Propulsion Definition and 291 Threads

Propulsion is the action or process of pushing or pulling to drive an object forward. The term is derived from two Latin words: pro, meaning before or forward; and pellere, meaning to drive.
A propulsion system consists of a source of mechanical power, and a propulsor (means of converting this power into propulsive force).
A technological system uses an engine or motor as the power source (commonly called a powerplant), and wheels and axles, propellers, or a propulsive nozzle to generate the force. Components such as clutches or gearboxes may be needed to connect the motor to axles, wheels, or propellers.
Biological propulsion systems use an animal's muscles as the power source, and limbs such as wings, fins or legs as the propulsors.
A technological/biological system may use human, or trained animal, muscular work to power a mechanical device.

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  1. T

    Is Boeing's Anti-Gravity Propulsion Project More Than Science Fiction?

    BBC NEWS: Boeing tries to defy gravity "The project is being run by the top-secret Phantom Works in Seattle, the part of the company which handles Boeing's most sensitive programmes." I think this article is a cover story/ program. They may already have anti-gravity figured out and of...
  2. E

    Swimming Freestyle: Propulsion Force & Drag Resistance

    :rolleyes: Recently I have gained great interst on understanding how I gain speed and move through water while swimming in a race. Using the Freestyle as example I have my body in the water creating drag forces or a form of friction. And I must use my hands and feet(mostly hands/arms) to create...
  3. H

    Fusion in a Coffee Cup: Can It Lead To New Propulsion?

    Hi I was reading an article in the New Scientist, about how fusion can be created in a device no bigger than a coffee cup. It said that an electrically polarised piece of deuterium doped lithium tantilate (don't know if this is the right spelling) placed in a strong electomagnetic field...
  4. R

    Is Attraction Propulsion the Key to Interstellar Travel?

    I am an amateur writer, and I do not have much more than a basic knowledge of physics. I am however, attempting to write a book centered around a new propulsion system and a trip out of our solar system. I will give everyone reading this a basic idea of the system, then I hope to read feedback...
  5. H

    Magnetic Propulsion in Salt Water

    Could someone direct me to research on using magnetic fields to move salt water through a nozzle for slow propulsion in salt water.
  6. D

    Solve Propulsion Problem: Rocket Mass, Fuel, Velocity, Altitude

    I was doing some problems from my problem book and got stuck at this one: A rocket of mass M has "fuel and oxidizers" inside it worth 'm' kgs . When propelling the exhaust gases have a constant speed of 'v' and the GASES are emitted at a constant rate of N kg/sec .Neglecting the air...
  7. D

    Anterior Propulsion: Lunar & Solar Forces, UCI Halt

    Need Further About Lunar And Solar Dynamic Force On Anterior Propulsion,, Stopped @uci , No Ferther Info Avail?
  8. S

    Model Rocket Propulsion: The Power of Hydrogen and Oxygen Combustion

    If say hydrogen is ejected out of the tail of a model rocket and combusted with O2 of the surrounding air, will that propel the model rocket forward and will the propulsion be sustainable?
  9. R

    Are There String Theory-Based Methods for Achieving Faster-Than-Light Travel?

    You are all probably familiar with the theoretical work of Alcubierre, Krasnikov, Thorne etc in the field of Wormholes and warp drives. Anyone know of any string theory based FTL drives?
  10. T

    Space propulsion lecture questions.

    Today I attended a lecture by guest speaker Dr. Terry Kammash. He was speaking about the possibilities of space propulsion, and fusion was mentioned. As fusion is one of the subjects that interestes me the most, I was eager to hear about it. However, he seemed to treat fusion as though we are...
  11. S

    Test rig to demonstrate propulsion

    hi all, i need to construct a test rig to demostrate propulsion, the rig need sto be onstructed according to factors that affect thrust any ideas how to go abt doing it? stan
  12. S

    Microwave Propulsion for Spacecraft: Exploring its Potential and Limitations

    If I had a Microwave oven (minus the door), and I placed this at the back of a craft that was already in orbit, if I activated the Magntron, could this propel the craft? Stupid question I know, but if it can be a source of propulsion, what would be the maximum or minimum craft to microwave...
  13. Mk

    Can a Simple Copper Coil Device Provide Efficient EM Propulsion?

    Any ideas for an easy cheap EM propulsion device? Is a homopolar generator the same thing as a homopolar motor?
  14. E

    Interstellar propulsion island hopping the Oort cloud

    Ahad's virtual bridge might have to charge a toll fee: http://www.astroscience.org/abdul-ahad/firstarktoalphacentauri/interstellar-propulsion.htm :!)
  15. S

    Top Jet Propulsion Books for Gas Turbines and Jet Propulsion

    Does anyone know of some decent books for Gas Turbines/ Jet Propulsion? Thanks
  16. U

    Rocket Velocity and Mass Ratio

    A large rocket with an exhaust speed of v=3000m/s develops a thrust of 24 million Newton. a. How much mass is being blasted out of the rocket exhaust per second and b. what is the max speed the rocket can attain if it starts from rest in a force-free environment with v=3000m/s and if 90% of...
  17. wasteofo2

    New method of propulsion, or simple BS?

    Someone on a guitar forum posted a link to this site, which supposedly outlines a new method of propulsion. I'm in high school and I haven't even taken physics yet, so I really am in no position to debunk this, but generally sites that look like that are just nonsense. So, does anyone who...
  18. A

    Which is the best space propulsion method?

    Wikipedia has an excellent article on space propulsion. Let us assume that less expensive cargo costs will create a demand for space transportation due to raw materials/energy/unique conditions in space. Similar to when earlier railroads created their own demand when they lowered transportation...
  19. P

    Magneto-Hydro-Dynamis Propulsion

    This is my first post on this forum, but i have browsed through this website a bit and found it very interesting so i thought i'd post a new thread... so here goes: Can someone please explain how MHD Propulsion works. I saw a little bit of a show about this on the Science channel...
  20. W

    Which is Better: Single Engine w/5 Gears or 5 Engines w/'Fixed' Propulsion?

    A single Engine with five gears, or five separate Engines with 'fixed' propulsion's, as opposed to transitional gearings? A rocket leaving Earth has 'boosters', once it is orbiting it uses propulsion systems that are more compact and have a weight-to-ratio output more efficient than Earthbound...
  21. K

    Could Electromagnetic Propulsion Revolutionize Space Travel?

    Im just wondering what you guys think of electromagnetic propulsion via asymmetric capacitors and high-voltage. If you've heard of it, what are your ideas on it? Do you believe it is ion propulsion or something else? There are also the additional components of the Lorentz force when derived...
  22. Clausius2

    Solving Propulsion Enigmas in Classical Physics

    I have some doubts waken up by one of the last threads in the Classical physics forum. Before anything, please open the attached file below. It is opened with word. Please assume subsonic flow in every picture. Cases a) and b): P<Pa. To where does it move?. You can see I have re-scaled...
  23. J

    How Can I Build a Small Electromagnetic Train for a Model Setup?

    Ok , here's the deal , i would like to build a small electromagnetic train ... ( not really a train , but you know what i mean... no bigger than an "N" scale train , if you know anything about model trains) i just want a basic simple setup that goes in a circle ... no bigger than a dinner plate...
  24. D

    SCR Propulsion Systems: Electric Motor & Towboat Power

    Anybody know anything about SCR...can an electric motor power a towboat with batteries and back up generator power say 1800 hp.
  25. S

    How to design a dolphin propulsion swimsuit?

    I'm not an engineer, but I want to design this all for my self. So I have a few questions, for the bright out there. :-) [excuse me for my bad english, I'm not a native speaker]. I want to design a swimsuit (more a lightweight aerodynamic "rack" which you strap yourself into) which has a...
  26. S

    Rocket Propulsion, Newton's second law

    I was reading a section about rocket propulsion in my general physics text and it came up with the following formula: m \frac{dv}{dt} = - v_{ex} \frac{dm}{dt} I don't have much trouble with this formula, but then it went ahead and substituted m dv/dt as the thrust experianced by the...
  27. C

    Magneto Hydrodynamic Propulsion for hypersonic aircraft?

    I watched a "Black Aircraft" show on the science channel. In the show they mentioned a researcher working on old Russian technology that placed a strong beam in front of the aircraft to strip electrons from the air molecules so the plasma creates its own initial shockwave to lessen drag on...
  28. S

    Picking a Science Topic: Balancing Nanotech, Ion Propulsion & Forensics

    I am doing a high level three year course in which I pick a science topic and do research on it. I will have the privilege of working with scientists and professors from several universities and laboratories and for this course I get 12 college credits, plus one high school credit for each of...
  29. I

    Electric Field Propulsion for Starting a Gas Engine?

    My mind was wandering the other day in class, just after our physics teacher showed us the railgun he and his class made a while back. Anyway, I was wonder if you could use this principle in starting a gasoline engine. If you wrapped the electromagnetic coil around a cylinder, and fired it...
  30. R

    What Are the Implications of Reaction Torque Propulsion?

    What do you think of this web page? Reaction torque propulsion It challenges some important notions.
  31. S

    Relativistic Mass Propulsion or the RMP

    Plates spinning when they move down and are still when they move up; the plates would have higher mass when moving down then moving up. Should work.
  32. S

    Microwave Propulsion: Using RF to Push Magnetic Fields

    I once asked a JPL engineer if radio energy could affect a magnetic field, his answer was just plain no. But I have a problem with microwave RF affecting bipolar molecules. I mean microwaves cause these molecules to vibrate and they do so because the RF affects the electric and magnetic fields...
  33. S

    Could Magnetic Circulation Be the Key to Propelling Spacecraft?

    Hello, Thanks in advance. I have an idea. But I know nothing in this field. Is it possible to use a revolving mechanized magnet to change the force of gravity? My idea: If it were possible to use magnetics to circulate a material to a speed soo fast that it could influence the...
  34. L

    Candidates for near-future nuclear propulsion systems

    Times are changing, what with the renewing of space exploration. Humanity should be un-arse-ing itself and moving towards our celestial neighbours. But we will only go to them, if we harness a better power souce. That, my friends, is good old nuclear propulsion. And yet, there are so many...
  35. P

    Boosting Speed with Rocket Propulsion & Momentum

    rocket propulsion/momentum A 1520 kg rocket has 4860 kg of fuel on board. The rocket is coasting through space at 94 m/s and needs to boost its speed to 348 m/s. It does this by firing its engines and ejecting fuel at a relative speed of 807 m/s until the desired speed is reached. How much fuel...
  36. S

    Questioning logic used for highschool rocket propulsion problem

    Standard rocket propulsion problem. We are supposed to derive an expression for the final velocity of a rocket being launched into space based upon the exhuast velocity (Ve), final mass (Mf), intial mass (Mo), g, and time. The only forces acting on the rocket throughout the motion is the force...
  37. L

    Calculating Rocket Height with Changing Mass: Guide & Tips

    How do you go about finding the height reached by a rocket with a changing rocket mass if you know the specific impulse, the mass ratio (original mass/final mass) and the thrust to weight ratio? Any help you can give is greatly appreciated. edit: I would show you my work on this problem but...
  38. J

    Exploring Nuclear Pulsed Propulsion

    hi there I am a middle school student who just recently read "Visions". I became very interested in nuclear pulsed propulsion and am considering doing some type of deonstration for my school science fair. (I also do 3d computer modeling and animation) 3 questions 1- is there any good...
  39. H

    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
  40. wolram

    Latest theories are for inter stellar propulsion

    can anyone tell me what the latest theories are for inter stellar propulsion, and has the problem of bone loss on long space flights been solved?
  41. B

    How Do Maglev and Inductrack Trains Operate?

    Hi All, I am looking into Maglev, and Inductatrac trains. I thought that an in depth study of how they work, the pros and cons of them would make a good science fair project. First of all do u guys know any websites i could find to look more into this, and any ideas for possible...
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