LSAs with a single fuel tank in the fuselage

[snaproll]

I'm onboard with snaproll's thesis, with some qualifications. The tank has to be engineered right, and it has to be defect-free. The fuel shut-off, sight gauge (if present), the breather, and the fill cap are all included. With that in mind, I think the fuselage tank could be safer than wing tanks, especially wet wings. That is because the tank in the fuselage can be easily made inside the survival cell, while wings are made to be sacrificed with the resulting rupture. The alternative is Diamond's two-longeron wing.

For what it's worth, in the 2nd fatal of Remos the airplane broke up at impact, but there was no fuel tank rupture.

Thanks Pete.. Besides pilot error, Remos' main problem has been failure to preflight and verify controls are engaged properly (especially for the guys who fold their wings). I agree with your above qualifications on fuel systems. When I used to design and build a tank, it was always tested to 5 PSI using a column of water - VR.. Don

[Jim Stewart]

I'm much more concerned that I can exit the aircraft if it's inverted. That's why I like my high wing.

[MrMorden]

When I was at the Sonex builders' workshop, this came up (Sonex fuel is between the firewall and the panel, over pilot's legs). Their reasoning is that:

1) In a crash, a pilot's natural reaction is to avoid hitting anything directly with the fuselage, and to steer the fuselage between obstacles like trees where possible.

2) Because of (1) above, wings are often the first thing to receive catastrophic damage, making wing tanks more likely to be ruptured in collisions.

3) The end result is a wash. If the fuel tank in the fuselage is split, the results are more likely catastrophic, but the chances of that outcome should actually be less than with wing tanks.

4) Build fuel tanks as strongly as possible wherever you put them.

This convinced me, and has worked for the Sonex. They have a very strong roto-molded polyethylene fuel tank -- I only know of one post-crash fire in a Sonex, the result of a nose-first stall/spin onto the runway that completely destroyed the aircraft and killed the pilot before the fire ever started.

I would look at each airframe type individually; I think overall construction and thoughtful design of the fuel system is far more important than where the tanks are located.