I only ask this 'cos, after doing a lot of flying recently I've become slightly fascinated by how jet airliners work.
Now… when taxi-ing on the tarmac they appear to be able to move (and even partially steer!) using their jet engines, but can only go in a forwards direction to do this – and hence the need for one of those funny little car things to initially 'shunt' them out onto the taxi-way.
But… when walking onto the plane – I'm always aware of some secondary jet engine running somewhere – that is definitely not wing-mounted. I can hear and smell engines running, even though the wing-mounted jet engines are stationary. Infact – an engine somewhere appears to be exhausting from that strange 'anus' 🙂 on the tail of the plane – what is this? It there some sort of secondary internal jet engine inside the plane, somewhere, that provides power (electricity) for while we're sitting stationary on the tarmac..?
So… is power from this engine used to 'start' the main engines on the wings? … if so, how? …And what else is this internal engine used for?
Or have I got this all wrong..?
I could go on and on.. but I'll stop there. I think I may have become a little bit obsessed with all this 😛