Item 0189

MAKE: Fuel - Tank - Low Location

Drawing:

 

 

Notes:

Low Location will necessitate fuel pump(s).

Consider 2 tanks at 2.5 gallons?

 ‘Polyesters have a lower moisture absorption and high chemical resistance which makes them well suited for fuel tanks.’

Does this mean that an epoxy fuel tank as part of the structural body may be a problem? Can inside of tank be coated, if necessary?

 April 28, 1999

Idea: Consider having 1 or 2 fuel tanks that are not composite but attached and sit on a part of the composite body. These tanks could/should be removable for inspection and adjustment of other components. If the tanks are removable then they can have a "tighter fit" around the power train frame since they can be removed before removal of the power train assy.

Consider using Eipper 5 gallon molded fuel tank. On the Gyrobee it is held on by a bungee chord and can be dismounted if it has to be used as a gas can for refueling

Mount fuel tank high behind seat with gravity feed to engines. Potential problems:
    1. Leakage of fuel onto hot engine, particularly in a crash.
    2. Tanks will block some of the cooling air to the engines. Unless it has a pyramid shape and the base dimensions coincide with the frame.

Have 2 fuel tanks, one each side. One for each engine, or 2 tanks feeding a single engine. This will give a balanced load plus the safety of redundancy.

Or put fuel tank(s) under seat so that its collapse will help absorb shock of emergency landing. ~or~ Put reserve portable tank under seat which can be used to refill main tank and also serve as compressible safety device.

Consider safe means of draining tank(s) to lighten load for emergency landing. Make sure tanks will not drain by them selves. Perhaps pulling flexible hose to engine will siphon off gas

Fuel tank(s) could be part of power train instead of part of fuselage.

Consider internal baffle(s) to control the effects of sloshing.

Consider lining the tanks with a crash resistant flexible blader.

Fuel Reserve (Safety)

1/ The fuel arrangement must be such that if one engine runs out of fuel there is still enough in the other for semi-autorotation and powered flare.

2/ An idea, for a fuel pump system only, would be to have a small 'bottle' located after the pump and in the fuel line to 1 engine ONLY. This bottle would be in an inverted position and located after a check valve. Should the main fuel tank go dry, then this one engine will stop say 30 seconds after the first because it was still receiving fuel from the pressurized bottle. The pressure would come from the air trapped in the inverted bottle. The 30 seconds would allow the pilot to setup for autorotation.

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Last Revised: June 16, 2000