Im more of a person sensitive to pollution and putting green house gasses in the atmosphere. So I had a plan for a jet engine to use methane, Was going to use methane gas for my first prototype to see how well methane ignites. Then I was going to move on to liquid methane. Advantages of methane is its light but at the same time denser than kerosene and lighter. Disadvantages is the ignition needs to be very hot, Not plasma hot. But something that needs a spark to ignite it.
Was going to focus on a small jet engine. Around 2 pounds of thrust, And around 600 grams of fuel(A gallon of liquid methane because its lighter) The estimate for how much fuel it will use is around 600 secs every gallon. So ten minutes is the flight time at full throttle. Thrust ill be about 2:1 thrust to weight ratio.