multi-part message in MIME format. ------=_NextPart_000_01CE_01C46B5C.C08F3330 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi, Ed.....I am of the opinion that the NACA report you provided is old = and out of date. Note that they also state that the NACA duct does not = provide desireable recovery characteristics for carburetors on = reciprocating engines. Tell that to the many LongEZ builders (myself = included) that found it to be very efficient in supplying air to our = carburetors in all attitudes, from cruise attitude to steep climbouts. = They came up with a very nice, low drag inlet, but I don't think they = spent as much time studying their creation or finding out it's true = potential. Just my experience, based upon a very succesful NACA duct = feeding my MS carb on my Lycoming (ugh, sorry about that) powered = LongEZ. Paul Conner=20 ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Thursday, July 15, 2004 6:52 PM Subject: [FlyRotary] Re: New Scoop Looking at John's cooling set up, it appears that the cooler core = exits are in an excellent position to benefit from any lower pressure = region that may exist at the rear of the canard fuselage. =20 Its been my contention that this is one of the reasons that at least = some canard installations appear to defy both the conventional "wisdom" = and the NACA admonishment that NACA ducts are not well suited for = radiator cooling (or other uses that produce a back pressure). That is = - as in John's case - the successful arrangement appears to minimized = the back pressure across the core and perhaps benefits from a localized = area of lower than ambient pressure. Attached is an extract from a NACA report which makes it clear, that = at least in their opinion at the time, the NACA ducts were not suited = for radiators. But, as John and other's have shown, they can work very = effectively. So something they are doing must be different. The only = thing I can come up with is that the canard arrangement provides the = opportunity to benefit from what must be a lower pressure area behind = the fuselage as it moves through the air. =20 However, in my own personal experience in using a Naca duct in the = front of my cowling (in one of my five attempts to solve my oil cooler = problem) the results were consistent with the NACA assessment. It was = not successful for me. One of the differences is my oil cooler was approx 10" from the = firewall and did not have exit to a negative pressure area. In fact, the = pressure inside the cowl was probably slightly positive. I don't know = that would have made a difference but seeing the success of John and = others with it, I am led to believe that having the back of your cooler = cores in a lower pressure area will enhance the probability of success = in using a NACA duct. =20 My 0.02 worth. Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: John Slade=20 To: Rotary motors in aircraft=20 Sent: Thursday, July 15, 2004 6:48 PM Subject: [FlyRotary] Re: New Scoop >I believe that his cowling must extend down approximately 4-5 = inches to achieve that. Nope. The cowl is level with the fuselage floor, then curves = upwards. It's tight, but it can be done. John Slade (Got my EM2 .... manual) -------------------------------------------------------------------------= --- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html -------------------------------------------------------------------------= ----- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_01CE_01C46B5C.C08F3330 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi, Ed.....I am of the opinion that the = NACA report=20 you provided is old and out of date. Note that they also state that the = NACA=20 duct does not provide desireable recovery characteristics for = carburetors on=20 reciprocating engines.  Tell that to the many LongEZ builders = (myself=20 included) that found it to be very efficient in supplying air to our = carburetors=20 in all attitudes, from cruise attitude to steep climbouts. They came up = with a=20 very nice, low drag inlet, but I don't think they spent as much time = studying=20 their creation or finding out it's true potential.  Just my = experience,=20 based upon a very succesful NACA duct feeding my MS carb on my Lycoming = (ugh,=20 sorry about that) powered LongEZ.  Paul Conner
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Thursday, July 15, 2004 = 6:52=20 PM
Subject: [FlyRotary] Re: New = Scoop

Looking at John's cooling set up, it=20 appears  that the cooler core exits are in an excellent position = to=20 benefit from any lower  pressure region that may exist at = the rear=20 of the canard fuselage. 
 
Its been my contention that this = is one=20 of the reasons that at least some canard installations appear to=20 defy  both the conventional "wisdom" and the NACA = admonishment that=20 NACA ducts are not well suited for radiator cooling (or other uses = that=20 produce a back pressure).  That is - as in John's = case -=20  the successful arrangement appears to minimized the = back=20 pressure across the core and perhaps benefits from  a = localized area=20 of lower than ambient pressure.
 
Attached is an extract from a NACA = report which=20 makes it clear, that at least in their opinion at the time, the NACA = ducts=20 were not suited for radiators.  But, as John and other's have = shown, they=20 can work very effectively. So something they are doing must be=20 different.  The only thing I can come up with is that the canard=20 arrangement provides the opportunity to benefit from what must be a = lower=20 pressure area behind the fuselage as it moves through the=20 air.  
 
 However, in my own personal = experience in=20 using a Naca duct in the front of my cowling (in one of my five = attempts to=20 solve my oil cooler problem) the results were consistent with the NACA = assessment.  It was not successful for me.
 
  One of the differences is my = oil cooler=20 was approx 10" from the firewall and did not have exit to a negative = pressure=20 area. In fact, the pressure inside the cowl was probably slightly = positive.   I don't know that would have made a difference = but=20 seeing the success of John and others with it, I am led to =  believe that=20 having the back of your cooler cores in a lower pressure area = will=20 enhance the probability of success in using a NACA duct. =20
 
 
My 0.02 worth.
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 John=20 Slade
To: Rotary motors in = aircraft=20
Sent: Thursday, July 15, 2004 = 6:48=20 PM
Subject: [FlyRotary] Re: New=20 Scoop

>I believe that his cowling must extend down = approximately 4-5 inches to achieve that.

Nope. The = cowl is=20 level with the fuselage floor, then curves = upwards.

It's = tight, but it can=20 be done.

John Slade = (Got my EM2=20 .... manual)

>>  Homepage:  http://www.flyrotary.com/
>&= gt; =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html

>>  Homepage: =20 http://www.flyrotary.com/
>>  Archive:  =20 = http://lancaironline.net/lists/flyrotary/List.html
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