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Questions tagged [propulsion]

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How do rockets maintain their direction in a stable way? [on hold]

With such a huge force behind the rocket, it should flip over almost immediately. Surely the relatively small wings on the sides do not provide sufficient resistance to keep it from flipping over?
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2answers
131 views

Would throwing a heavy object in space work as a form of propulsion in space?

I watched the "Helping Hand" episode of Love, Death & Robots on NetFlix, where the protagonist is adrift in space. Every second she is further from her ship, and when her tank is out of oxygen, ...
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1answer
17 views

Derivation of the expression of a propeller pitch distance

The pitch distance of a propeller is given by: $$p = 2\pi r \tan{\beta}$$ where $\beta$ is the pitch angle and $r$ is the radius. I cannot find how this expression was derived. Could you please ...
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3answers
67 views

How do rocket engines work in EMPTY space? [duplicate]

So I just read this and it didn't make any sense It is not necessary for the rocket exhaust to push against anything EXCEPT THE SHIP ITSELF. You see, when the combustion of fuel takes place ...
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1answer
33 views

Standing waves in raptor rocket engine test

Stopping the video of the recent test of the raptor rocket engine, one can see a standing wave forming in the exhaust gases: https://youtu.be/MAAzbjG_Duc?t=23 I was wondering what might cause a ...
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2answers
63 views

Would a horizontally-imbalanced maglev train car be propelled by the force of gravity?

I am wondering if a horizontally-unbalanced maglev train car would be propelled forward by the pull of gravity. This would result from the train car's electromagnets producing unbalanced magnetic ...
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1answer
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1answer
58 views

Is it possible to use an accelerator/collider as a space engine? [closed]

I was just trying to get a discussion going about physics that we can already create. I did not realize that I would have to write a paper to ask a simple question. Is it possible to use an ...
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2answers
65 views

Vacuum thrust, and how it is proven

Let’s talk about “Vacuum Thrust”. Simply put, thrust that is exerted in a vacuum. Space is a vaccum correct? So therefore there is no matter is space, it is just empty space. Thrust is measure in ...
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1answer
138 views

What is installed and uninstalled thrust? [closed]

I am reading Elements of propulsion.He starts introduction of thrust equations that involve installed and uninstalled thrust.Can somebody please define what uninstalled thrust and installed thrust is?
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1answer
39 views

Using a ball on a string for propulsion in space

My friend presented a bit of a puzzle to me, and I can't remember enough physics to say whether it would work, and more importantly, why. It goes like this: Imagine you are an extremely dexterous ...
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1answer
33 views

How would you calculate final velocity for the simple electric train experiment?

Alright, so basically I have an experiment to make, which is similar to the simple train video on youtube. I want to test different voltages & gauges of copper wire to see the changes in velocity. ...
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1answer
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Would all types of advanced non-chemical propulsion for spacecraft, cause nearby objects to be “blown away”?

Would all types of advanced non-chemical propulsion (such as ion, plasma, fusion etc) for spacecraft, cause nearby objects to be "blown away" (like when chemical rockets takeoff)? Also would they be ...
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2answers
120 views

Laws of motion in relation to balloon and rocket

Question: A spherical rubber balloon inflated with air is held stationary, with its opening, on the west side, pinched shut. (a) Describe the forces exerted by the air inside and outside the balloon ...
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1answer
127 views

Orbital Hyperloop for Approach to $c$?

We have a bunch of "orbital catapult" ideas to get things into orbit - most involve some sort of loop with mag levitation in vacuum. There is a practical limit on the top speed here due to whatever is ...
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0answers
225 views

Could the energy (voltage) required by a ionocraft style EHD thruster be decreased through combining multiple small ionocraft?

I saw a lot of ionocraft designs are focused on building them as big as possible to increase the amount of air the ionized air could push down. This got me thinking. Since one big problem facing ...
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2answers
67 views

Would it be possible to propel a spaceship by pushing against the sun's magnetic field?

Would it be possible to power a space ship by generating a magnetic field opposed to the sun's? For example, the spaceship could generate a magnetic field using massive coils of superconducting wire. ...
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1answer
311 views

The interstellar medium reflects extremely low-frequency radio waves. Could we use this fact to build a more efficient photon rocket?

According to the equations of MHD, electromagnetic waves cannot propagate in a plasma if they are below the plasma frequency. (For more information, see this question about astronomical-wavelength ...
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1answer
55 views

Rocket fuel consumption

Consider a velocity change $dV$ for a rocket accelerated by an on-board thruster. Is the total amount of fuel consumed proportional to $dV$, or to $dE$, where $dE$ is the change in kinetic energy, or ...
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2answers
297 views

Rocket Propulsion and Bernoulli's Theorem

This is what my textbook says on rocket propulsion:$\hspace{75px}$ Questions: The beginning of the textbook excerpt says that the fuel is converted into a gas at high pressure. Does this mean that, ...
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1answer
49 views

How to calculate rocket thrust? [closed]

I’m trying to calculate the thrust of a theoretical rocket (for a simulator). The formula I’m using is F = pVeA . I can get the exhaust density by using the gas formed during combustion and then ...
0
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1answer
145 views

How to calculate rocket Burn Rate?

I’m trying to calculate the burn rate of a theoretical sugar rocket (for a computer game). The equation I have is $r = aP^n$ . Where $r$ is the burn rate, $a$ is the burn rate coefficient, $n$ is the ...
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1answer
59 views

Is it possible to get propulsion using radio waves?

Electric current is generated in an antenna by radio waves, if current is already there in the antenna would it produce any force? If so, it would be possible to use background electromagnetic ...
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2answers
102 views

A conceptual propulsion device based on instantaneous energy transfer of relativistic mass

Setup Consider two objects $O_1$ and $O_2$ of mass $m$ each. The objects are connected one to another with a rod of say length $2\cdot l$. At the middle of the rod, $M$, there is a rotational joint ...
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3answers
214 views

Nuclear reactor in a cruise missile. How?

So it is declared, that there are cruise missiles with nuclear reactors on board. As I understand, when it's working, the neutrons keep flying from off the fuel. Neutrons give induced radioactivity. ...
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3answers
3k views

Rockets in vacuum vs. Rocket on earth

Recently my physics teacher during a rant said something that piqued my interest. Heres what he said "There are more problems visiting other stars if you wanted a rocket to go 99% the speed of light ...
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1answer
30 views

Reduce velocity in the Space

As per sketch there is a ball filled with liquid launch from A point to B point at 10 meter per second.the ball is spinning clockwise and moving towards B point.but the liquid in the ball is spinning ...
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1answer
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Reactionless propulsion method (not physics heresy!?) [closed]

Description of process: water or some other low viscosity fluid is rotated in a cone by an impeller or other means, and then ejected tangentially at the point where it climbs the highest (due to ...
2
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0answers
94 views

How efficient is rocket engine clustering?

So I watched a video where a guy built his own rocket from scratch. I noticed he used some F15-0 rocket engines* to get this thing as high as 300m (he's built other rockets too, where he used the same ...
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3answers
64 views

Can we use ions in space to propel and power spacecraft?

If space contains mostly ions (whether positive or negative), then why cant a spacecraft “absorb” them with simple anodes/cathodes, separate them, and repurpose the ions for spacecraft electricity (e-)...
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0answers
31 views

What would one need to do to get an amateur satellite into orbit? [closed]

I've recently become interested in amateur satellite packet radio, and I've seen that the bandwidth and thus the bitrate is extremely low on most amateur satellites, not even factoring in noise. So I ...
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1answer
48 views

Could you build a “space tunnel system”? [closed]

With the limitation of fuel that can be taken on a space craft, would it make sense to build a propulsion system in space instead? For example via rings that are aligned very well and are positioned ...
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1answer
119 views

Can anyone explain why this Tesla coil stopped rotating?

I am doing a similar project as shown in the video Arcs change shape in my vacuum! RIP Tesla Coil :(. I am working in Tesla coil propulsion. Can anyone explain why this Tesla coil stopped rotating?
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1answer
336 views

How much force would be required to lift a 200KG contraption/machine+human vertically 3-5 feet and keep them hovering in position?

A friend an I are designing what could be described as a hovercraft(bike). We have a basic idea of what we want to do in regards to design, but we can't start assembling it until we know the forces ...
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0answers
28 views

Methods of propulsion of hydrogen plasma

What would be the best method of accelerating a continuous flow of hydrogen plasma to 300 000 m/s in a straight line. I have thought about a rail gun approach but don't think this would be suitable ...
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1answer
212 views

Use a neutron source as a spacecraft propulsion method

Is it viable (or even possible), to use a neutron source as a form of propulsion for a spacecraft? I imagine this drive would have similar trust/specific impulse characteristics as electric propulsion ...
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0answers
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Is the following a valid question re: The Coulomb force?

I'm making up some practice questions for a course on electromagnetism and electric circuits. I like to make the students think, but I also want to make sure that my questions aren't terribly ...
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1answer
108 views

Is water a possible fuel for jet engines?

Jet engines can run on almost any fuel, and the operating temperatures of modern jet engines' hottest sections are anywhere between 3000 and 3150 degrees F (1648 and 1732 degrees Celsius). Does that ...
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1answer
33 views

How is an airplane propeller screw pitch calculated?

I know a 30" * 12" airplane propeller means the prop has a diameter of 30inches and will travel 12inches forward per revolution, but what I don't know is - what angle of attack does the propeller ...
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0answers
49 views

How fusion reactor could be operated on space craft? [closed]

Considering that space craft uses engines only during acceleration and deceleration, how fusion reactor will be operated? For example: it will be started / stopped for each maneuver will be working ...
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1answer
195 views

Reactionless Drive Concept - Will it Fly? [closed]

Below presented a concept for a electromagnetic thruster. Basic Concept Suppose you have two identical current carrying solenoids, Solenoid A and Solenoid B that are firmly mounted to the inside ...
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1answer
59 views

Would a propeller attached to, but inside a sealed box work? [duplicate]

I can't find anything online about this, maybe I'm just dumb, but I was wondering, if you put a propeller inside of a air tight, water tight box, and turned it on, would it propel the box? If not, why?...
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1answer
47 views

why cant we use air breathing engines in rockets

why cant we use air breathing engines. In rockets after achieving high speeds i.e first stage using solid propulsion and after achieving high mach using ram or scram jet.
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2answers
362 views

Does a rocket engine apply more power as the rocket's speed increases? [duplicate]

To clarify my level of knowledge, I'm a high school student all the way through AP Physics C: Mechanics. So, let's imagine that there is a rocket travelling through the vacuum of space (ignoring ...
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1answer
75 views

Wouldn't the air accelerating over the top of the wing push the wing forward(thrust)

A wing accelerates air on top of itself. Does this cause any forward thrust? I would think so because the air is accelerating backwards which should create an equal and opposite reaction forward.
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1answer
235 views

Ion engine: purpose of magnetic field

I have a question about the gridded electrostatic ion engine. In the ionisation chamber there are several magnet rings that create a magnetic field inside the chamber. But what is the purpose of ...
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2answers
401 views

How are gravity tractors possible?

I've heard about how NASA is planning to redirect asteroids by having a satellite tug on it gravitationally using a large enough bolder, but how is that possible? I thought that changing the ...
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1answer
28 views

Ion propulsion lifter [closed]

Me and some teammates are trying to build an Ion propulsion based lifter for some kind a physics challenge: https://www.youtube.com/watch?v=vzZy1Aqleno Firstly, We don't have a power supply of 30kv ...
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0answers
54 views

How do Ion thrusters Bias their grids

Recently when I was thinking about Ion thrusters, I realized I didnt understand one fundamental thing - Grid potentials. How do they maintain the voltage between the grids. One thing that I got in my ...
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1answer
82 views

Why are Ion thrusters so energy hungry? [closed]

Ion thrusters need a lot of energy. But I don't understand why. So, one thing I understand is that it takes a lot of energy to take achieve a high exhaust velocity ( since kinetic energy is ...