X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 29 Dec 2010 21:21:36 -0500 Message-ID: X-Original-Return-Path: Received: from imr-ma03.mx.aol.com ([64.12.206.41] verified) by logan.com (CommuniGate Pro SMTP 5.3.11) with ESMTP id 4657806 for lml@lancaironline.net; Wed, 29 Dec 2010 10:56:08 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.206.41; envelope-from=rehbinc@aol.com Received: from mtaout-db06.r1000.mx.aol.com (mtaout-db06.r1000.mx.aol.com [172.29.51.198]) by imr-ma03.mx.aol.com (8.14.1/8.14.1) with ESMTP id oBTFtRP0006299 for ; Wed, 29 Dec 2010 10:55:27 -0500 Received: from user1-656b2de53 (adsl-068-157-189-102.sip.asm.bellsouth.net [68.157.189.102]) by mtaout-db06.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id DF2E1E0000CC for ; Wed, 29 Dec 2010 10:55:26 -0500 (EST) X-Original-Date: Wed, 29 Dec 2010 10:55:13 -0500 From: REHBINC Subject: Re: [LML] post crash fire control X-Original-To: "Lancair Mailing List" In-Reply-To: X-Original-Message-ID: References: X-Mailer: Nexus Desktop Client 3.3.6.1 MIME-Version: 1.0 Content-Type: MULTIPART/alternative; BOUNDARY=1ead1a19-dba1-422a-b444-b4a984ea0c1b Content-Transfer-Encoding: 8BIT x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:162339584:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d33c64d1b59ee1b7a X-AOL-IP: 68.157.189.102 --1ead1a19-dba1-422a-b444-b4a984ea0c1b Content-Type: TEXT/plain; charset=us-ascii If foam is used in the tanks, it will reduce the amount of ATOMIZED SPRAY produced by a crush/rupture of the fuel tank. This will help to reduce the chance of ignition, but not greatly as fuel will still trickle rapidly from the foam filled tank and quickly generate a flammable vapor in the area. In the event of significant travel after catastrophic tank failure, the foam could well make matters worse for the occupants as it would retain significant fuel for a short time. Without the foam, this fuel could be left behind, reducing the fire load at the point the aircraft comes to rest. Personally, I don't think foam is a worthwhile investment as a fire prevention tool in an aircraft. (At least for wing tanks) In my opinion, a better use for foam is to reduce slosh in the tank. The fuel dump idea makes much more sense to me. Sure the introduction of large quantities of air into the tank would result in a flammable vapor, but the failure pressure of the wing structure would be relatively low so the shock wave would be low as well. Ignition probably would not occur until after the tank was significantly ruptured anyway, so the confinement would be even less. Also the fiberglass/carbon wouldn't result in high energy missiles like heavier metals would, so the shrapnel danger would be lower as well. Finally, our testing on large tanks has shown that residual fuel in the bottom of a recently emptied tank generates a fuel rich/nonflammable layer in the bottom of the tank at a rate of about one foot per hour. Given the shallowness of a Lancair wing, a significant portion of the vapor space would likely be made nonflammable between the time the fuel was dumped and impact occurred. That's my two cents worth, Rob In a message dated 12/28/10 21:53:45 Eastern Standard Time, colyncase@earthlink.net writes: I'm wondering if anyone has researched/thought about fuel containment in the event of a crash. For example, I have foam in my aux tank because it was made by fuel safe and that's just the way they make their tanks. I didn't put any foam in my main tanks. But here's a possibility: http://www.crestfoam.com/intro.html A fuel dump option might also be interesting but that leaves highly explosive fumes in the tanks..... thoughts? Colyn -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --1ead1a19-dba1-422a-b444-b4a984ea0c1b Content-Type: TEXT/html; charset=utf-8 Content-Transfer-Encoding: 8BIT
If foam is used in the tanks, it will reduce the amount of ATOMIZED SPRAY produced by a crush/rupture of the fuel tank. This will help to reduce the chance of ignition, but not greatly as fuel will still trickle rapidly from the foam filled tank and quickly generate a flammable vapor in the area. In the event of significant travel after catastrophic tank failure, the foam could well make matters worse for the occupants as it would retain significant fuel for a short time. Without the foam, this fuel could be left behind, reducing the fire load at the point the aircraft comes to rest.
 
Personally, I don't think foam is a worthwhile investment as a fire prevention tool in an aircraft. (At least for wing tanks) In my opinion, a better use for foam is to reduce slosh in the tank.
 
The fuel dump idea makes much more sense to me. Sure the introduction of large quantities of air into the tank would result in a flammable vapor, but the failure pressure of the wing structure would be relatively low so the shock wave would be low as well. Ignition probably would not occur until after the tank was significantly ruptured anyway, so the confinement would be even less. Also the fiberglass/carbon wouldn't result in high energy missiles like heavier metals would, so the shrapnel danger would be lower as well.
 
Finally, our testing on large tanks has shown that residual fuel in the bottom of a recently emptied tank generates a fuel rich/nonflammable layer in the bottom of the tank at a rate of about one foot per hour. Given the shallowness of a Lancair wing, a significant portion of the vapor space would likely be made nonflammable between the time the fuel was dumped and impact occurred.
 
That's my two cents worth,
 
Rob
 
In a message dated 12/28/10 21:53:45 Eastern Standard Time, colyncase@earthlink.net writes:
I'm wondering if anyone has researched/thought about fuel containment in the event of a crash.
For example, I have foam in my aux tank because it was made by fuel safe and that's just the way they make their tanks.    I didn't put any foam in my main tanks.   But here's a possibility:

http://www.crestfoam.com/intro.html


A fuel dump option might also be interesting but that leaves highly explosive fumes in the tanks.....

thoughts?

Colyn


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