What is Propulsion: Definition and 290 Discussions

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.

View More On Wikipedia.org
Recent contents Top users
  1. Y

    I Interstellar Travel Without Propulsion or Time Dilation

    I hope this is the right forum for this question. Imagine alien tech allows them to travel 1 million light years to Earth instantaneously. No thrust, vector, propulsion was involved. They didn't have to approach the speed of light, with its attendant increase in mass. Having arrived at earth, in...
  2. P

    I Is it possible to use the vacuum to launch a rocket?

    Hey I'm new to Physics. I have a question. Is it possible to use the force generated when air entera a vacuum tube to launch something into space? Can anybody throw some light on this in simple words please. Thank You.
  3. JTC

    Exploring Centrifugal Propulsion: Demystifying the Mechanics and Misconceptions

    Hi I am spending time on youtube looking at videos that come up when I search "Centrifugal propulsion" (No need for me to pick a few, you can do a search and see lots.) Most of the videos look poorly made. All show some sort of "vehicle." But the "vehicle" jitters back and forth. I am...
  4. scott ketter

    I What do you think about gyroscopic propulsion? possible?

    I am just trying to get a feel for peoples opinions and supporting math/physics on the possibility of gyroscopic propulsion. Do you think it is possible? Why or why not.
  5. T

    Understanding Expansion Fans and Reflected Waves in Propulsion Systems

    "For simplicity, let us assume the flow turns around a corner downstream of the throat, where the Mach number is M0 > 1, to an angle θ1, and let us indicate just three of an infinite number of waves making up the "expansion fan". Since the centerline is an axis of symmetry, the waves must...
  6. ISamson

    The Future of Space Exploration

    Hello. As many theories and hypotheses that there are about a secure, reliable and effective future space exploration and colonisation that there are, I would like to dedicate this thread to the discussion of this topic. Some of the suggestions are: Von Neumann probes are an effective strategy...
  7. anorlunda

    KISS Principle Marine Propulsion

    I"m a big fan of the KISS principle in engineering. I'm also a boater. I just found something I wanted to share. It is a permanent magnet motor in which the propeller itself is the rotor. The video hints that it works with simple reversals of polarity similar to a stepper motor. That...
  8. A

    Courses Want to do spacecraft propulsion R&D but love astrophysics

    I've always been fascinated with space and space travel and want to see humanity advance in that area. I've always thought the best way for me to contribute is to work in research and development for propulsion systems (which I'm interested in), however, my main passion in physics is...
  9. ciao_potter

    Maximum Distance Traveled with Constant Propulsion

    Lets say that we have a rocket positioned at a certain angle with respect to the horizontal. The rocket is fired, with a constant propulsion force of . Assume that the rocket has a constant mass of kg (the gas used to propel the rocket is negligibly small). What is the optimal angle with...
  10. R

    Near solar mirror for beam propulsion and space solar power

    NASA just announced a solar probe to travel quite close to the Sun, about 3.7 million miles from the solar surface: Nasa’s hotly anticipated solar mission renamed to honour astrophysicist Eugene Parker. Renamed the Parker Solar Probe to honour solar astrophysicist who predicted high speed solar...
  11. R

    Light beam propulsion without lasers?

    We now have the capability to do laser launch. The problem is the initial cost outlay for the lasers is still prohibitive to launch a sizable payload. The estimate of the payload you can launch to Earth orbit dependent on laser power is about 1 kg per megawatt. So to launch thousand kilo...
  12. M

    The EM Drive: Exploring the Possibilities of Laser Propulsion

    I just had this thought while watching a video about the EM drive...basically using 2 lasers to bounce them off prisms inside an object to push the craft through space at a small but constant acceleration...could someone explain why this would not work?...please see attached image :)
  13. O

    Iron Man Flight Propulsion: Exploring NASA's Electric Propulsion Technologies

    How does Iron Man flight propulsion work? It seems to be pure electrical, there are no jet fuels involved. What devices presently being contemplated by NASA that can produce propulsion purely on electricity that doesn't rely on fuels?
  14. Buzz Bloom

    NASA NASA support for a "new" kind of propulsion

    I recall that a few years ago NASA awarded a contract for a "new" kind of propulsion, the details of which I have forgotten, and I would like to find any old news announcement about this from about the time of this award. My memory includes that the NASA contract to study this "new" method of...
  15. Xilus

    I Can Angular Momentum Create Forward Movement?

    OK so a trust can produce a torque, But two torques can't produce a thrust? There is no way to convert angular momentum into forward momentum.
  16. HyperTechno

    Arthur C Clarke's space ships -- propulsion discussion

    I've read Sir Arthur C Clerk's space odyssey series and curious of the propulsion technologies used in those ships. Ships like Universe and Galaxy of space odyssey 2061 use just water. The fiction speaks of "muon propulsion" too. The main spacecraft s that we see in his 'space odyssey' series...
  17. R

    Underwater Propulsion: Pumping Out Water for Acceleration

    Can water inside a submersible object be pumped outwards to provide an acceleration while underwater?
  18. A

    Formula to calculate amount of force needed to lift/hover

    I was thinking off building a drone and I was just curious about what the amount of thrust we need to be in order to hover based on weight
  19. schplade

    Beam-powered propulsion - keeping the beam focused

    I've often read that beam-powered propulsion is the only basic interstellar propulsion concept without physics problems. To me, that doesn't seem far from the truth. However, for a long time I've felt that the biggest obstacle to overcome is the beam divergence problem. Most of the concepts I've...
  20. S

    B Exploring Intergalactic Space Expansion Using Light Propulsion

    Hello all, Is electromagnetic radiation considered a driving factor of intergalactic space expansion similar to directed energy propulsion? I assume every point in space has countless photons passing through it from every direction at all times.
  21. Mr lee

    Magnus effect in flettner rotor

    Mr lee said: ↑ hi -new but enjoyed years, wit and wisdom Flettner rotor on a boat - ie. magnus effect Can the vertical rotor create lift? a curve balls 'laces' exaggerate and bend the magnus effect. can you replicate this effect on a rotor? --perhaps to enable another direction of force-- up...
  22. RandyD123

    Can light generate propulsion?

    If I put a flashlight in space, would it propel itself forward by "shooting out" light?
  23. Ivan Ramos

    Engineering Important career advice needed

    hello, I am currently a sophomore pursuing a bachelor's in chemical engineering at Auburn University, Alabama. While chemical engineering is a great career, I just do not think that it is for me and I feel like I will enjoy Aerospace engineering a lot more (i really, really like physics and am...
  24. U

    Propulsion by Cosmic Particle Deflection: A New Idea?

    What about the attached as a means of propulsion? It would be a spacecraft with a long magnet in the front. Attached on one side by boons the magnet would have a reflector/deflector or shield of some type e.g. aluminum. In interstellar space there would be charged cosmic particles moving in...
  25. L

    Theoretical Magnetic Propulsion

    I was curious to the effects of a strong electromagnetic field applied to an object at distance. The field must be able to quickly activate and deactivate in order to account for the distance traveled towards the object as to eliminate the force applied to the source of the field by the object...
  26. A

    What are the equations for fission-based spacecraft propulsion?

    Hello I'm working on a project to create spacecraft engines that use fission to produce thrust. I will be coming up with many equations and I wanted to have them checked. If you could review them and give me some feedback that would be great. Here is the first equation that describes how the...
  27. K

    Mechanical Space Propulsion. Why isn't this possible?

    So I've been told this is impossible before, and while I understand some of the reasoning as to why, I still can't wrap my head around how this wouldn't work, or rather, what it would do instead of working. So here's an image of what it looks like: Its function is this: Step 1: 'Forward'...
  28. F

    Newton's 3rd law & rocket propulsion (detailed explanation)

    I had someone ask me how rockets are able to accelerate in space and my initial answer was that the rocket fuel combusts and is heated into an energetic gas, the gas is accelerated out of the back of the rocket (i.e. the rocket exerts a force on the gas), then according to Newton's 3rd law, the...
  29. Borrah Campbell

    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...
  30. H

    Resonance Propulsion: Using EM Waves to Induce Movement

    Here's a weird idea: solid materials each have an inherent, but potentially modifiable mechanical resonance frequency. Step 1- energize the material mechanically by inducing vibration (ie. increasing the amplitude of occillations). Step 2- strike the material intermittently with an intense...
  31. C

    Uncovering the Secrets of Superman's Flight

    Hi, How does Superman fly? Does he emit gravitons or does he control the spacetime curvature since he doesn't have any jet or wind based propulsion system?
  32. D

    Rubber band propelled plane

    Hello PF! I have a project/competition in freshman college Aerospace that calls for a plane that can stay in the air for as long a time as possible while going as far as possible. The requirements don't explicitly say we need rubber bands as a propulsion but pretty much prohibit everything but...
  33. T

    Determining Launch Velocity to Overcome Drag (no propulsion)

    Hi everyone, I'm working on a project for my electromagnetics class which asks us to design an electrostatic launch system that can propel an object into space. Though the bulk of the project is supposed to be about designing the accelerator plate array, I got really interested in the whole...
  34. C

    Nanoscale propulsion system that works in vacuum - or not?

    Moved this question from the quantum physics section to this section, since... Well it fits this section better since electrons apparently do obey conservation of momentum in the 'classical' sense. Why not produce thrust in microgravity with electrons? Plenty of harnessable electricity in...
  35. onion3000

    Ramjet/Scramjet Propulsion on a Vertical Rocket?

    Is it possible (practical/efficient) to utilize ramjet (or scramjet) on a vertical rocket? By this I mean would it be at all practical to make a vertically traveling rocket which partially uses ramjet as a method of propulsion, or is there some property of ramjet propulsion that makes this...
  36. weerakkodi

    Marine Propulsion: 4 Engine-Fast Gunboat Not Achieving 20 Knots

    I have a some problem about marine propulsion. Assume the 4 engine-fast gunboat is moved by forward two engines. The boat get 10 knots. Then if other Aft two engines operate gradually. You know the boat doesn't get 20 knots speed. What are the reason for that? Explain theoretically? Thanks for...
  37. 24forChromium

    Unmediated propulsion, at all possible?

    By "unmediated" I mean propulsion methods that does not involve ejecting significant amount matter in the opposite direction of propulsion, and I am speaking in the context of space travel, so pushing ambient matter probably won't work very well. I would like to know what is the most plausible...
  38. S

    Why wouldn't this space propulsion work?

    Hi! I'm pretty sure someone would have already made this if it did work, but I don't know why it wouldn't. Can someone explain why this spacecraft couldn't move forward?
  39. K

    Antimatter Propulsion: Exploring Possibilities

    hello everyone, i wasn't sure what category this should go under so General Physics was the safest bet. to my understanding when antimatter and normal matter collides its a 100% conversion into light, is this correct? if so, the conservation of mass says all the mass that was originally there...
  40. B

    Electromagnetic propulsion. (Not?)

    Hi folks, This is such a simple idea that I know I can't be the first to think of it so there has to be a "gotcha". Maybe an induced electric field working in the opposite sense? Is there a kind soul out there who can spare a few moments to educate me after reading what follows? Thanks About...
  41. robbie.kpm

    Is Propulsion Physics Part of Nuclear Physics?

    This is probably the wrong section for this question but what area of physics is propulsion physics. For rockets and stuff. Would that be considered nuclear physics?
  42. S

    Engineering Where Can a Green Card Holder Find Aerospace Engineering Internships in Michigan?

    Hi people of this forum, I have a serious issue at hand right now. I am currently a 3rd year Bachelor student of the Aerospace Engineering at SRM Universty, India. I will be entering my Master's in Aerospace Engineering at the University of Dayton in the fall of 2016 under a Dual-Degree program...
  43. R

    Can Beamed Propulsion be a Viable Method to Reach Pluto?

    The New Horizons results on Pluto are tantalizing. I was trying to come up with methods to get an orbiter or lander there. The problem is at a 31 AU distance from Earth solar power would only be 1/1000th as strong. However, with parabolic mirrors or Fresnel lenses we could focus a large amount...
  44. E

    Can a Reusable Nuclear Pulse Propelled Craft Be Made?

    Hello, my name is Alexander Radchik and I have always wanted to be an atomic play boy. Given the lack of easily obtainable fissile material I have had humble myself to the theoretical use bombs for things that make sense. Regarding my query, I have 2 questions. 1) could a reusable nuclear...
  45. jlefevre76

    Can Relativistic Propulsion Take Us Beyond Our Solar System?

    Okay, I tried searching for this in the forums and didn't really find what I was looking for. So, I'll start a new thread and if anybody has seen this before, feel free to drop a link to an old thread or whatever. Many of our older space probes use/used thermoelectric radioisotope batteries to...
  46. Scaledriver

    Using the Suns gravity for propulsion

    Is it possible to use the sun to slingshot vehicles in order to achieve higher velocities?
  47. Dostetres

    Multiple BLDC per shaft for marine propulsion

    New to the forum, and can't find this info or examples on the web. I'm interested in the possibility of coupling multiple DC brushless motors to a single drive shaft for main propulsion on a 45-50', twin screw boat. Lots of sail boat examples are given, but my interest is in a power...
  48. O

    Good books on propulsion systems?

    Any recommendations for books on Propulsion Systems that arent $100+?
  49. L

    Rocket Propulsion with gravity

    Homework Statement Earlier we considered a rocket fired in outer space where there is no air resistance and where gravity is negligible. Suppose instead that the rocket is accelerating vertically upward from rest on the Earth's surface. Continue to ignore air resistance and consider only that...
  50. T

    Exploring Asymmetry Momentum Transfer for Space Propulsion

    Momentum Drive =============== Just playing with some ideas on rocket propulsion in space based on asymmetry momentum transfer. Any reason why this is not workable? :-p 1. Let m1 = 100 kg robot arm at one end of a cylinder; m2 = 100 kg robot arm at opposite one end of the cylinder; m3 = 10...
Back
Top