Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2b8) with ESMTP id 324134 for flyrotary@lancaironline.net; Fri, 16 Jul 2004 19:51:12 -0400 Received-SPF: error receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from EDWARD (clt25-78-058.carolina.rr.com [24.25.78.58]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id i6GNoBiB012180 for ; Fri, 16 Jul 2004 19:50:12 -0400 (EDT) Message-ID: <004301c46b8f$a4377610$2402a8c0@EDWARD> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: New Scoop Date: Fri, 16 Jul 2004 19:50:14 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0040_01C46B6E.1CF15890" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1409 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0040_01C46B6E.1CF15890 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I would not argue with your assessment, Paul. I mainly put it up so you folks could see the source that many = "experts" use to tell you "Dummies" why what you have working - can't = possibly work {:>). I was offering a hypothesis as to why in some cases = the results "in-the-field" might be different from what NACA found in = the wind tunnels. I had not heard about the NACA supposedly not being = good for carburetors. My impression was that so long as there was not = back pressure (such as a cooler block will produce) anything that = created a lower than ambient pressure region behind the NACA duct (such = as engine intake or duct into a cabin) would cause it to work OK. I = know that the NACA duct that feeds cooling air into my cabin always has = a tremendous rush of air coming through it. Have to keep it closed off = most of the time at altitude or freeze my butt. Ed Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC ----- Original Message -----=20 From: sqpilot@earthlink=20 To: Rotary motors in aircraft=20 Sent: Friday, July 16, 2004 6:45 PM Subject: [FlyRotary] Re: New Scoop Hi, Ed.....I am of the opinion that the NACA report you provided is = old and out of date.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_0040_01C46B6E.1CF15890 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 I would not argue with your = assessment,=20 Paul.
 
  I mainly put it up so you folks = could see=20 the source that many "experts" use to tell you "Dummies"  why what = you have=20 working - can't possibly work {:>).  I was offering a hypothesis = as to=20 why in some cases the results "in-the-field" might be different from = what NACA=20 found in the wind tunnels.   I had not heard about the NACA = supposedly=20 not being good for carburetors.  My impression was that so long as = there=20 was not back pressure (such as a cooler block will produce) anything = that=20 created a lower than ambient pressure region behind the NACA duct (such = as=20 engine intake or duct into a cabin)  would cause it to work = OK.  I=20 know that the NACA duct that feeds cooling air into my cabin always has = a=20 tremendous rush of air coming through it. Have to keep it closed off = most of the=20 time at altitude or freeze my butt.
 
Ed
 
Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message -----
From:=20 sqpilot@earthlink
Sent: Friday, July 16, 2004 = 6:45 PM
Subject: [FlyRotary] Re: New = Scoop

Hi, Ed.....I am of the opinion that = the NACA=20 report you provided is old and out of date. Note that they also state = that the=20 NACA duct does not provide desireable recovery characteristics for = carburetors=20 on reciprocating engines.  Tell that to the many LongEZ builders = (myself=20 included) that found it to be very efficient in supplying air to our=20 carburetors in all attitudes, from cruise attitude to steep climbouts. = They=20 came up with a very nice, low drag inlet, but I don't think they spent = as much=20 time studying their creation or finding out it's true potential.  = Just my=20 experience, based upon a very succesful NACA duct feeding my MS carb = on my=20 Lycoming (ugh, sorry about that) powered LongEZ.  Paul Conner=20
----- Original Message -----
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Thursday, July 15, 2004 = 6:52=20 PM
Subject: [FlyRotary] Re: New=20 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=20 is one of the reasons that at least some canard installations = appear to=20 defy  both the conventional "wisdom" and the NACA = admonishment=20 that 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=20 area 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,=20 they 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=20 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 area. In fact, the pressure inside the cowl was = probably=20 slightly positive.   I don't know that would have made a=20 difference but seeing the success of John and others with it, I am = led to=20  believe that having the back of your cooler cores in = a lower=20 pressure area will enhance the probability of success in = using a NACA=20 duct. 
 
 
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=20 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=20 can be done.

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