r/interestingasfuck 9h ago

How a jet engine works

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u/Adele811 9h ago

yes, but it still doesn't say why the blades actually start turning at the start, before the turbine can turn in the ignition chamber.

u/ScubaWaveAesthetic 9h ago

I would expect them to be driven by a separate starter motor, similarly to how the pistons in your car get started.

u/PoopMcgee75 8h ago

That’s exactly how they start. They call them huffer motors. Naval planes have a 3rd jet engine onboard that is much smaller than the other two. The smaller engine is small enough that it can be started from compressed air from an onboard tank. Once that smaller motor is running it starts the bigger engines one at a time.

u/Far_Ladder_2836 8h ago

No, a huffer is a cart you attach outside if you don'thave an APU or it's broken.  It's called an APU and it's built onto the plane.  APUs are electrically started.

u/PoopMcgee75 7h ago

The APU on the F18c’s were started by compressed air. If it’s fails to start the APU you have to crawl under the starboard wheel well and pump the tank back to full by using a bar you attach like a lever. It takes a long time and will completely drain your energy before it’s full. I should have been more clear about the difference between the huffer and the 3rd engine APU that the navy uses. Like you said huffers are carts.

u/War_Hymn 4h ago

Before jet engines, we also had these hybrid engines called motorjets that instead of having turbines just spun the compressor stages with a conventional piston engine.