Andrew,
I think Paul is right. There is a direct parallel in the mechanism he refers
to in the Concorde accident in Paris - there debris hit the very full tank
causing a segment of the wall to be blown out at the weakest point. It might
not have happened had the tanks not been brimmed.
With the Europa tank, what the Land Rover unscientific demonstration tells
us is that the tank can flex hugely without splitting. What any materials
scientist will tell us is that the material will have a limit to the tension
loads it can take: it is possible for a full tank taking an impact to split
in tension; that tension arises because the contents will not allow if to
flex.
Taking your can analogy: fill it with a dense foam (compressible) and throw
it against a wall, hard. It will likely not split. Fill it with liquid and
throw it similarly: it will likely split.
If the above stands scrutiny, it does tell us that brimming the tanks "just
because there is space so I might as well use it" is not always the wisest
policy if that fuel is not required.
Regards,
Jeremy
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Andrew Sarangan
Sent: 18 June 2007 04:01
Subject: Re: Europa-List: Fuel Tanks
I am not sure about that theory. It is easier to crush an empty soda
can than a full one. Air is more compressible than liquid. When a full
tank is impacted, the liquid will transfer that energy to all surfaces
with little or no compression. A partial tank on the other hand will
compress until the air inside is squeezed to match the liquid. By then
the tank might have undergone enough bending stress to break it. Again,
just a theory.
--- Paul McAllister <paul.mcallister@qia.net> wrote:
> <paul.mcallister@qia.net>
>
> Hi all,
>
> I recall watching Ivan Shaw's impromptu demonstration of a Landrover
> driving
> over a Europa fuel tank.
>
> I remember thinking at the time, wondering if it would fare as well
> if it
> was full of liquid. I suspect that the hydraulic pressure would
> easily
> rupture the tank, no matter what it was constructed of.
>
> I would offer up a hypothesis that a full tank in a Europa that was
> subjected to a high G load would rupture, but one that has had fuel
> burnt
> off would have sufficient airspace in it that could be compressed and
> not
> cause the tank to burst.
>
> Just a theory.
>
> Paul
>
>
>
>
>
>
>
|