Hi,
Shortly before start of taxiing, it was discovered that fuel was coming
out of the fuselage on my Europa XS trigear (LN-ABM), through the access
holes below the tank. Draining of the tank was started and the leakage
stopped when 20 - 25 litres were remaining in the tank.
Two days before I had drained the tank completely since the aircraft had
been stationary (in a heated hangar) since 1. july 2006 with app. 35
litres of mogas in the tank. The day of start up I filled 18 litres and
checked all hose connections. Started the engine and runned it for 5
minutes to check hose connections to the recently installed oil
thermostat. Then filled another 36 litres of mogas and started the
engine for the local flight.
Removing the wings, it was revealed that the tank front facing the wing
spars, had great bulges, bulges inwards and outwards, and the centre
one touching the aileron cross tube, see attached picture. I have not
yet localized the crack, but I suspect the saddle section just ahead of
the fibreglass bracket. To me the in and out shape of the bulges
indicate compression stresses due to material expansion (caused by the
fuel applied, 95 octane mogas?). And I think the crack is caused by
shear stresses just forward of the bracket mentioned.
I will appreciate comments and advice. At present I do not trust the
material, polyethylene, used in the tank. Has anybody applied metal
tanks?
Regards
Arnold Kr. Hansen
Europa XS trigear, Kit No.381
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