Build a cheap turbofan
From NPrize
How to build a cheap (~ $150) turbofan?
Turbofan advantages over other propelling ways is that they provide enough trust to climb at high altitude, possibly at attractive speed, and that they are not much fuel-greedy and thus can be running for some time with limited extra-weight.
General principes
Turbofan blades are made of nickel-based superalloys.