Liquid Hydrogen as an Aviation Fuel Fossil fuels are getting exhausted paving way for an energy crisis. So an alternate fuel that is a beneficiary and relevant substitute for the present day fuel are to be acknowledged. One such fuel is liquid hydrogen. . A very supportive study of various considerations and modification of different aircraft technologies that incorporate this new generation fuel is made. Liquid hydrogen is a safe fuel as they are less susceptible to damage. These along with many other advantageous reasons add up for the convenient common usage of liquid hydrogen An ordinary turbo jet engine can be modified to work on LH2.LH2 was supplied to the engine by a single stage, engine driven by a centrifugal pump, which is operated with a slight net positive suction head to prevent cavitations prior to injection into the combustion chamber, the LH2 was passed through a counter flow heat exchanger where it was warmed by air bed from the compressor discharge. An axial, tube type injection used, which is as short as about one fourth the length of those required for conventional hydro carbon fuels. The hydrogen is pumped to 600 psi and while passing through heat exchanger it was heated to about 1800F. The hot hydrogen gas was then expanded through 18 turbine stages, which were divided into two sections of 6 and 12 stages each, arranged so as to balance the thrust loads. Hydrogen gas from the turbine exhaust passed through injectors into an annular combustion chamber where it is mixed with air discharged from the fan and burned at about 2000F. The combustion gases then flows through the heat exchanger to provide the energy required by the hydrogen to drive the turbine. Excess hydrogen, not burned upstream of the heat exchanger was bypassed to an afterburner just downstream of heat exchanger. A convergent divergent nozzle completes the Model 304 Engine Cycle. The figure shows Model 304 developed by Pratt and Whitney Aircraft division of United Aircraft Corporation