Return-Path: Sender: (Marvin Kaye) To: lml Date: Sat, 14 Jun 2003 14:55:46 -0400 Message-ID: X-Original-Return-Path: Received: from ms-smtp-03.tampabay.rr.com ([65.32.1.41] verified) by logan.com (CommuniGate Pro SMTP 4.1b8) with ESMTP id 2422211 for lml@lancaironline.net; Sat, 14 Jun 2003 14:36:02 -0400 Received: from 34025820001 (203.146.33.65.cfl.rr.com [65.33.146.203]) by ms-smtp-03.tampabay.rr.com (8.12.5/8.12.5) with SMTP id h5EIa04V019222 for ; Sat, 14 Jun 2003 14:36:00 -0400 (EDT) X-Original-Message-ID: <001801c332a3$ead8f150$cb922141@34025820001> From: "Charlie Kohler" X-Original-To: "LancairList" Subject: A/C X-Original-Date: Sat, 14 Jun 2003 14:36:49 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0015_01C33282.6399FFC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_0015_01C33282.6399FFC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Air Conditioning discussion; Asbestos suit is on---- let er rip!!! When I first started debated recommending the Airflow system, a major = detracting statement I always heard was, "I like the system, but I can't = stand all the drag from that scoop". I said it too! I insisted that = Bill Genevro put the scoop into a wind tunnel and test it. He did, and = it resulted in a much lower profile scoop. I like the results so I = installed it, and it's been absolutely great! Talk to anyone who has = one. =20 I began the testing and I reported the airspeed loss was less than five = knots. I was comparing data from a prop tested several years ago to a = post air conditioning installation test. There were few altitudes where = was zero knots lost. The highest I recorded was three knots.=20 The case could be made for the scoop in the Airflow system, that it = could provide a thermal boost. Air comes in cold and goes out hot. I = think that the P-51 boasted about a boost. But I think that's a = stretch. But in any case, it may be less than the Aero Cool system. Regarding Aero Cool, It is a mistake to think that holes in the = fuselage, blowing a large stream of hot air, provide no drag. They do! = Then, think about structure-- and the fact that we have a stressed skin = in a true monocoque* structure. A detailed stress analysis was = accomplished by Martin Holman when the airplane was initially developed. = To cut holes in the fuselage without redoing the stress analysis means = you're taking the "experimental" label literally. Has anyone looked at = the load path from the landing gear box/wing attach points to the = horizontal /vertical stabilizer? The Aero Cool system needs a large fan to cool the condenser. Consider = the electrical load--heavy wiring--heavy switches-- stress on alternator = and other components. The reason the system needs a fan is because NACA scoops do not work = where the fuselage area is reducing. Many builders have had a difficult = time locating the static ports at a +/- zero location. Too far forward = reads low--Too far aft reads high. Why??=20 The original NACA scoop for ventilation was on the leading edge of the = vertical stabilizer where the area is increasing. It could not be = located anywhere else, because the area was reducing.=20 If you put tufts on the NACA leading edge inside the scoops and fly the = airplane you will notice that air is coming out-- not going in. = Therefore fans must be used to counter this effect. Why are we working = against Mother nature here? =20 So in summary, I would say; The Aero Cool the system is heavier. (Extra equipment-fan. Heavier = wiring-fan. Heavier hoses- to run further aft.) =20 The Aero Cool system has drag by cutting holes in the fuselage and = blowing out hot air. Perhaps more drag than a scoop. (Questions arise as to structural strength. *) The Aero Cool system requires much more electrical service.=20 The Aero Cool system is much more complex to install. The Aero Cool system can take valuable baggage space. =20 The Aero Cool system moves the center of gravity aft. Will you be able = to carry backseat passengers in that rare event they're needed?=20 The Aero Cool system cost more to purchase--costs more to install. The Airflow systems unit needs no fan for the condenser. =20 It works well on the ground (the propeller provides the cooling airflow = over the condenser.) Therefore, it's lighter.=20 Condenser can be smaller because of the adequate Airflow in all = r=E9gimes.=20 Condenser is located outside the hull, and the heat associated in a = closed contained environment, therefore requiring less Airflow to cool = the condensate. Small loss in airspeed, that perhaps, may be the same as, or less than = the Aero Cool system, due to less weight, and no holes in the fuselage = providing turbulent Airflow over the fuselage and tail surfaces.=20 No sacrifice of space in the aft baggage compartment. =20 Much less cost. =20 Much simpler installation. And besides--doesn't that P-51 scoop looked neat!!!! =20 KISS Charlie Kohler *Monocoque and Truss-Type Construction=20 Monocoque is a French word meaning "single shell." It describes a type = of construction used on a plane's fuselage in which wooden hoops are = shaped over a curved form and then glued. Braces usually run the length = of the fuselage (semi-monocoque). Strips of plywood are glued over this = form. Most twisting and bending stresses are carried by the external = skin rather than by an open framework, eliminating the need for internal = bracing and resulting in a more streamlined airplane than with a = truss-type fuselage. The first wood monocoque structure was designed by = the Swiss Ruchonnet and applied to a Deperdussin monoplane racer by = Louis B=E9chereau in 1912. This term is sometimes used interchangeably = with "stressed-skin," which was originally meant to apply to the = structure of wings and tail-surfaces that were laid over metal spars. (Emphasis added) ------=_NextPart_000_0015_01C33282.6399FFC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Air Conditioning=20 discussion;

 

Asbestos suit is on---- = let er=20 rip!!!

 

When I first started = debated=20 recommending the Airflow system, a major detracting statement I always = heard=20 was, "I like the system, but I can't stand all the drag from that = scoop". I said=20 it too!  I=20 insisted that Bill Genevro put the scoop into a wind tunnel and test it. = He did,=20 and it resulted in a much lower profile scoop. I like the results so I = installed=20 it, and it's been absolutely great! Talk to anyone who has=20 one.  

 

 I began the testing = and I=20 reported the airspeed loss was less than five knots. I was = comparing data=20 from a prop tested several years ago to a post air conditioning = installation=20 test.  There=20 were few altitudes where was zero knots lost.  The = highest I=20 recorded was three knots.

 

The case could be made for = the scoop=20 in the Airflow system, that it could provide a thermal boost. Air = comes in=20 cold and goes out hot.  I think that the P-51 boasted about a=20 boost.  But I think that's a stretch. But in any case, it may be = less than=20 the Aero Cool system.

 

Regarding Aero Cool, It is a mistake to think = that holes=20 in the fuselage, blowing a large stream of hot air, provide no = drag.  They=20 do!  Then, think about = structure--=20 and the fact that we have a stressed skin in a true monocoque*=20 structure.  A detailed stress analysis was accomplished by Martin = Holman=20 when the airplane was initially developed. To cut holes in the = fuselage=20 without redoing the stress analysis means you're taking the = "experimental" label=20 literally. Has anyone looked at the load path from the landing gear = box/wing=20 attach points to the horizontal /vertical stabilizer?


The Aero Cool system = needs a=20 large fan to cool the condenser.  Consider the electrical = load--heavy=20 wiring--heavy switches-- stress on alternator and other = components.

The reason the system = needs a fan is=20 because NACA scoops do not work where the fuselage area is = reducing. Many=20 builders have had a difficult time locating the static ports at a +/- = zero=20 location. Too far forward reads low--Too far aft reads high. Why?? =

The original NACA scoop = for=20 ventilation was on the leading edge of the vertical stabilizer where the = area is=20 increasing. It could not be located anywhere else, because the area was=20 reducing. 

 If = you put tufts on=20 the NACA leading edge inside the scoops and fly the airplane you will = notice=20 that air is coming out-- not going in. Therefore fans must be used to = counter=20 this effect.  Why are we working against Mother nature = here?

 

So in summary, I would=20 say;

The Aero Cool the system = is heavier.=20 (Extra equipment-fan. Heavier wiring-fan.  Heavier hoses- to run = further=20 aft.) 

The Aero Cool system = has drag=20 by cutting holes in the fuselage and blowing out hot air. Perhaps more = drag than=20 a scoop.

      (Questions = arise as to=20 structural strength. *)

The Aero Cool system = requires much=20 more electrical service.

The Aero Cool system is = much more=20 complex to install.
The Aero Cool system can take valuable baggage=20 space. 

The Aero Cool system moves = the=20 center of gravity aft. Will you be able to carry backseat passengers in = that=20 rare event they're needed? 

The Aero Cool system = cost more to=20 purchase--costs more to install.

 

 

The Airflow systems unit = needs no=20 fan for the condenser. 

It works well on the = ground (the=20 propeller provides the cooling airflow over the condenser.)

Therefore, it's lighter. =

Condenser can be smaller = because of=20 the adequate Airflow in all r=E9gimes.

Condenser is located = outside the=20 hull, and the heat associated in a closed contained environment, = therefore=20 requiring less Airflow to cool the condensate.

Small loss in = airspeed, that=20 perhaps, may be the same as, or less than the Aero Cool system, = due to=20 less weight, and no holes in the fuselage providing turbulent Airflow = over the=20 fuselage and tail surfaces. 

No sacrifice of space in = the aft=20 baggage compartment. 

Much less cost.  =

Much simpler=20 installation.

 

And besides--doesn't that = P-51 scoop=20 looked neat!!!! 

 

KISS

 

Charlie=20 Kohler

 

 

*Monocoque = and Truss-Type=20 Construction

Monocoque is a = French word=20 meaning "single shell." It describes a type of construction used on a = plane's=20 fuselage in which wooden hoops are shaped over a curved form and then = glued.=20 Braces usually run the length of the fuselage (semi-monocoque). Strips = of=20 plywood are glued over this form. Most twisting and bending = stresses=20 are carried by the external skin rather than by an open framework, = eliminating=20 the need for internal bracing and resulting in a more streamlined = airplane than=20 with a truss-type fuselage. The first wood monocoque = structure was=20 designed by the Swiss Ruchonnet and applied to a Deperdussin monoplane = racer by=20 Louis B=E9chereau in 1912. This term is sometimes used interchangeably = with=20 "stressed-skin," which was originally meant to apply to the structure of = wings=20 and tail-surfaces that were laid over metal spars.
(Emphasis=20 added)
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