Return-Path: Received: from fed1rmmtao04.cox.net ([68.230.241.35] verified) by logan.com (CommuniGate Pro SMTP 4.2.3) with ESMTP id 438823 for flyrotary@lancaironline.net; Thu, 30 Sep 2004 19:33:06 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.35; envelope-from=ALVentures@cox.net Received: from BigAl ([68.107.116.221]) by fed1rmmtao04.cox.net (InterMail vM.6.01.03.04 201-2131-111-106-20040729) with ESMTP id <20040930233233.VBFB1082.fed1rmmtao04.cox.net@BigAl> for ; Thu, 30 Sep 2004 19:32:33 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: oil coolers Date: Thu, 30 Sep 2004 16:32:40 -0700 Message-ID: <000001c4a745$c7338180$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C4A70B.1AD4A980" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C4A70B.1AD4A980 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Subject: [FlyRotary] Re: oil coolers =20 That looks wonderful, Al, BUT.... I have to wonder.. any loss of lift = or disruption with the use of that arrangement? Anyone else doing it that = way or are you the first that you know of..=20 Only one other that I know of that has flown, and it was on a lesser = scale - two aircraft coolers side by side. Similar location, just behind the = spar on a Velocity. The cooling was very effective, and no noticeable effect = on flight characteristics. I have about twice as large (long) an opening, = and on both sides (other wing has a coolant radiator of similar = configuration. Still it is a relative tiny amount of flow, and if the top fairings = maintain attached flow as planned, I'm confident the effect on aerodynamics will = not be an issue. But it is an experimental concept, that's for sure. Finally... temperature issues. I remember when we did post cure on the airframe on a hot july day, we coated it in black plastic in the yard. I dont recall seeing 200 degree F temps... what are you using to keep the = foam near the radiators from approaching that temp and post-curing = additionally? The coolers are supported by pads of coolmat insulation, and there are = air gaps everywhere else for some bypass cooling. There will no doubt be = some further post cure of the upper fairings. The temperatures will be an = issue on the ground, and I'll be watching this very closely during preflight testing. =20 I LIKE what I'm seeing but I am concerned too (I plan someday to build = my own, so I don't have to mooch off Chris all the time for airplane priveledges) =20 Dave =20 I to have been wondering about this. I'm actually going to be running a similar set up through a CFD program here in the next couple weeks [ = time permitting] So I should get a pretty good idea as to its effects.=20 I'd be very interested in what you find there. =20 My major question is how does/would/will it cool on the ground? Esp. in = a pusher configuration.. It will be interesting to hear once Al gets it flying.=20 That is certainly a good question. I was hoping that there would be sufficient natural convection to handle it for the oil cooler, but my = test runs on a hot day are indicating the core thickness, tight fin/tube = matrix, and angle of the oil cooler result in too little airflow, so-o-o. . = we'll see. And this is with the cooler out in the open, not in the wing root. = On the coolant side I have an in-cowl radiator as well where I can add a cooling fan if needed. The backup position on the oil side is the = addition of a compact oil-water heat exchanger inside the cowl. I'd say the odds favor both the fan and the heat exchanger. =20 My configuration would be a bit different as I'm going to try and put it right infront of the flap line.. and using it something like a SLOT in = the back of the wing.. the induction will be located a bit farther ahead.. = near the 30-40% chord Jarrett Johnson That should be better. I'm limited by the location of the spar, and I = can't cut any holes in that. =20 Al ------=_NextPart_000_0001_01C4A70B.1AD4A980 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Subject: [FlyRotary] Re: oil coolers

 

=

That = looks wonderful, Al, BUT.... I have to wonder..  any loss of lift or disruption  with the use of that arrangement? Anyone else doing it = that way or are you the first that you know of.. 

Only one other that I know of that has flown, and it was on a lesser scale = – two aircraft coolers side by side.  Similar location, just behind = the spar on a Velocity.  The cooling was very effective, and no noticeable = effect on flight characteristics.  I have about twice as large (long) an = opening, and on both sides (other wing has a coolant radiator of similar = configuration.  Still it is a relative tiny amount of flow, and if the top fairings maintain = attached flow as planned, I’m confident the effect on aerodynamics will not = be an issue.  But it is an experimental concept, that’s for = sure.

 Finally... temperature issues. I remember when we did post cure on the airframe on = a hot july day, we coated it in black plastic in the yard. I dont recall = seeing 200 degree F temps... what are you using to keep the foam near the radiators = from approaching that temp and post-curing additionally?

The coolers are supported by pads of coolmat insulation, and there are air = gaps everywhere else for some bypass cooling.  There will no doubt be some further = post cure of the upper fairings.   The temperatures will be an = issue on the ground, and I’ll be watching this very closely during = preflight testing.
 
I LIKE what I'm seeing but I am concerned too (I plan someday to build = my own, so I don't have to mooch off Chris all the time for airplane = priveledges)
 
Dave

  

I to = have been wondering about this. I'm actually going to be running a similar set up = through a CFD program here in the next couple weeks [ time permitting] So I = should get a pretty good idea as to its effects.

I’d be very interested in = what you find there.

 

My major = question is how does/would/will it cool on the ground? Esp. in  a pusher configuration.. It will be interesting to hear once Al gets it flying. =

That is certainly a good = question.  I was hoping that there would be sufficient natural convection to handle = it for the oil cooler, but my test runs on a hot day are indicating the core = thickness, tight fin/tube matrix, and angle of the oil cooler result in too little = airflow, so-o-o. . we’ll see.  And this is with the cooler out in the = open, not in the wing root.  On the coolant side I have an in-cowl = radiator as well where I can add a cooling fan if needed.  The backup position = on the oil side is the addition of a compact oil-water heat exchanger inside = the cowl.  I’d say the odds favor both the fan and the heat = exchanger.

 

My = configuration would be a bit different as I'm going to try and put it right infront of = the flap line.. and using it something like a SLOT in the back of the wing.. = the induction will be located a bit farther ahead.. near the 30-40% = chord

Jarrett = Johnson

That should be better.  = I’m limited by the location of the spar, and I can’t cut any holes in = that.

 

Al

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