# What is Jet propulsion: Definition and 12 Discussions

Jet propulsion is the propulsion of an object in one direction, produced by ejecting a jet of fluid in the opposite direction. By Newton's third law, the moving body is propelled in the opposite direction to the jet. Reaction engines operating on the principle of jet propulsion include the jet engine used for aircraft propulsion, the pump-jet used for marine propulsion, and the rocket engine and plasma thruster used for spacecraft propulsion. Biological systems include the propulsion mechanisms of certain marine animals such as cephalopods, sea hares, arthropods, and fish.

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1. ### B Could Jet Engines Be Used for Space Travel?

Here's a really complex & difficult question... Satellites orbit Earth in the upper thermosphere. Could a jet engine (not a rocket) produce enough thrust to move a small craft? The reason I'm asking is because it most certainly would produce "some" thrust in low orbit. The atmosphere extends...
2. ### Rocket Specific Impulse vs Jet Engine Specific Impulse

I really can't seem to wrap my head around why the specific impulse on a rocket is so much lower than that on a jet. I know a jet engine has a larger supply of oxygen, but I don't see why that has such a huge effect. I also know exhaust velocity plays a large part, but I would have thought that...
3. ### Good books on propulsion systems?

Any recommendations for books on Propulsion Systems that arent \$100+?
4. ### Answer: Energy of Rocket in Uniform Gravity Field

Homework Statement How does change the total energy of the rocket during its motion inin a uniform gravitational field? 2. The attempt at a solution My idea is to write the law of conservation of energy systems - "rocket- gases" ##\frac{dE_{total}}{dt}=0## But get very cumbersome terms , the...
5. ### Velocity and mass relation by fluid jet propulsion of a squid

Several species, including the squid, cuttleﬁsh, dragonﬂy ﬁsh and many microscopic organisms, move themselves around by a kind of jet propulsion. In each case the animal absorbs ﬂuid in a body cavity and expels it through an oriﬁce by contracting the cavity. If a squid has a mass Ms when its...
6. ### Exploring Jet Propulsion: Building a Replica Model of a Hero's Engine

hi Im currently studying aeronautical engineering at college and needed some ideas for projects and whether they would be pliable or not My current idea: A replica of hero's engine to show the basic principles of jet propulsion but to spice the idea up a little bit, i was thinking about...
7. ### Jet vs. Wheel Efficiency: Which is More Effective for Land-Based Vehicles?

Let's suppose one wanted to move a wheeled, land-based vehicle. Generally, which would be more efficient, and why? Using a jet of air straight out the back (like the Batmobile seen in the 1989 Batman movie) or absorbing most of jet's thrust through a turbine and delivering that force to the...
8. ### Jet Propulsion Career Advice: Best Route & Top Colleges in Plymouth, UK

Hi, my mate has just left school and wants a career in jet propulsion or aircraft structure, he lives in plymouth (uk) and don't have any A to C grades... what would you recommend his best route is? and what decent colleges are there that specialize in this sort of thing?
9. ### Pulse jets and ram jets as part of my course on jet propulsion

i was reading about pulse jets and ram jets as part of my course on jet propulsion. all i was told was that they are aero-thermo-dynamic-ducts. couldn't understand what they mean. checked google, but the articles i got were vague. could someone explain what aero-thermo-dynamic-ducts are?
10. ### Question about jet propulsion.

In the general thrust equation in order for a jet engine, either turbojet, ramjet, or scramjet, to produce net thrust the speed of the exiting exhaust has to be greater than the incoming speed of the air flow. Then the net thrust is the mass exhaust rate times exhaust speed minus the air mass...
11. ### Top Jet Propulsion Books for Gas Turbines and Jet Propulsion

Does anyone know of some decent books for Gas Turbines/ Jet Propulsion? Thanks
12. ### Current theorys in fluid dynamics for jet propulsion

anyone know any theories being used for fluid dynamics? any formulas? I aint no physicist, I am just curious. Are there any developments today involving jet propulsion by going faster with only half the fuel? if that sounds right. any help would be appreciated