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. MattRob

    Gas Dynamic Mirror Fusion as Spacecraft Propulsion

    Hello again, Physics Forums. I'm designing a Sci-Fi story and I'm fleshing out the background details. For it's sake, education, and my own curiosity, I was wondering if I could have some help with a few things related to the physics of it. A bit of an armchair Rocket Engineer, I'm using...
  2. D

    Nuclear pulse propulsion with low Z propellant?

    I've been doing some reading about Orion-drive spacecraft , but I don't understand the requirement of a high Z propellant like tungsten. Assuming that the pulse unit were detonated further away from the craft to prevent it from drilling a hole in the pusher plate due to its narrower angle, why...
  3. A

    US Navy Nuclear Program (Propulsion)

    Anybody here who has gone through the Navy's Nuclear Propulsion program? Wanting to get some insight on the program
  4. M

    Magnetic Propulsion - Possible?

    I am new to this forum, so please excuse my ignorance. I was thinking about how everything in the universe is round, right? Well, the Earth is made up of two magnetic poles. North pole, and south pole. It is what keeps the Earth stabilized. Is it possible to utilize round magnets for...
  5. H

    Large ship propulsion. (Orion revisited)

    Colony ship propulsion Hello. I've identified a huge problem in my novel and would appreciate any help. Short version: How much mass can you safely move, given 100-200 years travel time, to a nearby star system using the world's nuclear stockpile for pulse propulsion? This would be...
  6. M

    Propulsion mechanism of a ferris wheel

    How does a the propulsion mechanism of a ferris wheel propel the ride? A diagram would be helpful
  7. M

    Aerospace Engineering for Propulsion: Is It Worth It?

    Should I get into Aerospace engineering if I am not interested in aircraft/ spacecraft design at all? I am interested in propulsion and I will probably get an advanced degree in plasma physics or nuclear engineering. I am not sure if a degree in aerospace will give me enough background. Here...
  8. Z

    Electromagnetic propulsion systems

    Currently working on a pet project, looking to build a model for accelerating a relatively large mass on a short straight track type system. Can't find much information about the way "Maglev" trains accomplish their propulsion or the way the electromagnet systems work to keep the train...
  9. T

    How Does Rocket Propulsion Affect Burnout Metrics and Altitude Achievement?

    Question I) For a single stage rocket: T = 955.23 kN, n = 16, Isp = 400 s and m0 = 70, 000 kg. The rocket is launched into a vertical trajectory. Neglecting drag and assuming g is constant at its sea level value, Find (a) the time until burnout, (b) burnout altitude, (c) burnout velocity, (d)...
  10. V

    Physics of Propulsion: Learn About Space Travel Tech

    Hey all, first time poster. I have had a long-standing interest in astrophysics and space-related travel. I read a lot about such topics during my free time and from what I've read, only reaction mass (rocket) engines are currently possible for earth-to-space launches. This gets both...
  11. C

    Want to Work on Plasma Propulsion

    Okay so here is my question. I want to work on ion based propulsion in particular plasma propulsion. I'm currently finishing off a degree in Space Systems Eng. and I'm wondering where I should go from there. I would think that a second degree in physics, chemistry or electrical engineering...
  12. P

    Rocket Propulsion - Varying mass

    Homework Statement A rocket at rest in space, where there is virtually no gravitational force, has a mass of 2.55 * 105 kg, of which 1.81*105 kg is fuel.The engine consumes fuel at the rate of 480 kg/s and the xhaust speed is 3.27 m/s. The engine is fired for 250 s. Find the thrust of the...
  13. R

    Grade 12 Rocket propulsion Question

    Homework Statement A rocket for use in deep space is to have the capability of boosting a pay load ( plus the rocket frame and engine) of 3 metric tonnes to an achieved speed of 10000m/s with an engine and fuel designed to produce an exhaust velocity of 2000m/s. a) How much fuel and...
  14. BitWiz

    Calculating Ship Acceleration with Gauss Gun Propulsion

    Hi, Say I have a spaceship in ideal gravity-free, friction-free space. I have a source of power capable of producing a maximum of E joules per second, and I want to use some form of continuous electric propulsion, such as a Gauss gun or ion thruster, to get around. I have these questions...
  15. M

    Inertial Propulsion: The Potential of Eliminating Electron Mass in Graphene

    Electron Mass Effectively Eliminated in Graphene http://archive.sciencewatch.com/jan-feb2007/sw_jan-feb2007_page6.htm Since reading this I've been bothered by the niggling implications of a system in which the value of mass can be varied.. particularly with regards to propulsion. It...
  16. F

    Harnessing Light for Spacecraft Propulsion

    It is said that aiming a laser from earth, the moon, etc, could be used to propel a spacecraft receiving such a laser beam. It is also said that a solar sail could use the reflection of photons to move through space. Now my question is, while impractical what stops an on board laser being...
  17. Z

    Could you use contained light as a form of propulsion?

    I was reading about how an astronaut came up with an idea to change the trajectory of meteors by bringing a spacecraft close to them where it's gravitational field would eventually move it slightly. It made me wonder if you couldn't use light like that. So say (hypothetically of course)...
  18. E

    How Do You Calculate Thrust in Aircraft Propulsion Technology?

    Can anyone help me? I'm doing a question on aircraft propulsion technology and I'm stuck. The question is: 'If the mass of air through a propeller is 1000 Kg/s, the aircraft's velocity is 100 m/s and the slipstream velocity is 120 m/s, calculate the thrust? Attempt at answer...
  19. M

    Solve Rocket Propulsion Problem: a = ((Vr)(k))/(1-(kt))-g

    Here is what I know a = (-Vr/m)(dm/dt)-g, I also know that 6. : m=m(initial)(1-kt). Under the conditions of 6: Show that a = ((Vr)(k))/(1-(kt))-g. I have tried to solve this problem by substituting dm/dt=-km(initial) into the first equation I have listed (a = etc.) but I have had no luck. Please...
  20. J

    Is a Mechanical Engineering Degree Enough for Propulsion Research?

    Hi everyone I'm a freshman majoring in mechanical engineering, although I wish it were aerospace eng but my school doesn't offer that. I'm interested in researching propulsion. Could I do this with a major in mechanical engineering? Also if I went to grad school for a phd in aero, is it...
  21. R

    Could Solar Energy Beams Enable Interstellar Travel?

    Ever since I saw stephen hawkings universe doc's, I've been wondering about one creative scenario he presented. surround our sun with solar energy satellites. Draw and store the energy in the satellites. satellites fire this energy in beams (synchronized) into one satellite which then...
  22. M

    Rocket Propulsion Differential Equation Solution Help?

    Homework Statement Consider the case of a rocket taking off vertically from rest in a gravitational field g. The differential equation is given by m\dot{v} = -\dot{m}v_{ex}-mg Assume the rocket ejects mass at a constant rate, \dot{m}=-k (where k is a positive constant), so that m=m_{0}-kt...
  23. K

    Seeking Info on Plasma Propulsion Engine Design

    I wanted to ask about plasma propulsion engine. Plasma can be made by using radio waves. How this part of device looks like?(I know something, like an antenna, is used) I searched the net, but I didn't find anything. Thanks in advance. P.S Please explain as simple as you can
  24. V

    Down-scaled nuclear pulse propulsion

    A smaller ”boom” I'm currently writing a science fiction novel, and while I'm certainly no physicist, I still aim to minimize the use of handwave devices built from unobtainium. It appears that the only propulsion system realizable with technology in use today or in the near future which...
  25. G

    Radioactive magnetism as propulsion

    Radiomagnetism or radioactive magnetism. Has any research been done on this phenomenon as a source of propulsion. Are we thinking too small? Can the various levels of radioactivity affect magnetic propulsion by increasing its magnitude. What would be required to observe this on a large scale...
  26. B

    Amphibious Bike Propulsion Problem

    Hi Guys, I've made an amphibious bike, shown below. Basically, it's a bike which you can use to cycle along the road, down the slipway into the water with litle/no changeover, and then pedal off through the water. It all works, and floats, but I'm struggling to find a way to propel it in...
  27. N

    Is it able to convert electricity into propulsion force?

    Is it possible to convert electricity into propulsion force? My friends and I are discussing about this subject. Is it possible to build a device which can convert electricity into propulsion force? just so you know, we have incessant electricity produced by solar cells and if that...
  28. I

    Undergrad prep for research in rockey propulsion?

    I think that R&D in rocket propulsion is something that I would like to do. I am just wondering what would be the best prep for it? Aerospace engineering or physics? I am going to study physics and maths at the University of Toronto because it interests me and I believe that it can open a...
  29. S

    Dyson Bladeless Fan, Inducted Airflow Propulsion, Personal Transportation

    I remember once observing a thread in a discussion forum by someone trying to build a backpack helicopter. Various people warned him about sprung-weight-vs-unsprung-weight, hazards of stability and flight control, etc. But ever since reading about James Dyson's bladeless fan and the...
  30. K

    Underwater Express power and propulsion

    I am fascinated with the idea of supercavitating subs, and DARPA's underwater express program has caught my fancy. A sub that can go faster than 100 knots submerged, now that is too cool. I am curious as to speculation on how Electric Boat will power and propel the ship. The idea I personally...
  31. J

    How Long Does It Take to Accelerate a Motorcycle from 0 to 100 km/hr?

    Homework Statement You must find the time it takes to accelerate (at constant applied torque) a motorcycle from 0 to 100 km/hr, given: Rider mass: 75 kg Bike total mass: 190 kg Torque at crankshaft of motor: 105 Nm Front and rear wheel masses (10 kg and 17 kg respectively) Radius of...
  32. S

    U238 for Aerospace Propulsion (Traveling Wave Reactor)

    You may have heard a lot of buzz in the news recently about the Traveling Wave Reactor, a concept being developed by TerraPower Inc, which uses depleted uranium (aka U238), instead of the usual rarified U235. http://en.wikipedia.org/wiki/Traveling_wave_reactor Apparently, the...
  33. A

    Electromagnetic Propulsion Theory

    If a metal plate, let's say 10 feet by 10 feet, is magnetised to a positive polarity, and a magnet that is also a positive polarity is place on the plate, will it float? and furthermore would it move across the plate if a force propelled it forward?
  34. O

    Space Propulsion Research: What's Next? Best College Major for Study

    I'm curious, what do you think the "next generation" space propulsion technologies will be, and what would be the best college major in order to do research in that field?
  35. W

    Is Asymmetric Capacitive Propulsion at Play in Meniscus Propulsion?

    Earlier this year, a team of scientists demonstrated a tiny boat that uses surface tension, but no moving parts to navigate through water (see http://www.pitt.edu/news2009/Cho.pdf" ). I wonder if a boat with hydrophilic material at the back and hydrophobic material at the front can propel...
  36. J

    Calculate Speed of Exhaust Gas in Rocket Propulsion

    Homework Statement A Rocket is propelled as a result of the very rapid ejection of exhaust gas from the rear of the rocket. Given that the initial mass of the rocket and fuel is 5000kg and the 4000kg of fuel is burned in accelerating the rocket to a speed of 600m/s, calculate the speed of...
  37. M

    Alternative Propulsion Methods for Maglev Models Using DC Motors

    Hey there! I need to build a working model of a maglev-train, which will hover over permanent magnets on a track, and which will have to have a propulsion system. My question is whether there is a way of getting an accelration not using a propellar? As part of the project, I've been given...
  38. V

    Zero Force Propulsion: A Futuristic Concept?

    What if we don't NEED to use any force whatsoever to propel a vehicle? What if we could negate the net external force and just keep the vehicle going with a constant velocity with the appropriate magnitude? But what could we use to propel the vehicle at any given time and not add any other force...
  39. S

    New Superconducting RF Cavity: Potential for EMdrive Propulsion?

    Here's an interesting article about a new breakthrough in the manufacture of a superconducting radio-frequency cavity: http://nextbigfuture.com/2009/09/superconducting-radiofrequency-cavity.html If this new cavity were tested for EMdrive purposes, could it reveal a new mechanism for...
  40. U

    Where Is Water Pressure Greatest in Water Propulsion Systems?

    water propulsion? whoosh! I've seen this question written three different ways and each gives three different answers. I'm just not sure how the answer is gotten. Here is what I see when I see the question...either two straight lines to depict a pipe for water, or a straight line and a...
  41. S

    Nuclear-Electric SSTO Vehicle: Best Propulsion Mechanism?

    I've been fascinated by the idea of using a nuclear reactor (either pebble-bed or particle-bed)as a powerplant for an aerospace vehicle, but of course there is the problem of coupling the thermal energy to the propellant flow by direct contact without having bits of radioactive debris from the...
  42. C

    Gyroscopic Propulsion: Could Gyroscopes Levitate Objects?

    could gyroscopes be used to produce upward linear thrust? or be used to push something along at least? i was looking at an attempted recreation of teslas flying stove and i was wondering if powered gyroscopes could be placed at what he referred to as "eccentrics" to produce upward momentum and...
  43. G

    Rocket Propulsion: Solving a Variable Mass Equation of Motion

    State the fundamental equation of motion for a particle of variable mass. A rocket of initial mass m0 is fired vertically, under the influence of a uniform gravitational field, and expels propellant at a constant relative velocity c downwards. The propellant is completely consumed after a...
  44. R

    Hydraulic motors for hovercraft propulsion?

    For a proposed Hovercraft propulsion system, 1a) Is it feasible to use separate hydraulic motors to power a) four wheels for land propulsion, b) two water propellors for water propulsion c) two lift fans d) six actuators for retracting / deploying the wheels and propellers. 1b) Can the...
  45. B

    Anomalies in the Asymmetrical Capacitors for Propulsion Tests

    I realize Biefeld Brown is a verboten topic on this forum but I believe the admins overlooked the anomalies sections in some NASA studies when coming to that decision. In the http://gltrs.grc.nasa.gov/reports/2004/CR-2004-213312.pdf" tests, in the Observations section it states: After...
  46. P

    Magnetic Propulsion: Can a Magnetized Ship Reach the South Pole?

    Can a magnetized ship go to the South Magnetic Pole on its own accord? Let's say it is currently located in the Southern Hemisphere so the attraction from the N-pole in the South Magnetic Pole is stronger than the attraction from the S-pole in the North Magnetic Pole. Let's also say that there...
  47. J

    Fusion Propulsion for Spacecraft

    I found this presentation on Fusion Propulsion here: http://fti.neep.wisc.edu/presentations/jfs_jannaf_1205.pdf" The Gas Dynamic Mirror seemed the most interesting and I got a lot of Google hits on it, but here are some guys working on actual proof of concept hardware...
  48. T

    Can Fusion Propulsion Be Optimized with Altered Magnetic Field Configurations?

    I came up with this during idle afternoon. Don't know if it's worth something but I wanted to discuss it with someone. Basically, outline of business part is given on the picture Horizontal tori are basically tokamaks and vertical pipes are "fusion combustion chambers" where working fluid...
  49. V

    Mobile engine propulsion system?

    would it be possible to have a system that has 4 engines on the corners of a 'fuselage' and these engines can rotate about joints giving the plane propulsion and deceleration. also this helps the pilot manipulate tha plane a lot easier (sort of like a helicopter). NOTE: these are like the...
  50. S

    Submarine Propulsion Questions Answered

    Hi, I was looking at the following diagram and have some questions: Is the purpose of the pumps to transport liquid of one temperature to another section of the loop? Is it more efficient to use steam to turn turbine or to use water to turn a turbine? (Is hydroelectric more efficient...
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