mrkmg t1_iroxar6 wrote on October 9, 2022 at 10:30 PM

Reply to comment by InevitableRip8968 in TIL that passenger jet engines produce most of their thrust from fan at the front, not from the jet exhaust, and that this is called a high-bypass engine. by Rilot

Well... The ratio does shift slightly, but not enough for the jet thrust overtake the fan.

But really I wanted to add:

Performance =/= efficiency. If you take the entire system (the thrust, fuel consumption, drag, etc) there is an ideal altitude that's really high up where the whole aircraft is most fuel efficient.

This stuff is so complicated that they use entire farms of servers to calculate expected performance and efficiency of aircraft designs.

InevitableRip8968 t1_irp38q4 wrote on October 9, 2022 at 11:16 PM

Can you show me proof? Bypass ratio always stays the same. This is taking in to factor if you ignore bypass ducts that newer engines use.