Do a jet engine’s turbines actively pull air into the engine once the turbines begin to spin? (Both during the starter motor phase and also during flight at higher speeds)
And does the front half of the engine produce a substantial amount of drag as it is travelling at high speeds? (not including the thrust coming from the back)
If anyone could help it would be much appreciated!
*I’m thinking about axial and turbofan jet engines, but am curious about all types, *apart from pulse jets*
Cheers!
In: 3
Aircraft mechanic here:
Drag: The engine sucks air from the front, faster than the air is hitting it, let’s say. So it’s not making drag, it’s actually pulling itself forward like a propeller. What makes drag is the nacelle but you can’t really do otherwise. The nacelle is basically the best way to cover the engine, protect the engine and streamline the airflow to the engine and around it. Technically we can say it’s drag, but it’s drag you can’t do without. If you shut down an engine in flight, the entire thing will make some drag, not little, not the end of the world.
Pulling air: yes, it pulls water, tarmac, rabbits, bolts, shoes, people, and whatever you leave on the floor into it. Definitely sucking stuff.
Turbines: no, the turbine is a windmill that is moved by the hot gases provided by the combustion chamber. The combustion chamber is a glorified kerosene stove. The compressor is the one that sucks the air. The Fan is the first stage of the compressor in a turbofan and does suck a lot of air. A fraction of the fan air will then get sucked into the next compressor stages while a lot of this air is just shot out of the back of the engine and it’s what gives you a big chunk of the engine thrust.
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