Another factor to consider in the fuel-tank-in-the-cabin issue is whether putting it ELSEwhere might increase the potential for an accident.

A Fly Baby might be a good example. Putting fuel tanks in the wings would be the only other option. But splitting one tank into two means the pilot now has the opportunity to mismanage the fuel valve and run one tank dry at the wrong moment. Putting the tanks in the low wings means that the airplane needs a fuel pump to get the gas to the engine. Another potential failure point.

Remember, the P-51 had a fuel tank right behind the pilot...

Ron Wanttaja