Questions tagged [engine-design]

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

Filter by
Sorted by
Tagged with
12
votes
1answer
914 views

Viking Lander descent engine design feature

The Viking Lander Terminal Descent Engine (3 per vehicle) was a ~600 lbf monopropellant hydrazine engine with an unusual exhaust system of 18 small nozzles. Multiple sources state that the reason ...
2
votes
0answers
24 views

Where could I find more propellant combustion charts for more different/more broad examples/numbers?

So after asking how I could calculate this kind of propellant combustion charts for different fuels/oxidizers and other ratios and other stuff and getting some really good answers, especially from ...
9
votes
3answers
2k views

Why are stages not connected by the engine nozzle? Why are interstages used?

First, a clarification: I understand the aerodynamic reasons that interstages are used, and I understand that the shockwaves that would be generated without an interstage would wreck the rocket. My ...
22
votes
2answers
6k views

If rocket engines only need fuel and oxidizer, then why there are so many pipe lines on the engines?

If fuel and oxidizer are pumped by turbines to the combustion chamber, then why there are so many pipes around? It should only have a two-cylinder shaped turbine assembly. I doubt there are other ...
7
votes
1answer
146 views

Which are good resources to learn more about the components of a rocket engine?

A detailed and annotated image of a SpaceX raptor engine (found on a SpaceX website) illustrates that in addition to the major components (e.g. pumps, inlets, combustion chamber, nozzle), there are ...
10
votes
2answers
4k views

Is the concept of the Epstein Drive based on actual theorized scientific research which is considered plausable?

I've always found it interesting when we see real life taking its cues from fictional arts, especially when it comes to Science Fiction technology. There are plenty of examples of classic books, TV ...
3
votes
3answers
192 views

What (if anything) limits the efficiency of a rocket engine?

Humans have developed lots of rockets. I observe that in most cases to increase the payload capacity we just increase the amount of fuel. Is it not possible to exponentially increase the efficiency ...
3
votes
2answers
90 views

How to calculate these engine parameters on my own?

I am a space enthusiast and am intrigued mostly by rockets. I recently found a book HOW to DESIGN, BUILD and TEST SMALL LIQUID-FUEL ROCKET ENGINES and have been fiddling around with rocket engine ...
3
votes
0answers
37 views

Storage density of a Deuterium-Helium 3 fusion pellet

in a series I am working on I will be using a D-He3 fusion drive system (similar to the one in the expanse according to Project RHO). I am under the assumption that the fuel will be stored in a pellet ...
0
votes
1answer
64 views

Pressure withstanding capability

As you can see in this pic, F-1 rocket engine consists of 15 main components. Now, how is it possible to keep all the components together intact in high pressure situations like when the rocket is in ...
11
votes
1answer
660 views

Why does the core stage of the Ariane 5 produce more thrust in vacuum?

In listening to a youtube video that was discussing the Ariane 5, the narrator noted briefly in passing that the Vulcain 2 engine produced more power thrust in a vacuum than it did at sea level. Not ...
16
votes
1answer
1k views

What is an “exhausterator” and what does it do?

I laughed when I first saw the word "exhausterator" mentioned, I scratched my head when I saw it the second time, and I came here after the third. Besides making me feel like maybe technobabble isn't ...
4
votes
2answers
276 views

How do spherical SRB's compare to long skinny ones? What do their thrust curves look like?

Most SRBs are long and skinny, probably because most are used low in Earth's atmosphere where aerodynamic drag is large. But here are some very short SRBs, one seemingly spherical except for the ...
0
votes
0answers
94 views

Why was circa 600 volts used for DAWN's ion propulsion?

This answer estimates that the DAWN spacecraft's solar-electric propulsion accelerated about 3 milligrams of Xe+1 per second, using roughly 1350 Watts of electrical power. I estimate that 3 mg/sec of ...
6
votes
1answer
143 views

What is the thickness of a rocket nozzle?

For a university project, I'm working on optimisation of a Falcon-9-like launch vehicle, and one element of that is varying expansion ratios of the engines. This will impact on the engine mass, but to ...
0
votes
1answer
67 views

Calculations needed to full-design a rocket

Suppose I want to put a cubesat in Titan's orbit (saturn's moon). and I want to calculate what rocket power I need, how do I calculate it? Where do I begin? total mass of the probe or delta-v needed? ...
2
votes
1answer
45 views

Are regneratively cooled nozzles still modeled as isentropic flow?

In a regeneratively cooled nozzle, there is a transfer of heat from the expanding exhaust to the nozzle (and then into the propellant cooling the nozzle). This is clearly not an adiabatic process. Is ...
2
votes
0answers
47 views

What is the load path for thrust in a rocket engine? [duplicate]

This may be a duplicate of this question but I wasn't sure if I could hijack that one to clarify or regenerate interest there. What is the distribution of axial force in a combustion chamber? My ...
4
votes
1answer
184 views

Why were later Russian engines inferior to the NK-33?

In terms of thrust-to-weight ratio the NK-33 engine developed for the Soviet N-1 rocket was by far the best in the world at the time, with a thrust-to-weight ratio of 137. But subsequent Russian ...
2
votes
0answers
134 views

Would this 'hybrid expander cycle' engine be practical?

This is another attempt at making closed expander cycle a bit more efficient (the first attempt was here). The design combines some elements of both the open and the closed expander cycles (hence the "...
4
votes
1answer
149 views

Saturn V and Atlas Engines exhaust issues

This is a follow up question to "Organic Marbles" answer to my earlier question about the atlas rocket exhaust nozzle, regarding the Apollo F1 thrust nozzles having metal baffles/fins inside to ...
9
votes
1answer
821 views

Atlas Rocket Burning Hose

I was just watching The Right Stuff for the 100th time,and I've always wondered what is that hose spewing flame/burning propellant out of the bottom of the rocket. It's definitely not an engine,and ...
3
votes
1answer
178 views

Why is ESA developing the Vinci engine rather than buying RL10Bs?

The Vinci engine seems very very similar to the RL10B. Both are hydrolox expander-cycle engines with 465 s Isp and extendible nozzles with a ~250:1 expansion ratio. The biggest difference is that the ...
5
votes
1answer
254 views

Is there anything fundamentally wrong with 'autogenous expander cycle`?

This question is a spinoff from here. To set the context, here is my understanding of the expander cycle: Closed expander cycle is very efficient, perhaps more efficient than staged combustion cycle....
14
votes
1answer
796 views

Why aren't expander cycle engines used on lower stages?

Looking at the simplicity of BE-7, I was wondering why dual closed expander cycle engines are not used more commonly and, as far as I know, are not used as lower stage engines at all. A commonly ...
9
votes
2answers
566 views

As of January 2020, what is the single longest duration firing executed with a Raptor engine?

Can someone cut through the woo for me? As of January 2020, what is the single longest duration firing executed with a Raptor engine? Have any successfully run for full mission duration? Sourced ...
4
votes
1answer
263 views

What percent of fuel is consumed in powering the turbopumps? [closed]

The RD-170 consumes 5,300 lbs of fuel per second, including oxidizer. The turbopump produces 230,000 hp. If one assumes that roughly 1 lb of fuel is required to generate 1 lb of thrust (obviously this ...
0
votes
0answers
142 views

How do toroidal and linear aerospike nozzles compare?

What are the pro's and con's of toroidal and linear aerospike engines with respect to each other? When does one choose one design over the other? A linear aerospike is characterized by multiple ...
3
votes
1answer
227 views

Why did the Agena-D leak oxidiser when starting its engine?

The Agena-D upper stage, although extremely reliable, had a tendency to leak some of its RFNA oxidiser when starting its Bell 8096 engine; although not a problem for a stock Agena-D, it did cause ...
0
votes
2answers
240 views

Why was the reusability of the SSMEs so poor, and why was this considered acceptable given their purpose to launch a reusable vehicle?

The Space Shuttle Main Engines operated for around 8.5 minutes in every Shuttle launch, yet were removed from the orbiter after each flight and went through an overhaul, parts often being traded from ...
0
votes
1answer
133 views

What is a typical sea-level engine nozzle/expansion ratio? What about vacuum engines?

On a sea-Level engine, what is the average nozzle ratio? What about an upper-stage vacuum engine?
2
votes
0answers
61 views

Deep throttling in sea level engines

In this excellent answer, asked for merlin engines deep throttling in first stage and produced here. To help you understand where the cross over point is, here is some math for understanding the ...
1
vote
1answer
57 views

Why would the ideal mass flow rate be less than that of real life?

Comparing the mass flow rate at the throat using the below theory, I find that the mass flow rate isn't accurate but isn't always larger than that of the engine specs (ideal assumptions ). What ...
2
votes
1answer
144 views

Why did Virgin Galactic decide to use a hybrid engine vs liquid on their space ship?

To me, it seems like their business case is very dependent on rapid reuse. With this in mind, using a hybrid engine that would need to be replaced every flight seems very counter intuitive vs a liquid ...
4
votes
1answer
151 views

Why does the RL10 engine have a pipe sticking out of the side on the Centaur rocket?

The RL10 is a expander cycle engine so the pipe can’t be for a gas generator.
1
vote
2answers
103 views

Is the RD0146 an open or closed cycle engine?

RD0146 has been in the latest family of engines being developed from both Russia and US(Pratt and whitney). However, there is a lack of clarity in estabishing whether the expander cycle engine is open ...
2
votes
0answers
48 views

Are there any staged combustion cycle rocket engines under 1000 kN? Is it easier to produce larger engines with this type of engine cycle?

I found that most engines developed with staged combustion cycles are inherently quite powerful. Are there any engines which was developed with the staged combustion cycle with a thrust under 1 MN. ...
4
votes
0answers
80 views

Maximum speed of rocket propellant flow?

In reading this question (Limiting factors of liquid rocket engine thrust), it prompts me to ask if there is an upper limit in how fast the propellant/oxidizer can be pumped into a combustion chamber ...
2
votes
1answer
109 views

Is it possible for one to adapt engine data for different fuels wrt liquid rocket engines

Liquid Rocket engine design is quite complicated and idealised and assumed theories rarely get sufficient validation. In an effort to verify/validate newer/untested fuels to be used in engine designs, ...
0
votes
1answer
63 views

What impacts do the rocket engine cycles have on the sizing of the components and effectively the engine?

For a given performance requirement, combustion pressure, propellant mixture, etc. How can one vary between the various engine power cycles such as gas generator, staged combustion, expander, and how ...
1
vote
1answer
109 views

What parameters drive the development effort and cost of a liquid rocket engine for orbital launchers(LEO - GEO)?

The development cost for a rocket engine drives the cost for a launcher and can be attributed to some basic parameters Apart from the few below, what others may be critical to developing and designing ...
8
votes
2answers
309 views

Do any rocket engines besides the F1 need/require baffles?

The F1 engine required baffles on the injector plate to control combustion instabilities so that it wouldn't blow itself up. Was that unique? Or do other engines also have baffles for the same reason? ...
5
votes
1answer
203 views

What are some of the important parameters to scaling a liquid rocket engine

Liquid Rocket Engines can be clustered together on a stage but their performance, weight and size largely decide and constrain the design of the launcher. Data on the newer smaller launcher engines ...
-4
votes
1answer
210 views

Magnetic force-driven propulsion system for an interplanetary/interstellar spacecraft

I have come up with a conceptual idea of a magnetic force-driven space propulsion system. What I believe is very unique about this propulsion system concept is that its working principle should not ...
1
vote
1answer
193 views

Kerosene engine film cooling

So it is clear that kerosene fueled engines use two fluids for film cooling via injection in the combustion chamber, throat, or nozzle. (That is "true film cooling" and not just a fuel rich outer ring ...
2
votes
2answers
231 views

Saturn I's four outer engines' gas generator exhaust, why not vent to the side like the four inner engines?

At about 04:58 in Scott Manley's new video NASA Might Be Giving Away A Saturn I Rocket - Here's Why I Love This Vintage Booster he says: So the four engines in the ...
1
vote
2answers
184 views

Whats the difference between cryogenic and cryo storable rocket engines

I've read about cryogenic storable liquid rocket engine but since it doesn't refer to its fuel, I want to understand the difference between a cryogenic and a cryo-storable engine. The term cryo-...
2
votes
2answers
132 views

Is it possible to use hybrid propulsion to drive the turbopump?

Turbopump are driven either by a preburner or by an electrical engine (OK this technology is quite new and currently in 2019 only used on the Rutherford engine). If I understand correctly, using ...
4
votes
1answer
485 views

Why can't an expander-cycle engine be built to use RP-1 or other non-cryogenic fuels?

The expander cycle family of rocket-engine power cycles involve using waste heat from the engine's combustion chamber and/or nozzle to vapourise some or all of the engine's fuel, and using the now-...
0
votes
1answer
72 views

Could LNG fuel be used to pressure feed itself into combustion chamber?

In pressure fed cycle a high pressure gas tank contents are exhausted into the fuel and oxidizer tanks to essentially push them into the combustion chamber. Could a portion of the fuel from an LNG ...

1
2 3 4 5 6