Originally Posted by
james ozzie
We all once sat in a classroom and learned that a rocket engine is a reaction motor, relying on the reaction of expelled exhaust mass to create an opposite reaction force (Newton 2). We also learned that a turbine creates thrust in exactly the same way (reaction from exhaust action). Simple.
We then sat in another classroom, learning about propellors and helo rotors. These things use rhos, vee squareds and angles of attack to create lift and thus "pull" the aircraft forward/upwards. Great.
Then along came high bypass turbofans - ah, still a reaction motor. Then someone took the bypass ducting off - so is it a prop or a reaction motor....? How do those air molecules know which equations to follow? (obviously, they follow both)
Is it not so that all of these should be regarded as reaction motors, with a propellor just being a type of unducted fan?
Sorry, this may be an old chestnut? Simple comment from the propulsion experts out there would be appreciated. Thanks
Turbine or piston, jet, fan or prop; the idea is still the same: you move air one way, you go the other. It's just a matter of how to move the air, and that portion I think you already know. Sometimes things get harder the more we think about them
