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Questions tagged [engine-design]

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

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RL10 Injector Plate

Could anyone enlighten me with this puzzle ? The following frames are screenshots from an P&W RL10 engine's video. It's actually the top view of Fuel Injector Manifold and the LOX/Injector Domes (?...
user3184199's user avatar
5 votes
1 answer
163 views

How does a liquid rocket engine prevent the combustion from going back in? [duplicate]

To my knowledge, the liquid engines usually utilize a turbopump to gush fuel into the combustion chamber. Later that fuel is mixed and injected in a mist form through the injector to be ignited. ...
Aerospace_Nerd's user avatar
7 votes
1 answer
2k views

What is the maximum number of times a liquid rocket engine has detonated/ exploded during development?

My question comes from a lot of research and curiosity. Do they stop the development process at 10-20 detonations/ explosions? Or do they keep continuining solving one problem after the other. Modern ...
Karthikumar Sambasivam's user avatar
1 vote
1 answer
170 views

Why should nozzles be perfectly expanded?

If I understand it correctly, the only problem with an overexpanded nozzle is (aside from technical difficulties) that the surrounding atmosphere puts pressure on the exhaust gases and reduces engine ...
Saturn V's user avatar
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1 vote
0 answers
236 views

Really weird engine nozzle design

This Martin design for an Single Stage To Orbit orbital satellite Launch Vehicle was part of the High Altitude Test Vehicle (HATV) program. Credit: © Mark Wade http://www.astronautix.com/m/martinhatv....
AnarchoEngineer's user avatar
2 votes
1 answer
128 views

Choice of Ammonia and oxygen as liquid rocket propellants in vortex combustion

I have been thinking lately about the benefits of using liquid ammonia and oxygen as rocket propellants, where ammonia is difficult to burn, what if in a fuel rich closed cycle, ammonia is used to ...
kent nelson's user avatar
4 votes
1 answer
121 views

Solar Reflective Plasma Drive

I understand that solar sails have just recently been progressing to be of use. Could the solar sails be positioned to create a hyperbolic mirror to super heat a substance to produce propulsion along ...
Justintimeforfun's user avatar
2 votes
0 answers
49 views

How to calculate the cooling jacket of a liquid propellant engine with an external component? [closed]

When designing a small rocket engine with a thrust of 100 N, questions arose about the cooling of the combustion chamber and the nozzle apparatus. It was decided to ...
DYNAMIC AEROSPACE's user avatar
3 votes
0 answers
143 views

Atlas V RD-180 Analysis

I was tasked with researching certain properties of the RD-180 engine. I am finding contradictory information, or I am unable to find it at all. I am looking for the following information Mixture ...
PilotGeometer's user avatar
1 vote
0 answers
52 views

Combustion chamber pressure calculation [duplicate]

A liquid propellent rocket engine: how is combustion chamber pressure calculated? Is it the different between turbopump outlet pressure and the drop in the injectors (losses aside)? Thanks!
Mariner's user avatar
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2 votes
0 answers
87 views

Would (Dual Concentric inline Powerhead) FFSC Cycle engine be possible to engineer

I,ve been wondering if it was possible engineer and how we would we work it out DUAL preburner inline FFSCC ENGINE with concentric core and individual concentric turbine inside one another and maybe ...
ALPHA GENISIS XTREMED's user avatar
3 votes
1 answer
209 views

RS-25 Component weight

I need to determine the weight for specific components of the RS-25 Rocket engine. Namely the combustion chamber and nozzle separate from all other engine components? I must have found hundreds of ...
Slartibartfast's user avatar
3 votes
2 answers
647 views

Fueling the RS-25 Turbo pumps?

Is there any way to know the weight of Fuel / Oxidizer consumed by just the turbo pumps of the RS-25 rocket engine?
Slartibartfast's user avatar
1 vote
1 answer
141 views

Question on improved SSME thrust chamber construction

How do you get the closed out copper liner of the thrust chamber, which is hour glass shaped, into a jacket that is also the exact same shape like shown? I'm gonna guess it was done by diffusion ...
Meatball Princess's user avatar
0 votes
0 answers
98 views

Can coking be avoided by pumping fuel after shutdown?

As I understand it, coking in kerolox engines occurs when the engine shuts down and fuel flow stops, causing fuel still in the coolant channels to overheat and decompose. Can this problem.be avoided ...
Abdullah is not an Amalekite's user avatar
1 vote
0 answers
120 views

Does an overexpanded nozzle behave like a suction cup?

It is generally said that, to obtain optimal specific impulse, a nozzle should be just the right size that the exhaust pressure is equal to the ambient pressure. Quoting this answer, a relevant ...
Charles Staats's user avatar
3 votes
0 answers
148 views

What are the major tradeoffs for a launch vehicle having either one 400 kN engine or eight 50 kN engines?

Given the problem of choosing to build and launch a small rocket to put a smallsat into orbit with either of these two configurations, what are the major tradeoffs between them? For specific issues ...
Muhammad Ahsan's user avatar
2 votes
0 answers
143 views

What was the exhaust pressure of the Saturn V? [duplicate]

I am trying to write some code to simulate rocket launches, and I am doing a proof of concept using the Apollo 11 as a model, to fill my values. When calculating thrust I am using the equation: F=m⋅Ve+...
owinius's user avatar
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0 answers
46 views

How to calculate the tank boost system for the displacement feed system?

There is a liquid rocket engine running on two components: highly concentrated hydrogen peroxide and kerosene, fuel vapor is ...
Андрей Александров's user avatar
2 votes
1 answer
102 views

Combustion stability for the second stage of Sea Dragon

I was listening to a video about SHLV's (Super Heavy Launch Vehicles), and Sea Dragon's first stage engine was mentioned. In terms of combustions stability, the suggested fix would be large combustion ...
AnarchoEngineer's user avatar
1 vote
0 answers
54 views

Rough values for the staytime or characteristic length of the combustion chamber of an oxygen/methanol rocket engine?

I'd like to have some idea of the staytime or characteristic length of the combustion chamber of an oxygen/methanol rocket engine. Are there sources for this, or a way to estimate it? I've tried, but ...
Kevin's user avatar
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2 votes
0 answers
145 views

Contraction Ratio Impact on Performance for Liquid Rocket Engine

How does one go about calculating the necessary contraction ratio (combustion chamber/nozzle throat cross sectional areas) of an engine with these parameters known... thrust nozzle throat area mass ...
Frahanco Deressa's user avatar
1 vote
1 answer
102 views

Multi-stage combustion products?

Okay so I've never seen anything about this before, and that's probably for a very obvious, very simple reason I am far too dim to think of, but here goes: Most combustion reactions in rocket chambers ...
AnarchoEngineer's user avatar
1 vote
0 answers
183 views

How to find the correct size and angle for a conical nozzle on a rocket engine? [closed]

So I need to know the equations for finding the size and angle for a conical nozzle. I am making a rocket engine and I decided the conical nozzle would be the easiest to build. The rocket is going to ...
Anish Kommireddy's user avatar
6 votes
0 answers
236 views

How do spacecraft protect their engines from micrometeroids?

A meteoroid impact on an engine bell can easily rupture a coolant pipe. Or it can create an imperfection in the backing plate from where cracks can form. Or it can destroy an injector. All of these ...
Abdullah is not an Amalekite's user avatar
0 votes
0 answers
110 views

SSME/RS-25:; Why arent high pressure and low pressure pumps coaxial?

The Space Shuttle Main Engine low pressure pumps to prevent cavitation at the main pumps. This pumps were driven by separate turbines fed by high pressure fluid from the main pumps. Why? It just adds ...
Abdullah is not an Amalekite's user avatar
4 votes
1 answer
785 views

SSME/RS-25: why seal between LOX pump and preburner?

Both the the fuel and oxidiser preburners ran fuel rich. In order to prevent the preburner gas from entering the LOX pump and blowing it up, they had this complex double seal with a gas purged void in ...
Abdullah is not an Amalekite's user avatar
3 votes
1 answer
344 views

Why will the Raptor not face the same turnaround issues as Space Shuttle engines?

The RS-25's notoriously slow, expensive turnaround was blamed on its complexity. The Raptor appears about as complex. Both use regenerative cooling. Both use preburners to drive turbopumps. While the ...
Abdullah is not an Amalekite's user avatar
0 votes
1 answer
119 views

How does SpaceX Raptor deliver a more benign turbine environment?

Raptor has been claimed to be able to deliver "long life ... and more benign turbine environments". https://en.wikipedia.org/wiki/SpaceX_Raptor The Raptor has hot oxygen flowing out of the ...
Abdullah is not an Amalekite's user avatar
7 votes
2 answers
709 views

Does methalox fuel have a coking problem at all?

Methane was chosen for SpaceX Raptor because it has less coking problem that kerosene. But does it completely eliminate it? If not, how much less severe is it? I googled 'thermal decomposition of ...
Abdullah is not an Amalekite's user avatar
1 vote
1 answer
238 views

Can a spinning water film cool an engine cheaper and better than ablative?

Ablative cooling us an incredibly simple way to cool a liquid rocket engine, when compared to regenerative cooling. But ablatively cooled engines are (presumably) hard to refurbish. Why not inject a ...
Abdullah is not an Amalekite's user avatar
2 votes
0 answers
107 views

Do smaller engines have a higher thrust to weight ratio?

For a given chamber pressure and shape, thrust is proportional to nozzle area, which is proportional to the square of dimensions mass is proportional to the volume, which is proportional to the cube ...
Abdullah is not an Amalekite's user avatar
4 votes
1 answer
1k views

Why do the Titan SRBs have an angled engine bell?

Looking at pictures of Titan rockets with solid rocket boosters, the bell is at an angle. Why would they do that? https://historicspacecraft.com/Rockets_Titan.html https://en.wikipedia.org/wiki/...
Blue Skin and Glowing Red Eyes's user avatar
3 votes
0 answers
66 views

Recent GPS III Launch Intended or Unplanned Venting?

Between 14:01 and 14:14 in the following video, there is a significant gas vent happening behind the engine bell: Is this working as intended, or does that appear to ...
HumanJHawkins's user avatar
0 votes
0 answers
58 views

What is a bimodal or multimodal space rocket engine? Especially a nuclear-powered one?

I can't seem to find a specific answer anywhere.... I wonder if it means using the radioactive fuel to power the electronic equipment, purely via natural decay, but also using the same fuel to power a ...
Kurt Hikes's user avatar
37 votes
4 answers
9k views

Why did the Soviet Union decide to use 30 small engines instead of a few large ones on the N1?

The N1 was a big disappointment after exploding on every single launch attempt. From what I have read, it seems like most of the attempts went wrong because one of the 30 engines exploded causing a ...
The Rocket fan's user avatar
1 vote
1 answer
233 views

How to find the average ambient pressure during rocket ascent?

I am trying to find the average ambient pressure that my rocket will flight through during its ascent to then determine the most optimum conditions in my combustion chamber and nozzle. I have ...
stanisverylow's user avatar
3 votes
1 answer
143 views

Equations evaluating engine performance

What kind of equation would best evaluate a rocket engine's performance in foreign atmospheres such as Mars? Does it matter that specific impulse does not consider air resistance? Should I focus on ...
boarbytes's user avatar
2 votes
0 answers
114 views

What engine cycle does the RS-88 and its hypergol derivative use?

A comment on this question Orange lines coming from rocket engine nozzle? stated in part The RS-88 is not a full flow engine and there is not a visible bypass exhaust. ... Perhaps they eject the ...
Organic Marble's user avatar
1 vote
0 answers
116 views

What are better ways to deliver heat directly to propellant in a Thermal Rocket design for use in launch than UV such as in the Nuclear Lightbulb?

Most advanced, high-power engine concepts that I came across aren’t suited for atmospheric launch, so I got curious about what kinds of engines could launch a very heavy craft from the surface of a ...
PedrohSpaceWolfy's user avatar
9 votes
1 answer
624 views

What is the area of the SSME nozzle knowing only thrust at sea level and in vacuum?

Looking at the SSME Wikipedia RS-25 Space Shuttle Engines, the data shown that the thrust at sea level ($F_{sl}$) is 1.816*10$^6$ N, while the thrust in vacuum ($F_{vac}$) is 2.278*10$^6$ N. Knowing ...
Julio Gonzalez-Saenz's user avatar
2 votes
1 answer
246 views

Discrepancies in thrust chamber dimensions for RL10

I've recently been developing some automated scripts in Python for the purpose of calculating engine parameters. I've been using the RocketCEA interface library, which links to NASA's Chemical ...
ecfedele's user avatar
  • 527
5 votes
0 answers
168 views

How Spacex's Raptor Rocket Engine starts?

How does the Spacex Raptor rocket engine start? What are the different stages of startup? Is the propellant pressure in the tanks sufficient to drive the turbopumps and ignite the preburners and then ...
Sebastyen Laroche's user avatar
2 votes
0 answers
186 views

Paraffin wax in solid motors

Paraffin wax is often used in (at least hypothetical) hybrid motors, mostly with N2O or HTP. Could it not, however, be used in a conventional configuration? Running at O/F of 12.4, 60 bar chamber ...
R. Hall's user avatar
  • 822
2 votes
1 answer
757 views

Question Deriving Mass Flow Rates for an Engine

I am trying to follow the calculations made in this blog post for a $50$ lbf. IPA/Nitrous Oxide engine, but cannot seem to get the values the author made for their propellant flow rates. Since the ...
Frank W's user avatar
  • 227
2 votes
1 answer
283 views

Estimations for Gas-Side Wall Temperature Within Rocket Engines

I'm in the process of reading Modern Engineering for Design of Liquid Propellant Rocket Engines and am stuck on this one example given in chapter 4 on the ...
Frank W's user avatar
  • 227
7 votes
1 answer
1k views

Is there an ultimate break-even point with rocket nozzle length or expansion ratio in a vacuum?

I know that in an atmosphere, you don't want your expansion ratio to be too high, or it will cause some big problems, and that vacuum engines are restricted by the space they have to fit in, but if we ...
zucculent's user avatar
  • 248
2 votes
1 answer
235 views

How to calculate catalyst bed geometry (length/radius) for a monopropellant thruster?

Catalyst design is central to the development of monopropellant thrusters and hence, ignoring its importance, as I have realised, is not very good practice. My question is if the mass flow rate, bed ...
R. Hall's user avatar
  • 822
4 votes
1 answer
631 views

Inconsistencies in calculating exhaust velocity

I'm quite sure this is either a small or just plain stupid mistake but my anxiety is getting the better of me. when calculating exhaust velocity this is the equation used: however I keep getting ...
R. Hall's user avatar
  • 822
5 votes
1 answer
218 views

Is there a significant reason why pintle injectors are only used in single configuration?

All of the resources I've managed to track down thus far about pintle injectors concern engines which only use a single, large central pintle for the entirety (or vast majority) of propellant supply ...
ecfedele's user avatar
  • 527

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