X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 16 Jan 2009 09:01:58 -0500 Message-ID: X-Original-Return-Path: Received: from mail06.syd.optusnet.com.au ([211.29.132.187] verified) by logan.com (CommuniGate Pro SMTP 5.2.11) with ESMTPS id 3429127 for lml@lancaironline.net; Fri, 16 Jan 2009 07:02:49 -0500 Received-SPF: pass receiver=logan.com; client-ip=211.29.132.187; envelope-from=fredmoreno@optusnet.com.au Received: from Razzle ([202.139.5.198]) (authenticated sender fredmoreno) by mail06.syd.optusnet.com.au (8.13.1/8.13.1) with ESMTP id n0GC1qXn025583 for ; Fri, 16 Jan 2009 23:02:02 +1100 From: "Fred Moreno" X-Original-To: "Lancair Mail" Subject: FW: [LML] Lancair IV bragging rights - drag reduction suggestions? X-Original-Date: Fri, 16 Jan 2009 21:01:48 +0900 X-Original-Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002A_01C9781D.ADD3E6A0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6838 Importance: Normal Thread-Index: Acl3yor5xlEFsj5jT1Cwi8gbWcVBqQAA673g X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_002A_01C9781D.ADD3E6A0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Would you care to offer up a drag reduction prioritize list of improvements you have made ? =20 Tough question, Richard. I can not quantify a lot of the changes = because I made most of them during construction so no comparison testing was = possible. And I made LOT of changes. =20 I believe that the biggest improvement is also the most difficult: a complete re-engineering of the engine cooling air flow pathway from = modified inlets to plenum to patched air leaks, to adjustable cowl flaps that = control the outlet area and exit velocity. Total time invested with endless attention to detail in this area: maybe 1000 hours. It is not = recommended. Go flying instead. =20 But I would recommend the following place to start: leakage of cooling = air from the high pressure area above the engine. When you start looking = for leaks, they are EVERYWHERE. Some are very small but numerous, some are large, all are parasitic. You want the air to flow between all the = fins, full path length (no short cuts), and the oil cooler, and no where else. = =20 Smiley's NASA work in the 80's showed that the stock factory = installation (a turbo Piper Aztec with 250 HP Lycoming engines) of baffles, rubber and = sheet metal typically leaked 50% of the required cooling flow. That is, if = you need 100% to cool the engine, 150% was going into the inlets and out the outlets, pure waste in momentum drag. =20 =20 Most installations I have seen look OK on first blush, but with very = close inspection, virtually all leak like sieves. It takes extreme attention = to detail and a lot of patience to minimize the leakage. But the benefits = of fixing are substantial: reduced drag, and much cooler operating temperatures. =20 =20 When racing with Brent Regan and in studying many other aircraft and collecting anecdotal data from many, I concluded that a well built, = smooth, tight fitting Lancair IV had little room for improvement behind the firewall, so most of my work was in front of it. =20 =20 If there is enough interest, I will develop a picture catalog of all the drag reduction modifications I have made together with some descriptive words so other builders can pick and choose what they want to use. Some changes are easy. Some are very time consuming. And because I started = with many of the mods in place, I can not separate out the individual = benefits. But if enough people are interested, I will compile a catalog and let = Marv put it into the archives.=20 =20 Fred Moreno =20 -----Original Message----- From: marv@lancair.net [mailto:marv@lancair.net]=20 Sent: Friday, 16 January 2009 3:34 AM To: lml Subject: Re: [LML] Lancair IV bragging rights =20 Posted for "Richard T. Schaefer" : =20 Sounds great . =20 Would you care to offer up a drag reduction prioritize list of improvements you have made ? =20 =20 > Now that summer is well established Down Under, I was able to conduct = some > more flight testing. The air is smooth, winds gentle, and the bugs = have ------=_NextPart_000_002A_01C9781D.ADD3E6A0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

  Would you care to offer up = a drag reduction prioritize list of improvements

  you have made = ?

 

Tough question, Richard.  I can not quantify a lot of the changes because = I made most of them during construction so no comparison testing was = possible.  And I made  LOT of changes.

 

I believe that the biggest improvement is also the most difficult: a = complete re-engineering of the engine cooling air flow pathway from modified = inlets to plenum to patched air leaks, to adjustable cowl flaps that control the outlet = area and exit velocity.   Total time invested with endless attention to = detail in this area: maybe 1000 hours.  It is not recommended.  Go = flying instead.

 

But I would recommend the following place to start: leakage of cooling air = from the high pressure area above the engine.  When you start looking for = leaks, they are EVERYWHERE.  Some are very small but numerous, some are = large, all are parasitic.  You want the air to flow between all the fins, = full path length (no short cuts), and the oil cooler, and no where else. =

 

Smiley's NASA work in the 80's showed that the stock factory installation (a = turbo Piper Aztec with 250 HP Lycoming engines) of baffles, rubber and sheet metal typically leaked 50% of the required cooling flow.  That is, if you = need 100% to cool the engine, 150% was going into the inlets and out the = outlets, pure waste in momentum drag. 

 

Most installations I have seen look OK on first blush, but with very close inspection, virtually all leak like sieves.  It takes extreme = attention to detail and a lot of patience to minimize the leakage.  But the = benefits of fixing are substantial: reduced drag, and much cooler operating temperatures. 

 

When racing with Brent Regan and in studying many other aircraft and = collecting anecdotal data from many, I concluded that a well built, smooth, tight fitting = Lancair IV had little room for improvement behind the firewall, so most of my work = was in front of it. 

 

If there is enough interest, I will develop a picture catalog of all the = drag reduction modifications I have made together with some descriptive words = so other builders can pick and choose what they want to use.  Some = changes are easy.  Some are very time consuming.  And because I = started with many of the mods in place, I can not separate out the individual benefits.  But if enough people are interested, I will compile a = catalog and let Marv put it into the archives.

 

Fred Moreno

 

-----Original Message-----
From: marv@lancair.net [mailto:marv@lancair.net]
Sent: Friday, 16 January = 2009 3:34 AM
To: lml
Subject: Re: [LML] Lancair IV bragging rights

 

Posted for "Richard T. Schaefer" = <schaefer@rts-services.com>:

 

  Sounds great .

 

  Would you care to offer up a drag reduction prioritize list of = improvements

  you have made ?

 

 

> Now that summer is well established Down Under, I was able to conduct = some

> more flight testing.  The air is smooth, winds gentle, and the bugs = have

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