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Questions tagged [engine-design]

Questions regarding the design or design process for a propulsion system.

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12
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2answers
1k views

Did the Apollo F-1 engines gain weight during flight?

I was browsing through Wikipedia when I came across this infographic on the Rocketdyne F-1. It gives the engine dry weight as 18,500 pounds, and the engine burnout weight as 20,180 pounds, meaning the ...
16
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3answers
922 views

Pumped propellant propulsion - is it viable?

A recent article on Slashdot got me thinking. While the article is about using electric turbopumps for moving fuel from tanks to engines during launch phase and is just a small, incremental ...
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3answers
614 views

Could the Bloodhound Rocket Car be launched into orbit?

The Bloodhound SSC (Supersonic Car) currently being constructed to break the 1000 mph barrier is powered by a Hybrid Rocket (Solid fuel + HTP) and a Rolls-Royce EJ2000 Jet Engine: Considering the ...
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7answers
10k views

Can ion thrusters be scaled up?

All ion thrusters are quite small. Having read through the more approachable information about them, as they use physics pretty beyond me, I don't understand what it is about them that makes it ...
14
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1answer
1k views

Is there any rule for rocket engine nozzle proximity from each other?

I wonder if there is any rule for how closely you can put engine nozzles to each other. Are there any vibration, heat, etc. constraints when you are assembling two or more engine bells together? ...
9
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1answer
179 views

Do modern CFD codes reduce the number of test firings in an engine program?

Given the complexity of liquid propellant rocket engine development, I wonder if (and how much) modern Computational Fluid Dynamics (CFD) codes help to reduce overall development costs. Do they ...
26
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3answers
7k views

Why doesn't the US use European rocket engines?

US Companies have been using Russian rocket engines for their rockets for a long time, even during sanctions. But as I was going through the European rocket launches, I felt European rocket engines ...
14
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1answer
2k views

What NASA documents did SpaceX use to design their engines?

I've watched this (excellent) panel discussion titled 'Our Future in Space'. Bill Nye says at 22:48 that SpaceX got their engine design from work done by NASA, which they developed into a working ...
4
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1answer
2k views

How to seal the connection between the combustion chamber and outer shell in this rocket engine model?

Here is rocket engine drawing. The combustion chamber made from copper and the outer shell from stainless steel. The coolant, either water or gasoline will be between With either pressurised water or ...
9
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1answer
2k views

Practical limits to a restarting a main rocket engine in orbit? [duplicate]

With current technologies, are there practical limits on the number of times a rocket engine can be restarted while still remaining in orbit? Given sufficient fuel, could an engine be designed today ...
16
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1answer
9k views

Why is the Russian approach to the aerodynamics of their rockets different?

Russian rockets look like this: They flare them out at the bottom. With their newest rocket, the Proton, the flared shape is gone but the boosters still have caps that angle in towards the main ...
6
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3answers
1k views

What sort of analysis was performed before “modern” computing and the invention of finite element analysis and computational fluid dynamics?

I am not sure if this question is appropriate for this SE - Ideally this should be posted in Engineering SE but as far as I'm aware it does not exist! (I can only assume that the scope of engineering ...
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2answers
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Disposition of the Oxidizer Tank in Rockets with Autogenous Pressurization

A little while ago, Ars Technica did a big story on the Firefly rocket under development. http://arstechnica.com/science/2014/11/firefly-space-systems-charges-full-speed-toward-low-earth-orbit/2/ A ...
11
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2answers
1k views

How will the SLS first stage be supplied with engines? Copy manufacturing the RS-25 or replacing it?

The SLS is a very opinionated subject among bloggers. I'm looking for what substance there might be behind the following general claim (without specific source). Is it truthful and if so, what is the ...
37
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3answers
11k views

Why are rocket engines operating above 100% often considered nominal?

It was brought to the attention of the community that right before the crash of Antares the commentator noted: "Main engines at 108%" It was noted that other engines were also reported to work at ...
9
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1answer
1k views

What was the first rocket to use gimbaled thrust?

A gimbaled thrust system was used on the Space Shuttle, which is easily recognized in the beginning of this launch video. Was this technology first used by jet fighters, or was it first invented for ...
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0answers
272 views

Pintle injector in a Vortex Cooled Chamber Wall (VCCW) Engine

All the articles I have found show the VCCW engines using flat plate injectors. With the inherent combustion stability of a Pintle injector system, it would seem to be a better choice, yet I find no ...
12
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2answers
2k views

Quality vs. Quantity for Rocket Engines

I read a while ago about the famous Soviet N-1, called by some the most powerful rocket (in terms of thrust at liftoff) in history. It used an incredible 30 engines in its first stage. The American ...
9
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3answers
6k views

How does liquified natural gas compare to liquid methane?

So ULA and Blue Origin have announced they are designing a LOX/LNG rocket engine (link). From what I understand, LNG is just a less pure form of methane (CH4). Is this correct? Why are they ...
3
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1answer
332 views

ISRO's Mars Orbiter Mission - LAM vs Attitude thrusters reliability

ISRO expressed concerns on restarting the Liquid Apogee Motor (LAM) for Mars Orbit Insertion (MOI) after a long coasting period of its Mars Orbiter Mission (MOM). ISRO has redesigned the LAM plumbing ...
17
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1answer
2k views

Why the non-symmetric design of rocket nozzles?

Although I have seen many perfectly symmetric nozzles, I have also seen designs such as this (Virgin Galactic) which is only symmetrical about one axis: Why is this?
6
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1answer
2k views

Does the Falcon 9 v1.1 form a shock diamond when in flight?

How does the Falcon 9 v1.1 form this exhaust pattern with its nine Merlin 1D engines? Is it a bigger, rougher shock diamond? I am trying to learn more about how one could form with a cluster of ...
13
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4answers
2k views

What are the consequences of NASA validating this “impossible” space drive?

A British inventor invented an engine that can provide thrust in outer space without a propellant. This engine has been tested by a Chinese team, and more recently by NASA: The engine itself is The ...
20
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4answers
760 views

Could a rocket engine be designed to use different fuels? (Like LOX+H2, LOX+CH4)

I'm obviously not a rocket scientist, so this might rank among the stoopidest questions around here. I wonder if it is feasible to design a rocket engine which could be reused in space by refilling it ...
10
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2answers
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Dangers of launching a nuclear thermal rocket

Nuclear thermal rockets may have great benefits for Solar system exploration. But one consideration is that the launch of a nuclear engine from Earth's surface, as the payload on a chemical rocket, ...
10
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4answers
3k views

How does a thin metal rocket engine not get crushed by the weight of the flying rocket?

It looks like a liquid fuel rocket engine is made of rather thin metal. Here's photo of RD-107 from Wikipedia Nothing personal, but it looks like it's made of several shiny thin metal cans (connected ...
7
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1answer
419 views

Have the micronewton thrusters developed for the LISA mission been flight tested yet?

JPL together with Goddard and a private company called Busek Company Inc. developed a new type of propulsion system known as micronewton thrusters for the LISA mission (which has since had a name ...
12
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2answers
3k views

Why the huge thrust difference between a Sea level and Vacuum J-2 engine?

Looking at the Wikipedia page for the J-2 (one engine was used on the Saturn V third stage, and 5 engines on the second stage) it gets about 232Klbs thrust in vacuum, but at sea level, only 109KLbs ...
10
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2answers
623 views

Can a booster be designed to withstand 10,000 Gs?

In Could any existing gun reach the Karman Line?, Richard Graf's Kickstarter campaign for his Starfire space-gun is referenced & discussed. Setting aside my native skepticism for a project with ...
8
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1answer
1k views

Is there a diagram of different nozzle diameters to scale?

I am looking for a diagram that shows the different diameters of various nozzle openings, including Rocketdyne's F1 (150 inches) SpaceX's Merlin (66 inches), the Air Force's Delta IV Heavy, and NPO ...
67
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10answers
43k views

Why is SpaceX considering Methane as fuel for their next engine, the Raptor?

Currently, SpaceX has developed the Merlin 1 family (1B (Falcon 1), 1C (Falcon 9 v1.0), 1D (Falcon 9 v1.1/F9-R/Falcon Heavy), vacuum versions and sealevel versions) which are LOX/RP1 based. (75-...
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7answers
15k views

Why aren't linear aerospike engines in common use?

Linear aerospike engines are an old idea that seem so full of promise. Why are they not widely used today by the likes of Boeing, SpaceX, etc.?
7
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3answers
2k views

How does a launch vehicle control its trajectory during the first stage?

It appears during most launches that the only engines working are the main first stage engines. It was my understanding that these engines are fixed in place and cannot turn the rocket, but I must be ...
21
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2answers
3k views

Are nuclear-powered engines the way to go for space exploration?

I often think about the future of humanity and how to achieve it. Despite criticism, the USA and USSR achieved significant scientific breakthroughs, such as: putting the first man in space landing ...
12
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1answer
2k views

Why was the Apollo CM main engine thought to be unreliable on Apollo 13?

When Apollo 13 had most of its internal systems destroyed by an explosion, NASA decided that the best course of action would be to fire the main engine on the dark side of the moon to send the capsule ...
13
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5answers
4k views

Can a rocket motor be shut off after ignition?

After ignition, if any problems occur such as fuel leakage, can a rocket motor can be shut off?
13
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1answer
2k views

Are MMH and UDMH interchangeable?

Can Monomethylhydrazine and Unsymmetrical dimethylhydrazine be used one in place of another for the class of the existing orbital maneuver engines (with reduced performance may be)? Such as Shuttle's ...
13
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2answers
16k views

Efficient types of nozzles used in rockets

Is there any other type of nozzle other than common convergent-divergent nozzle (see picture below) which is used in many rockets?             ...
14
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1answer
2k views

Changes made to ISRO GSLV-D5's CUS and FBTP since GSLV-D3's LH2/LOX CUS failure to sustain ignition?

The launch of the ISRO GSLV-D5 launching India's GSAT 14 advanced communications satellite (weighing 1,980 kg) is slated for 19th of August, 2013, flying in the GSLV Mk.2 configuration with an Indian-...
10
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2answers
994 views

Why was the NERVA program dropped?

At the very end, NERVA (Nuclear Engine for Rocket Vehicle Application) had developed nearly flight-ready engines able to: operate for periods in excess of an hour while providing maximum thrusts up ...
8
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1answer
360 views

Any other countries/companies doing anything similar to British Skylon SSTO?

I was reading about the British Skylon SSTO (Single Stage To Orbit) vehicle and its SABRE engine described in Wikipedia. The engine technology looks remarkable, if not revolutionary. Is this a unique ...
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2answers
3k views

Why do pressure fed engines have combustion instabilities?

Reading about the Sea Dragon idea, I came upon this argument against it, which sounds compelling, but relies on more detailed knowledge than I have: Those are to be pressure-fed to avoid "...
14
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1answer
722 views

At what travel distances are ion engines faster and more efficient than conventional fuel engines?

According to Scientific American (February 2009), ion engines start off slow, but build up speed as they travel. At what travel distance would an ion engine (such as an ion thruster, a Hall thruster, ...