My motorhome had a couple of these, the= y 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> wrote:

Rob,

I ha= ve been thinking about this for some time and am glad the occasion has come u= p to discuss it.

I am building a Legacy and was try= ing 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.
<= br>
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 s= pot to dump the fuel.

I haven't real= ly 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 reliabili= ty or temperature and pressure limits, or how air will get into the tank to r= eplace the fuel, but it seams like the logical general direction?
=
Of course, one fear would be inadvertent dumping of the fuel o= r leaks.

Kevin Kossi

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

Colyn,

I am a forensic engineer and work quite a bit with fire and explos= ion 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 ta= nk 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 certainl= y will be. It is all a matter of time and temperature. In tank ships, you ne= ed 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 ex= plosion risk of the wing tanks (At least as long as I wasn't standing on it a= t the time!). My biggest concern would be the size of the fuel puddle the pl= ane came to rest in. A hundred gallons spread out on the runway could m= ake a real big fire real fast and would be difficult to survive if you were c= aught in the middle. Two cups of gas in the same scenario would be a much mo= re 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, c= olyncase@earthlink.net writes:

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

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

sounds like you are in this business?