Propulsion Definition and 287 Threads

If an apparatus was placed in a sealed box, and was then fixed to the seat of a childrens swing or a pendulum. And then, if it could propel itself (total mass 10kg) forward approximately 5 inches with a single pulse independently of any outside assistance and also without repositioning any...

As an entry level graduate, I'm exploring some ways to become a propulsion engineer. How can I become a propulsion engineer? What all should I consider to learn (both concept wise and software) ? What are other roles related to the path of a propulsion engineer that one must try?

Let's say, the disc has a circumference of 1m, made of steel, or copper if you like. The stator has a north and a south pole facing the surface of the disc, let's say at the perimeter of the disc, one perpendicular to the left and one perpendicular to the right ie opposite sides of the spinning...

Let's imagine a space tourism program where there is a fun part, the tourist can wander freely in space with a jetpack. Let's assume I stray randomly in space, floating leisurely in zero gravity. Then I detach my jetpack, just the time to make a selfie. While fiddling with the phone to setup...

Help me solve... I'm getting errors here..

Hello, Has anyone here started out as a mechanical engineer and shifted to an aerospace engineer? How necessary is an aerospace engineering degree to get into that field? What are some of the barriers that would exist for a mechanical engineer and how would you best get into that field? I am...

Assuming there are four robot inside a stationary spacecraft (mass 2 ton) , robot A has an electric gun that can shoot iron balls weighing 1kg at a speed of 8m/s. These balls collide with red balls at a 45-degree angle in a two-dimensional elastic collision. Each ball has a mass of 1kg. The red...

This is my first time posting, so please excuse any mistakes. I am grasping at straws here. I am working on a Hard-Sci Fi novel, plot, arcs, characters etc. are all worked out and i decided to take the deep dive in terms of Realism. For instance, there are no Fusion reactors. All that is...

Here is a video of the metallic orb captured by a US drone. Wondering about the physics of how such an object could fly.

NASA, DARPA Will Test Nuclear Engine for Future Mars Missions - But then that's been stated periodically in the past. https://www.nasa.gov/press-release/nasa-darpa-will-test-nuclear-engine-for-future-mars-missions Obviously we won't be sending a manned mission to Mars by 2020 or 2024, and...

I have found remarkably little information about ESA's Ion Drive in collaboration with Australia: https://en.wikipedia.org/wiki/Dual-Stage_4-Grid https://www.esa.int/gsp/ACT/doc/PRO/ACT-RPR-PRO-IAC2006-DS4G-C4.4.7.pdf Reference...

while browsing for new propulsion methods I found the following interesting: https://en.wikipedia.org/wiki/Radiation_pressure "Radiation pressure (also known as light pressure) is the mechanical pressure exerted upon any surface due to the exchange of momentum between the object and the...

The discharge coefficient is the ratio of the actual discharge to the ideal discharge and can be measured experimentally. If one were to experimentally measure the discharge coefficient using water, would this value be constant for all incompressible fluids? What does the discharge coefficient...

Hello everyone, I am Abheer and I am a high school student. Few days back I saw an article about RDEs (Rotating Detonation Engines). The article said it is the future of aviation propulsion. I want to ask, is it really so that RDEs are future or the low/high bypass turbofan engines will continue...

https://www.bbc.com/future/article/20220713-how-to-make-rocket-launches-less-polluting

Whicle has 4 wheels, inside is oval closed room with fan that blow inside air to the wing. Wing produce difference in static pressure in direction of travel. Will vehicle move forward or not? If I look just at pressure difference at wing, vehicle will move forward but I know from Newton 3 law...

How did you find PF?: Google Hi folks! Title sums it up pretty well. Alternative propulsion is cool, despite the amount of woo that tends to permeate the topic. I enjoy finding first-principles solutions for far-out claims.

I chose to set the upwards direction to be positive and dM/dt = R = 190 kg/s, so I can solve the problem in variable form and plug in. With the only external force being gravity, this gives M(t) * dv/dt = -M(t) * g + v_rel * R where M(t) is the remaining mass of the rocket. Rearranging this...

Hi, *Excuse the crude visualization and possibly imprecise description - I'm not a rocket scientist :) So, I have a friend that has come up with a "new" concept for a rocket propulsion design, and although I have a hunch that it might not work better than existing designs I cannot really...

When the pulse is given at A, the box move to the right. When it is absorbed at B, the box stop.

Please help me understand why this is a concept that has not been studied? The laser sail is really the only info I can find in this area using a laser from a fixed source. Using liquid nitrogen to cool the mirrors and reflecting lasers off of them for propulsion. I'm a Doctor of Pharmaceutical...

Hey all, Lime here. I've been getting into HHO for a while, and I think I almost have my DIY generator up and running (waiting on eBay 18650 batteries). I was thinking a fun little project is to play around with a few concepts with my new found combustion source. Anybody here know a good way to...

Equation for rocket motion: $$\frac{d \mathbf{P}}{d t} = M\frac{d \mathbf{v}}{d t} - \mathbf{u}\frac{d M}{d t}$$ But $$\mathbf{F}=\frac{d \mathbf{P}}{d t}=M\frac{d \mathbf{v}}{d t}$$ So $$M\frac{d \mathbf{v}}{d t} = M\frac{d \mathbf{v}}{d t} - \mathbf{u}\frac{d M}{d t}$$ And $$-...

This is about the famous, classic experiment of Magdeburg hemispheres with the Wikipedia link below: https://en.wikipedia.org/wiki/Magdeburg_hemispheres. "The experiment was designed to demonstrate the vacuum pump invented by Otto von Guericke - but also the tremendous 'strength' of the...

Fluid can exert force to object(move object) only through pressure and tangential stress caused by viscosity. if we look at balloon rocket ,here is Newton 3 law action-reaction,but this 3 law as usual don't tell nothing how fluid really exert force to the ballon.. it exert through pressure...

image veichle with 4 wheels ,beams rotate about point " A",each weight can slide radialy on own "beam" ,so weights rotate in cirlce but with different tangential velocity .Different tangential velocity produce greater "centrifugal force" in one part of circle ,so weight "push" at veichle...

2500 N [south] + 3200 N [south] = 5700 N [south] 5700 N [south] - 6000 N [north] = 300[north]

Let me preface this by saying I have no background in physics or any of the above other than hours and hours of reading. Could someone explain why (if a method was developed) we couldn't use EFA as a thrust system for a rocket? My reasoning is instead of using fuel to fight gravity and push...

Homework Statement:: Simualte the behaviour of water around an mhd inductive thruster Relevant Equations:: https://www.comsol.fr/paper/download/45837/Pintus.pdf Where can I start this simulation ? What is the required software ? [Mentor Note -- thread moved from the technical forums]

In order to build a small mhd propulsion ship for a physics project, I'm wondering if the magnets we find in hard drives carry enough magnetic field power to function in such an experiment.

I’m trying to find something that can replace Ion engines in my Star Wars story. Ablative laser propulsion seems like a good bet because it works in both atmosphere and a vacuum and just seems better than Ion engines.

I’m wondering if a lander/rover landed on an asteroid with a very low gravity, and we wanted to make said rover move around the asteroid, would it “float” away because of the low gravity? Wouldn’t the normal force and the gravitational force equal 0? If we added a propulsion system, how would we...

Tesla+SpaceX= supersonic VTOL suborbital electric jet? “I have an idea for a vertical takeoff and landing supersonic jet.” — Elon Musk, every time the subject of electric planes comes up, to include almost never using the VTOL abbreviation for some reason that’s probably very unimportant. —...

Hello all: I have a small question about nuclear propulsion , why everyone are trying to use it ,and why this wired choice of nuclear option , retrofitting a nuclear reactor to mount it on the rocket , isn't that a little dangerous , why they don't use other option or research it , there is few...

1.) Ion drive 2.) Black hole starship 3.) Fusion Rocket 4.) Fission sail https://en.m.wikipedia.org/wiki/Fission_... 5.) Halo drive https://arxiv.org/abs/1903.03423 6.) Horizon drive https://www.tsijournals.com/articles/pro... 7.) Pitch drive, Diametric drive, Disjunction drive...

Summary: Which of these hypothetical propulsion methods is the best for a spacecraft during Interplanetary flight? Let’s just assume all at this point are cost-effective at the time. Consider the •Safety of the engine •The speed •The efficiency 1.) Monoatomic hydrogen propulsion 2.)...

Hello, just wanted to know what is recommended after undergrad Physics to get into a career developing electric propulsion systems, or anything to do with Plasmas and future propulsion devices?

Let’s ditch chemical fuel (even like scramjet, aero spike and SABRE) and venture to the future, for only thus we can become a multiplanetary species, and establish a true interplanetary/interstellar transit system. For atmospheric ascent: 1.Fusion reactor (thermal power)+Thermal ramjet...

I have been thinking about this subject for some time now, based on the following considerations 1) Many companies are working on Electric Aircraft Propulsion, high energy density Li-Ion batteries are used to power Electric motors and they drive propellers. This is the approach every one is...

Hey guys. I wanted to ask your opinion about something . I'm interested in MHD propulsion and i know so far that has been inefficient against the usual propulsion systems up to today. Do you think it worths someone getting deeper into it ? I'm thinking how awesome would a practical...

I've been interested in relativistic spacecraft since news of the Breakthrough Starshot project announcement a few years ago. Breakthrough Starshot's method of laser propulsion still has many technical hurdles needed to be crossed. So I'm wondering what you guys think the first forms of...

I recently came back from a cruise on MS Eurodam. The ship was equipped with two 17.6 MW Azipod propulsion systems. The captain explained a bit about them in a Q&A session, and I researched a bit more because I'm curious as an engineer. I'm sharing it here on PF for the benefit of other...

Here is a video that dicsusses it, but it sounds awfully science-fictiony to me.

Water, is my interest ,in it swimming ,surfing in Sydneys' Pacific rollers to feel the turbulence ,SCUBA , boats, pumps ,pipes, Hydrodynamics, treatment, mini-hydroelectric generation. Currently working on improvements to sculling with unique "scullocks" foils on the blades of oars. Human...

Hi, How to calculate the position in time by applying a force, like a Thrust, not in the center of mass: I only know about the linear and angular formulas: Pos/rotation = 1/2 * F * Time^2 I have struggled finding topics about this maybe because i don't know the correct nomenclatures and maths.

I saw a video on youtube and it explains in a vague way how the system works, so there is a potential difference between two sets of electrodes and air between them is ionized in the presence of the E field but how muhc is it ionized? Because I get the impression that the ionization is not in...

Hi, I recently came across Positron Dynamics, a company working on a fusion propulsion system. You can watch this presentation given at Breakthrough Discuss 2018. They also got a grant from NIAC. Rather than trying to create and store positrons, they use Na-22 as a source. They also patented...

I mean by the best the one that use the least energy to produce the grater force capable of carrying weights . Say you have a pulley attached to a ceiling with height of 3 meters, around the pulley is a string that attached to a 30 kg weight and on the other side of the string you want to use...

Hello everyone, In stand up paddle boarding, the correct way to use the paddle when moving forward is to have the paddle convex side facing rearward while the paddle pushes water backward. This is explained by the fact that the paddle generates a lift force pointing backward if the convex side...

Homework Statement Homework Equations p=mv j=Δp[/B] The Attempt at a Solution I am confused as to how to approach this problem. so it looks like squidwards mass is changing from 1.2kg to 1.1kg after he shoots out the water from his butt. I know that momentum is conserved so 1.1*2.7 -...