Questions tagged [rocketry]

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3answers
46 views

Rocket vs aeroplane? Difference in take off?

Although both aeroplane and rocket burn fule and eject smoke but Why aeroplane moves and runs horizontally before take off ?why does not it takes off at its original/initial place just like rocket?
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1answer
43 views

Inefficiency of intermittent burn in rockets

Imagine I have a combustion chamber with a nozzle. There is a high pressure oxygen bottle and a high pressure gaseous fuel bottle connected to the chamber. Would the fuel efficiency be lower if I ...
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0answers
86 views

Flow through an Annular Orifice for Pintle Injector

Our rocket team is trying to finalize the design of our injector for a small liquid rocket engine. The current analysis challenge is verifying the correct pressure drop across the annular orifice ...
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0answers
53 views

Isp Output of NASA CEA

I have 2 questions related to NASA CEA's Isp values in the output file. When looking through the output of NASA's CEA tool, I am trying to understand the difference between its "Ivac" output and its "...
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1answer
48 views

How does a nuclear powered rocket engine work?

Nuclear power always require some way of converting the energy from nuclear to electrical or mechanical to be useful. For example, in a nuclear power generation facility, this is done through heat/...
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2answers
60 views

What are the design trade-offs in the different rocket engine cycles for liquid propulsion systems

Liquid propelled Rocket engines work on various cycles such as pressure-fed, pump-fed(gas generator,staged combustion, expander, etc) and these have various design trade-offs between complexity, ...
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0answers
7 views

Does the coefficient of force for a built rocket engine change with chamber pressure?

So I understand that the force coefficient (force/thrust/nozzle thrust, whatever you want to call it) is a function of chamber pressure, or more specifically nozzle stagnation pressure, according to ...
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0answers
18 views

Question with regard to spacex raptor engineand other full flow staged combustion engines

The diagram linked is unofficial but I've looked at other diagrams which are similar. The coolant is pumped in at a high pressure much higher than the maximum chamber pressure of the rocket the ...
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0answers
17 views

How to minimize temperature increase caused by compression of a cryogenic liquid in a multistage high pressure turbopump?

The cryogenic fuel I'm using is methane at 100 K and 300,000 Pa. Based on my calculations, after compression, the pressure is 55 MPa and using the ideal gas equation the temperature is approx. 800 K. ...
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1answer
34 views

Is there an easier way to calculate rocket engine Isp?

I am trying to calculate the $I_{sp}$ of a rocket with a thrust of 500 kN. I know that you can calculate $I_{sp}$ with $I_{sp} = \dfrac{v_e}{g_0}$. However, to calculate $v_e$, you need the $I_{...
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1answer
95 views

What's the minimum area ratio required to achieve choking in Converging nozzle?

Is there any equation for minimum area ratio (Throat area (At)/ Combustion Chamber area (Ac) ) required for choked flow in convergent nozzle (just like equations for minimum Pressure ratio and ...
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1answer
50 views

How to design a transfer function for a Model Rocket?

I am building a roll stabilized model rocket. I am beginner at controls systems. How do I find out the transfer function of the rocket. Although, I am aware of definitions and stuff of control systems....
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2answers
97 views

Why is Rocket Nozzle CFD done in 2D instead of 3D?

Why do I see rocket nozzle CFD like the one here in this SpaceX video done in 2D? Real Fluid flow is three dimensional and involves an x, y and z axis. Is fluid flow done in 2D only because computers ...
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1answer
62 views

Liquid Rocket Plumbing and Instrumentation Diagram: Standards and Presentation

I'm working on a team to build a liquid sounding rocket as a school project. We need to present our plumbing and instrumentation diagram, but we are butting heads on what program and standards we ...
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0answers
38 views

Method of Characteristics nozzle - outputs area ratio?

I am designing a rocket engine as my final project at college, and I tried using a MatLab code developed by youtuber JoshTheEngineer. However, after running the code, it seems that the output points ...
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0answers
38 views

Is it possible to protect electronics on a cubesat from 100-1000g of acceleration

I am currently researching the feasibility of setting up a coilgun that launches Cubesats for a paper.
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2answers
92 views

the speed of the exhaust

This is from Stephen Hawking's latest book; Brief Answers to the Big Questions. The speed at which we can send a rocket is governed by two things, the speed of the exhaust and the fraction of its ...
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0answers
21 views

What factors besides nozzle geometry and propellant's affect engine ISP? How can one optimize ISP?

In the design of a Rocket engines, it is understandably desirable to have a more efficient engine. Ensuring the gasses coming out of the engine comes out straight, and the chemistry of the ...
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2answers
59 views

What is the purpose of building multistage rockets, rather then packing more fuel into a single stage?

Reading an article about multistage rockets (not educated at all on the topic), and from the get go it seems to assume they are used/need to be used.
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1answer
95 views

Combustion Chamber Back Pressure due to gas injection

I am trying to calculate prior to testing the expected back pressure resulting from injecting gaseous oxygen through an injector orifice (choked) into a rocket combustion chamber before ignition. I ...
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1answer
306 views

Increase thrust of ion thruster?

Ion thruster has very low thrust due to its low mass flow rate. However is it possible to increase the mass flow rate? Together with its high exhaust velocity, won't the ion thruster be able to reach ...
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2answers
94 views

Rocket to slow freefall

I read that a human https://www.google.co.uk/search?client=ms-android-samsung&ei=l0_EWNjsHKXEgAafuIUg&q=john+stapp+45+g&oq=john+stapp+45&gs_l=mobile-gws-serp.1.0.0.6460.9902.0.10829....
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3answers
300 views

Small oxygen tanks

Does anyone know of any type of small, refillable oxygen tank. I'm trying to build a rocket and the smallest cylinder I could find is BernzOmatic's 1.4 oz. cylinder. A big cylinder isn't really safe ...
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1answer
7k views

Can a water-pump pump diesel?

After some research, I found that diesel is my choice of fuel. Now I need a way to pump it to the engine. My main constraint is price. So my question is can I use a water pump like one of these, to ...
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2answers
198 views

Propane rocket nozzle material

As far as I know, propane with oxygen will burn at 2800 °C and steel will melt at ~1500 °C. Brass is even less. What I am trying to do is a rocket nozzle. Is there a way I can built this with steel ...
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4answers
348 views

Are rocket engines practical for commercial aircraft?

What are the prospects of seeing rocket engines become the standard for commercial aircraft? It might be a dumb question; I really don't know all that much about the topic. The reason I ask is that ...