Jet engine terms?

Question

what does it mean when it says the jet engine gets lets say 17 lb thrust at whatever rpm's. does that mean it can only lift 17 lbs? so if i wanted to lift something weighing 50 lbs into the air i would need 3 jet engines?

thanks

Answer 1

The 'thrust' generated by a jet engine is the quantity of air which is produced from the exhaust, which in turn pushes the aircraft forward. This is expressed in lbs. Thrust shows the power of the jet engine and has nothing to do with the lifting capacity of the aircraft (which depends of the wing section). Thrust merely propels the aircraft through the air while the wings generate the lift.

Answer 2

Theoretically yes. If you point an airplane straight up and it has more thrust than it weighs it will climb. Called thrust/weight ratio. A Harrier hovering is producing exactly the same thrust in lbs. as the aircraft weight. And no, lift is not 100% generated by the wings. If that were true, how does an airplane fly on knife edge? And folks, a saturn V rocket has many pounds of thrust and no wings. Hmmmmm. Were talking engine power here folks, not aerodynamics. He wants to know if thrust can lift things. You bet it can. No wings required.

Answer 3

lbs of thrust is a measure of the engine's pushing power. so in your case, if you stand behind a 17lbs producing engine, you would feel 17lbs pushing on you.

it does not determine lift.only the max speed and acceleration.

engines are used to push or pull the aircraft forward so that the air flowing over and under the wings can allow the wings to create lift.

lift is 100% generated by the wings

PS: lbs of thrust is not determined by taking the quantity of air coming out of the engine and weighing it as ayesha claims. engine's do not produce air.

jet engines merely cause a controlled explosion by mixed air and fuel and igniting it and then channeling the resulting explosion towards the rear in order to push something forward.

here is an example of the thrust produced by a 747's jet engines, which is in excess of 240,000 lbs total.

http://youtube.com/watch?v=rtywDrpn6ws

Answer 4

Most of the lift is is a force from the wings, not from the engines.