Questions tagged [engine-design]
Questions regarding the design or design process for a propulsion system.
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How "big" is a 2 megawatt preburner?
Reaction Engines recently announced a milestone completion in their SABRE development program:
we have tested the engine’s advanced hydrogen pre-burner at energy
delivery levels in excess of two ...
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A question about Nozzle/Extension/Skirt Size
In many rocket engines i see that the thrust chamber and a small part of the nozzle are one piece.
Does anyone knows if there's a formula which determines what portion of the nozzle is A ?
and how ...
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Does electric fuel pumping scale well for rockets?
The Electron launch vehicle first stage has nine Rutherford engines In addition to adapting the single-engine-out-friendly nine engine configuration from the Falcon-9, the rocket carries a significant ...
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How Intuitive Machines' engines "crank out unmatched performance in the space domain" allowing "transit of Van Allen belts once, unlike competitors"?
According to https://www.intuitivemachines.com/propulsion
LOX/Methane Engines
Our LOX/Methane engines are unique for in-space propulsion, in that they offer safety in handling and testing here on the ...
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What "unique control system" modulated GOCE's thrust to compensate for variable atmospheric drag? How did it know how to modulate it?
This answer to How much time did the longest maneuver last? says:
The GOCE satellite mission (Gravity Field and Steady-State Ocean Circulation Explorer) lasted 55 months (4.6 years) of largely ...
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Fan powered turbo-pump for low altitude/missile engines
There are many different liquid rocket engine power cycles, forxing propellant into the combustion chamber with tank pressurisation, gas generators, and heat exchangers, amongst others. Instead of ...
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Does anyone know the stay time, or what characteristic length should be used, for a LOX/LCH4-fuelled rocket engine?
Just what it says on the tin. I need to know either the "stay time" (Ts) or characteristic length (L*) that would be used to figure combustion chamber dimensions used with a LOX/LCH4-...
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Calculating total burn time for a rocket under constant acceleration with two propellant consumption rates
I tried posting this question on the Physics side of StackExchange but didn't get any response after a week, presumably because it was lost within the broadness of physics in general, so I'm hoping ...
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Does a cryogenic liquid propellant engine exist capable of using multiple fuels?
For example, a rocket engine which can use both liquid methane and liquid hydrogen.
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What makes CAPSTONE-1's eight hydrazine thrusters so "super small, high-performance"? How do they work without any tank pressurization?
The NASA Ames Feature Innovative Propulsion System Gets Ready to Help Study Moon Orbit for Artemis
says:
CAPSTONE’s journey to the Moon will take about three months, starting with its launch to low-...
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Making sense of rocket engine thrust calculation [closed]
Recently I've been trying to design a hypothetical rocket engine using the mass flow rate, exit mach, temperature, and pressure calculations provided by NASA's own website. I've come to know quite ...
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Tory Bruno mentioned "unsolvable combustion instability" of "large methane engines". What, why, how?
Relevant tweet, an hour ago: https://twitter.com/torybruno/status/1405210138189864960?s=19
a Tweeted Question: Why wasn't methane used in the 2000s, when it was readily available unlike the time ...
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If building a liquid propellant rocket engine, with bi propellants, how does the dimensions of my Combustion chamber, affect the efficiency?
If building a liquid propellant rocket engine, with bi propellants, how does the dimensions of my Combustion chamber, affect the efficiency ?
but also what is the best C* dimensions for an earth sea ...
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Designing a catalyst for use in catalytically hypergolic fuel mixtures using nitrous oxide
The use of hydrogen peroxide with hydrocarbons such as RP1 has long been a popular choice, not least of all for its hypergolic properties when paired with a catalyst bed. This motor design, catalysing ...
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What are the various ways that hybrid rocket engines are "turned on" or ignited?
I want to know the more complex side of hybrid rocket engines. I already know most of the basics like Newtons third law and oxidizer.
But I want to learn more of the complex stuff. I know they are &...
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Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios?
Question: Why can solid rockets be both the skinniest and most spherical launch vehicles while liquid fuel rockets have a more limited range of aspect ratios? Are there fundamental engineering ...
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Why did each F-1 engine have dual fuel feedlines?
Each F-1 engine had two fuel feedlines connecting it to the fuel tank as shown in these contemporary photographs and drawings.
The corresponding LOX system only had one feedline.
The engine had a ...
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What expansion ratio is the best for mars surface level engines?
What expansion ratio is the best for mars surface level engines?
For launches from Earth, first stage nozzles are much shorter than second stage nozzles because of Earth's high sea-level pressure. For ...
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What was the volume of the Rocketdyne F-1 engine's main combustion chamber?
In the specifications of the F-1 available online, I can find its dimensions, weight, thrust, etc. but I couldn't find what was the volume of its main combustion chamber. Is this information available?...
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How could I find the pressure and/or the Isp at the exit of a rocket nozzle if I have data for the throat and comb. chamber?
I've been looking at this for some time and working with CEA which will only give me data points for the pressure, temperature, Isp, etc. for the Injection, Combustion Chamber End, and the Throat; but ...
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Need help on rocket nozzle equation
I saw this earlier post about a guy who needed help with his equation, but I was wondering about how they got one of his numbers. They said that their foot-pound/pound/degree Rankine (the gas constant ...
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Pressurant gas line design considerations
I am trying to understand the constraints on pressurant gas line sizes and lengths.
For a static volume, the lines can be small in diameter because there is no significant flow velocity and therefore ...
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Injector design - LOX vs nitrous oxide
What will be the main design differences between using liquid oxygen and liquid nitrous oxide as oxidizer in a bi-propellant rocket engine? What liquid/gas properties (vapor pressure etc.) play the ...
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Open source liquid rocket engine
Is there an open source bi-propelant liquid rocket engine that would have all the documentation, computations, test results and 3D design files (CAD) freely accessible?
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Potential Fusion Drive system calculation issue
I will start off by saying that this is an entirely hypothetical drive system with plenty of handwaving and optimistic physics. My question I think is fairly simple and may just be something that ...
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How is the pressure within the gas generator determined?
The fact that pressure fed engines need their tanks to be at an even higher pressure has always confused me a little, but it's got me thinking; does the same logic apply to gas generator engines. If ...
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Is there a relation between combustion instabilities and chamber pressure?
Is there a relation between the combustion chamber pressure, and either an increase or decrease in both high and/or low frequency combustion instabilities. If so, how has this influenced engine design,...
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Cooling the nozzle extension of a nuclear salt water rocket (NSWR)
The nuclear salt water rocket(NSWR) uses a plutonium salt (at least to my understanding) dissolved in water as its fuel. The mixture is kept stable by filling the fuel tank with boron carbide, which ...
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ISP losses associated with exhaust vane TVC
What is the impact of exhaust vanes, such as those in the A4 and Redstone rockets, on exhaust velocity and overall ISP? As well as this, what is the relationship between ISP losses and the width of ...
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attitude thrusters sharing a common combustion chamber
Most smaller satellites and other larger but simpler space craft with a less demanding mass fraction tend to use cold gas thruster, importantly with a common or as few as possible pressure vessels, ...
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What were/are the stingiest and most generous vacuum nozzle? (records for the smallest and largest expansion ratios)
Vacuum nozzles are huge compared to their sea-level or atmospheric counterparts, as can be seen by comparing the first stage engines on an Electron or Falcon-9 to their second stages, where a big ...
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Are nuclear thermal engine designs limited to about twice the Isp of existing chemical rocket engines? If so, why; what's the limiting factor?
Discussion below With Ultra Safe Nuclear engines and hydrogen propellant, how far to Mars could you get and still be able to return to Earth in an emergency? including a comment that suggests that the ...
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Why are rocket engines shaped like a bell rather than a gun barrel? [duplicate]
When blasting matter out of a spacecraft engine for thrust, it seems like you'd want as much velocity in one direction as possible. Why do spacecraft engines (e.g., Apollo CSM) have big bell-shaped ...
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Rocket engine with lowest Isp to reach orbit
Which engine with the lowest possible specific impulse has reached orbit propelling a given rocket? There is a page at Wikipedia that compares orbital engines but some engines are missing Isp value ...
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Ultra Safe Nuclear Technologies (USNC-Tech) has delivered a design concept to NASA, but what does NASA consider a "design concept" to be?
The 19-Oct-2020 Press Release Ultra Safe Nuclear Technologies Delivers Advanced Nuclear Thermal Propulsion Design To NASA begins:
SEATTLE, Oct. 19, 2020 /PRNewswire/ -- Ultra Safe Nuclear ...
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How is gaseous fuel injected in Raptor engine's combustion chamber?
If liquid fuel and oxdizer is injected in a rocket combustion chamber, the mixture will be moving relatively slow before reaching the nozzle, preventing the flame front from escaping outside the ...
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Design impact on Chamber pressure
What is forming the amount of chamber pressure which is produced in a rocket engine and why would you like to have an higher chamber pressure?
I was calculating the SpaceX Raptor engine for myself, ...
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Is it always one nozzle per combustion chamber and one combustion chamber per nozzle?
When I read about engines like the RD-170 they might have a single turbopump feeding multiple combustion chambers, and each combustion chamber has its own nozzle. Is there, or would it be reasonable ...
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What is the practicality of using sub-cooled propane in combination with HTP in an amateur engine design? [closed]
Using sub-cooled propane, at approximately -90°C (b.p. -42°C at STP) in combination with >80% hydrogen peroxide, can any meaningful gains be made, whilst considering that this fuel mixture would be ...
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What is a "Major Component Failure" referred to in news reports about the unsuccessful Space Launch System core stage test firing?
In reporting about the unsuccessful green run of the SLS core stage, Ars Technica mentions
About 50 seconds into what was supposed to be an 8-minute test firing, the flight control center called out, ...
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Is there a distinct flame-front in a liquid-fuelled rocket combustion chamber?
Liquid fuel and liquid oxidizer are injected at high pressure through small orifices into the 'top' of a rocket's combustion chamber. The intention is that these mix quickly and then burn completely ...
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How important is the convergence angle of a liquid bipropellant rocket engine
So I can't exactly find out what angle should the converging part of the rocket chamber be or why different angles are chosen for engines (varies by about 15°).
Are there any guidlines on the angle or ...
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How does one determine the optimal CH4:O2 ratio in a methane-LOX rocket engine?
The SpaceX Raptor uses a 78:22 O2:CH4 ratio.
It also has combustion chamber pressures higher than any other rocket engine ever built.
My questions are:
What's the math / chemistry that determines ...
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Liquid Nitrogen Diluted Rocket
Imagine a rocket that uses a mixture of liquid nitrogen and oxygen as the oxidiser.
It is designed like an oxidiser-rich staged-combustion engine, however there is so much nitrogen in the mixture that ...
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Can liquid rocket engines have the same thrust as solid rocket engines?
Take the Vega rocket launcher for example. Its first three stages are solid rocket engines and burn at a relatively short time. If I were to change its first stage into a liquid rocket engine, can ...
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Where would one find information on the fuel properties (temp, max ISP) of non-conventional rocket fuels?
Yesterday's Starship landing saw at least one Raptor burning copper. Given that copper oxidizes with oxygen at the temperatures and pressures found in a Raptor combustion chamber, what properties does ...
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What happened to continuously-applied heat barrier coatings in engines?
In Ignition, Clark describes an interesting approach to thermal control in rocket engines using oxygen as an oxidizer and hydrocarbon fuel: A small amount (few percent) of silicone oil or another ...
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Using nuclear detonations for propulsion
The proposed orion propulsion system used nuclear explosions to push against a giant shock absorber and propell it, but from my understanding, nuclear explosions only produce heat and rely on the ...
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Will you be having rubber or wax with your peroxide? (hybrid engine fuel tradeoffs)
Hybrid engines offer some practical advantages and some budgetary ones that can offset lower ISP, including potentially safer solid fuel to store and non cryogenic storage of some oxidizers like ...
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Do pulse detonation rocket engines require any type of nozzle?
Rocket nozzles are used to convert slow moving gas under high pressure and temperature into hypersonic gas under approximately ambient pressure. From many videos of experimental Pulse Detonation ...
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