My motorhome had a couple of these, they tend = to drip (ooze) a little after a time. Not good in = aviation.

Bob Mitchell

L320

Sent from my = iPad

On Jan 1, 2011, at 5:29 PM, Kevin Kossi <kevin@airforcemechanical.com<= /a>> wrote:

Rob,

I have been = thinking about this for some time and am glad the occasion has come up = to discuss it.

I am building a Legacy and was = trying to figure out how to incorporate a dump valve into each wing to = dump the fuel for certain cases of emergency landings or imminent = crash.

So far I came up with this = valve:
<dump valve.jpg>

they = offer it with a stainless steel paddle in 2" & 3", one could be = mounted at the bottom of each wing at the lowest spot to dump the = fuel.

I haven't really done much = research into wether or not the aviation industry offers such a valve, = or the compatibility of the materials with the fuel or the reliability = or temperature and pressure limits, or how air will get into the tank to = replace the fuel, but it seams like the logical general = direction?

Of course, one fear would be = inadvertent dumping of the fuel or = leaks.

Kevin Kossi

On Dec 31, = 2010, at 1:10 AM, REHBINC wrote:

Colyn,

I am a forensic engineer and work quite a bit with fire and = explosion as well as mechanical/structural failure.

If I had a way to drain the fuel before crashing, I would get the = tanks as dry as possible. A couple ounces of gasoline trapped somewhere = in the tank would be plenty to make the space fuel rich. It isn't = realistic to expect the entire tank to be fuel rich before impact, but a = portion of it certainly will be. It is all a matter of time and = temperature. In tank ships, you need around 2 gallons or so to make = the space fuel rich. Frequently there is more than this trapped behind = the tank scale.

For the reasons stated earlier, I wouldn't be too concerned about = an explosion risk of the wing tanks (At least as long as I wasn't = standing on it at the time!). My biggest concern would be the size of = the fuel puddle the plane came to rest in. A hundred gallons spread out = on the runway could make a real big fire real fast and would be = difficult to survive if you were caught in the middle. Two cups of gas = in the same scenario would be a much more survivable = situation.

Another benefit of draining the tanks before impact is the = reduction in gross weight and therefore stall/impact speed.

Rob

In a message dated 12/30/10 20:10:11 Eastern Standard Time, colyncase@earthlink.net = writes:

Rob, interesting info.=20
So sounds like if you do have a quick drain, you don't want to = completely empty it.

I have no idea how to build a quick drain that would not create = some leakage risk.

sounds like you are in this business?

=