re: fuel tank fitting into the Cockpit module
Hi everyone of the Europa-Net,
In Dec. of last year I received the original fuel tank with my
Stage III kit. In early summer I poured some car fuel into it
and let it sit for 6 weeks.
When I tried it into the CM (Cockpit module) it defenitely was
too big and a call to Roger was in order. He promptly sent me
a new one which had two improvements over the old one besides
it being smaller in overall dimensions: The fuel vent outlet is
on the side of the fuel filler hole eliminating the need for the
slot on the other side (and that screetching sound it makes when
you pushed in the old tank) and side-supporters in the form of
angular troughs eliminating some of those big deformations you
have on the old tanks that form on the big thin areas of the tank.
Well, I filled the tank again and let sit for four weeks this
time and after installing all the outlet fittings pushed it into
its position. It fit well - almost too well, being overall smaller
than necessary.
At that point I decided to try the old tank in again to compare
and to show a visiting friend how much bigger it was, but alas
it fit well ! All the bulged areas had vanished and it was a perfect
fit. What had happened ? Over the weeks of being exposed to cool
air without any fuel fumes the tank had shrunk back. This is probably
not a problem during active life of the airplane, because an unusable
rest of fuel will be left in there releasing vapours to keep the
material happily expanded. But keep in mind that the material lives
and I will of course not install the old tank since it will
explode the plane after getting fuel again.
My concern is the time after installation of the new tank - as it
gets no fuel for quite a while, it will shrink and I wonder whether
that could harm the layups in the saddle area ?
Also, as the new tank is smaller the bracket layups do have to bridge
quite a gap (approx 1 cm) thus giving the fully filled tank quite
some lever during a hard landing. I will probably reinforce the
layups in the saddle area for that reason.
Happy building,
Thomas Scherer
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