[quote=Edchris177]PS
Andrew, the old joke of suck,squeeze, bang, blow, is just that, a joke to describe a 4 stroke internal combustion engine. Everyone understands that air enters on the intake stroke as a result of atmospheric pressure, not suction, & that to restore power lost at altitude (due to decrease in atmospheric pressure)we use turbo charging or super charging, "a blower" to create more pressure on the intake side.
The jet engine also uses the same four cycles, they just occur continuously & simultaneously. Compression is achieved aerodynamically through acceleration then diffusion at each stage through the turbine, a stage consisting of a rotor & stator disc. I operate the most powerful turbine engine in commercial production, the GE 90-115B, output 115,000lb of thrust. I would not agree with the poster who said they "suck, squeeze,bang,blow, with less moving parts. Compression alone is 13 stages,(appx 45:1)& each stage has a hell of a lot of blades. Add in the fan, thrust reversers etc & your parts count is getting up there. The front fan of a modern jet engine is a glorified propellor, & is shaft driven by the low pressure turbine. This fan moves a large volumn of air backwards at a relatively slow speed, utilising Newtons law of action/reaction. The "propellor" also uses the high pressure on the back side of the blades to push the aircraft forward, it does not get sucked forward, ditto for the rotating blades of a helicopter.
Ask your GF for Mechanics of Flight for your birthday, you will find many days of enjoyable & educational reading :-)<!-- editby --><em>Edited by Edchris177 on Dec 31, 2010 - 11:14 PM.</em><!-- end editby --> [/quote]
