X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 30 Dec 2010 20:09:13 -0500 Message-ID: X-Original-Return-Path: Received: from mta21.charter.net ([216.33.127.81] verified) by logan.com (CommuniGate Pro SMTP 5.3.11) with ESMTP id 4658920 for lml@lancaironline.net; Thu, 30 Dec 2010 12:11:39 -0500 Received-SPF: pass receiver=logan.com; client-ip=216.33.127.81; envelope-from=troneill@charter.net Received: from imp11 ([10.20.200.11]) by mta21.charter.net (InterMail vM.7.09.02.04 201-2219-117-106-20090629) with ESMTP id <20101230171104.ORXL3705.mta21.charter.net@imp11> for ; Thu, 30 Dec 2010 12:11:04 -0500 Received: from [192.168.1.100] ([75.132.241.174]) by imp11 with smtp.charter.net id pVB31f0063mUFT705VB3FH; Thu, 30 Dec 2010 12:11:03 -0500 X-Authority-Analysis: v=1.0 c=1 a=fiSMRbF_xuEA:10 a=5Up8faWwAAAA:8 a=HG7oYs3SAAAA:8 a=Ia-xEzejAAAA:8 a=hg6rmbRASAqcQKFgWswA:9 a=BohI8rX6OTUqzLwyyPcA:7 a=vC74ZldnharEvBJOoLtezUKaAzIA:4 a=CjuIK1q_8ugA:10 a=7FQvRl5cvzsA:10 a=CVU0O5Kb7MsA:10 a=v6MMM96S_sUA:10 a=MB9uK3sXHhSuInLpcd8A:9 a=HCd0wHVCBWDqblzQZwQA:7 a=40TPdIsdmy8ujrC9UPZC1v29Z5EA:4 From: Terrence O'Neill Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: multipart/alternative; boundary=Apple-Mail-16--258233065 Subject: Re: [LML] Re: post crash fire control X-Original-Date: Thu, 30 Dec 2010 11:11:03 -0600 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <24BAC354-A7B8-4699-A2C0-173EEA3B729B@charter.net> X-Mailer: Apple Mail (2.1082) --Apple-Mail-16--258233065 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Two more cents worth: The only safe way is to be able to instantly turn the plane into a = glider -- that is, drop the fuel, tank and all. This has to be done in = initial design of the airframe. I did this in my Magnum Pickup = bushplane. All fuel was carried in a tank under the floor, and one = Parker quick-release connector fuel line. Pull one (safety-wired) = lever by the left leg and the tank and fuel fell away. Never had to use = it, but it dropped okay in the hangar test. Terrence L235/320 N211AL =20 On Dec 29, 2010, at 8:21 PM, REHBINC wrote: > 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. > =20 > 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. > =20 > 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. > =20 > 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. > =20 > That's my two cents worth, > =20 > Rob > =20 > 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.=20 > 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:=20 >=20 > http://www.crestfoam.com/intro.html=20 >=20 >=20 > A fuel dump option might also be interesting but that leaves highly = explosive fumes in the tanks.....=20 >=20 > thoughts?=20 >=20 > Colyn=20 >=20 >=20 > --=20 > For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html=20 > =20 --Apple-Mail-16--258233065 Content-Transfer-Encoding: 7bit Content-Type: text/html; charset=us-ascii Two more cents worth:
The only safe way is to be able to instantly turn the plane into a glider -- that is, drop the fuel, tank and all.  This has to be done in initial design of the airframe.  I did this in my Magnum Pickup  bushplane.  All fuel was carried in a tank under the floor, and one Parker quick-release connector fuel line.  Pull one (safety-wired)  lever by the left leg and the tank and fuel fell away.  Never had to use it, but it dropped okay in the hangar test.
Terrence
L235/320  N211AL

 
On Dec 29, 2010, at 8:21 PM, REHBINC wrote:

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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