LNG Powered Plane

LNG powered plane requires considerable design changes to a traditional plane such as placement of the fuel tank at the back of the plane and removal of engines under the wings. These changes require structural redesign of the plane.

The lack of fuel and heavy engines on a wing would make them lighter while they wouldn’t need to support those weights. Removal of previous design restrictions on the wings would allow aerodynamically more efficient wings to be designed. The shift of the center of gravity of the plane would also shift the position of the wings. The removal of the engines under the wings would enable them to be placed closer to ground. This also reduces the height of the landing gears.

The passenger cabin of the plane would be limited to the front of the plane. The emergency exits should be placed accordingly. The placement of the engine at the back of the plane would make the cabin much more silent even at its back. The engine would be separated from the cabin by a cryogenic tank and the exhaust gasses would be emitted at the very end of the plane. Considerable amount of reduction in noise would negate the need for noise reduction materials inside the fuselage.

The plane would utilize the vertical turbofan engine I proposed earlier. This design allows independent centrifugal compressors for redundancy which would be powered by the expansion of the liquified LNG. LNG expands almost 600 times when gasified from liquid. This would result in fuel efficiency while classical turbofans consume fuel to compress the air. The expansion pressure of the LNG also negates the need for complex fuel pumps used for jet fuels. The high-pressure fuel injectors would also be replaced with much simpler injectors while the fuel is already in the high-pressure gas form. The plane would have a single large engine generating thrust in line with the direction of motion. The compressors and the combustion units would be multiple for redundancy. A single thrust source allows easy control of the plane even when some of the units fail. On the other hand, classical planes with multiple engines are harder to control in case of engine failure.

Finally, vertical engine I propose requires no gas turbines to power the compressors which require cooler exhaust gasses to operate. As a result, my engine can have a much hotter exhaust gas with higher velocity and therefore better fuel efficiency. Additionally, LNG has much less carbon emission compared to jet fuel. There are a lot of design changes required for an LNG plane. However, once the design is established it wouldn't be more expensive to build an LNG plane compared to the classical ones.