That's a great goal to have! But if you're putting energy into a flow using a propeller or fan, aerodynamic stall means that each propeller can only put a limi

That's a great goal to have! But if you're putting energy into a flow using a propeller or fan, aerodynamic stall means that each propeller can only put a limited amount of energy in. This is why jet engines have so many compressor stages - each one adds as much energy as it can without stalling out: https://en.wikipedia.org/wiki/Gas_turbine#/media/File:J85_ge_17a_turbojet_engine.jpg https://en.wikipedia.org/wiki/Gas_turbine#/media/File:J85_ge... In the engine pictured, which has 8 compressors in a row, the energy which those fans are able to put into the flow is miniscule compared to the energy that you can dump in by burning fuel (or electricity) in the tiny combustion chamber. F-16 in afterburner is consuming 64,000 pounds of fuel per hour = 18 pounds per second A pound of Jet-A has 20 MJ per pound. So that's 360 MW of thermal power. Even if you're only turning 10% of that into usable thrust, that's 36MW of power. Here's what a 35MW power plant looks like: http://www.power-technology.com/projects/ctds_chp/ctds_chp5.html http://www.power-technology.com/projects/ctds_chp/ctds_chp5.... The people working on electric jets are well aware of the Carnot limit, and it's true that they don't want that. But for now, we'd need a lot of new tech to put 35MW of thrust power into a flow using electric motors and fans. Heck, we need a lot of new tech to put 350MW of power electronics onto an airplane!! My only point is that I don't think we should look down our noses at the people working on thermodynamic machinery. Until we can do better, they're the best we've got :)