Return-Path: Received: from fed1rmmtao07.cox.net ([68.230.241.32] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 724559 for flyrotary@lancaironline.net; Thu, 10 Feb 2005 21:15:28 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.32; envelope-from=daveleonard@cox.net Received: from davidandanne ([68.101.147.215]) by fed1rmmtao07.cox.net (InterMail vM.6.01.04.00 201-2131-117-20041022) with SMTP id <20050211021443.TAP1747.fed1rmmtao07.cox.net@davidandanne> for ; Thu, 10 Feb 2005 21:14:43 -0500 From: "DaveLeonard" To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Re: Heating the Fuel Date: Thu, 10 Feb 2005 18:14:49 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_008F_01C50F9C.68AB78B0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_008F_01C50F9C.68AB78B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Tracy, I went and researched the boiling point of gasoline and you hit the nail on the head - the different components boil at different temperatures making the overall mix very unpredictable. Also, different manufacturers and grades boil at widely different temps. As expected, aviation fuel is more consistent and boils at a higher temperature. I never found a particular number but always a range of temperatures where components began to boil off. The spread of those ranges went something like: 70's-150's F for winter blend mogas, up to mid 100's-high 300's for avgas. The problem with boiling the fuel is that most of it will then escape out the vent before it can re-condense. I'm sure this will more than offset any fuel gains from drag-free cooling. Even moderately raising the temp (and vapor pressure) will probably cause excessive evaporative loss of the fuel. We have to face the fact the fuel is not an acceptable coolant for this application. That's OK, there is still Evans or water and the rest of the wing surface to be used. If we can cool our engines with a few square inches of frontal surface, I know there is enough cooling capacity in those wings to do most of that work. All we have to do is build it into the design of the aircraft. (simple as that) :-) Dave Leonard (also dreaming of drag free cooling) Boiling the fuel? Isn't this the same as trying to re-refine the gasoline? I think this would cause all sorts of stuff to be distilled out and clog the fuel line. My $.02 Wendell To amplify why vapor lock is not an issue here (assuming we get adequate "tank cooling"), my plan was to cool the oil which gets to a much higher temp than the coolant. I never got around to finding out the boiling point of gasoline (anyone here know?) but it was my HOPE that it would boil which would vastly increase the heat absorbed from the oil. When the gasoline "steam" returned to the tank, it would immediately cool and condense to it's liquid state, even if the tank was almost empty. Possible flaw is that some components of gasoline might be more volatile than others, remain in vapor state and escape from the tank vent. Tracy (still dreaming of drag free cooling) ------=_NextPart_000_008F_01C50F9C.68AB78B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Tracy, I went = and=20 researched the boiling point of gasoline and you hit the nail on the = head - the=20 different components boil at different temperatures making the overall = mix very=20 unpredictable. Also, different manufacturers and grades boil at = widely=20 different temps. As expected, aviation fuel is more consistent and = boils=20 at a higher temperature. I never found a particular number but = always a=20 range of temperatures where components began to boil off. The = spread of=20 those ranges went something like:

70's-150's F = for winter=20 blend mogas, up to

mid 100's-high = 300's for=20 avgas.

The problem = with boiling=20 the fuel is that most of it will then escape out the vent before it can=20 re-condense. I'm sure this will more than offset any fuel gains = from=20 drag-free cooling. Even moderately raising the temp (and vapor = pressure)=20 will probably cause excessive evaporative loss of the fuel. We = have to=20 face the fact the fuel is not an acceptable coolant for this = application. =20 That's OK, there is still Evans or water and the rest of the wing = surface to be=20 used.

If we can cool = our engines=20 with a few square inches of frontal surface, I know there is enough = cooling=20 capacity in those wings to do most of that work. All we have to do = is=20 build it into the design of the aircraft. (simple as = that) =20 :-)

Dave Leonard = (also=20 dreaming of drag free cooling)

Boiling the fuel? Isn't this the same as trying to = re-refine the=20 gasoline? I think this would cause all sorts of stuff to be = distilled out=20 and clog the fuel line. My $.02

Wendell

To amplify why vapor lock is not an issue here (assuming = we=20 get adequate "tank cooling"), my plan was to cool the oil which = gets to=20 a much higher temp than the coolant. I never got around = to=20 finding out the boiling point of gasoline (anyone here know?) but it = was my=20 HOPE that it would boil which would vastly increase the heat = absorbed from=20 the oil. When the gasoline "steam" returned to the tank, it = would=20 immediately cool and condense to it's liquid state, even if the tank = was=20 almost empty.

Possible flaw is that some components of gasoline might be more = volatile than others, remain in vapor state and escape from the tank = vent.

Tracy (still dreaming of drag free cooling)

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