Questions tagged [engines]
Questions regarding equipment used to propel a spacecraft or a rocket. Questions about attitude control jets should be tagged "attitude".
517
questions
1
vote
0
answers
94
views
What happens when the exhaust goes mach one
To create thrust and enough lift, you need a lot of mass thrown out at high velocities from a rocket engine. Most of the time this mass (exhaust) reaches over mach 1. I'm just curious whether this ...
- 1,097
4
votes
0
answers
88
views
How is the turbine in a rocket engine started?
I know that liquid rocket engines use a turbine to drive pumps that lead the Oxidizer and Fuel into the combustion chamber and that this turbine has a combustion chamber called the pre-burner. ...
- 1,097
6
votes
1
answer
583
views
How do closed cycle liquid engines actually work?
I've been researching Liquid Engines for quite a while now. I understand that there are two types of liquid engines, Closed cycle and Open cycle (Gas generator cycle). Open cycle engines simply let ...
- 1,097
1
vote
0
answers
167
views
Which rocket engines used this exotic cycle?
A "Hypergolic, Full Flow, and Closed Catalyst" cycle
Left side:
All hydrazine goes through the centrifugal fuel pump
All hydrazine goes through thermal decomposition
Out of it comes hot ...
- 131
19
votes
2
answers
2k
views
What purity of LOX is required for use in rocket engines?
Can any one suggest, is it necessary to check purity of LOX before it is used in an engine? What are the impurities which can affect its performance? What types of tests can we perform to check its ...
- 381
7
votes
1
answer
390
views
Why don't rocket engines use heat tiles on the inside?
I asked in chat about rocket engines not melting @ 3300°C despite steel melting at 1400°C. The two excellent answers were:
thermal mass was one answer
the propellants are often piped through tiny ...
- 621
4
votes
0
answers
231
views
Why did Starship lose an engine on IFT-4?
By T+0:00:06 at the latest, the Super Heavy carrying Starship for Integrated Flight Test 4 appears to have lost an engine (source and image). I know it's not a huge deal, as they can complete missions ...
- 5,287
4
votes
2
answers
2k
views
Has a rocket engine ever been reused by a second/third stage
While rockets are basically minimal fuel tanks*, engines are steel monsters that aught to both weight much and be expensive to manufacture**. Has there ever been tried discarding the depleted fuel ...
- 621
4
votes
1
answer
138
views
What is the dark brown gas emission seen during the ascent of Starship?
During the video (see below) of Starship IFT-4 there is a lot of brown smoke or gas in the Superheavy exhaust from near the start for almost 30 seconds. Is this NO2? If so roughly how much is produced?...
- 10.1k
3
votes
2
answers
989
views
What is the value of air anisotropy?
I am calculating a jet - gas nozzle and to calculate it, I need to know the anisotropy of the air, what is it equal to?
In this formula, the desired value is under the letter ...
17
votes
3
answers
5k
views
Is it true that engines built in Russia are still used to launch American spacecraft?
Is it true that today's launch of the American spacecraft Boeing Starliner still used Russian-made engines?
- 321
5
votes
2
answers
939
views
Are Hybrid Rocket Motors still in use?
There's always an outlook for liquid propellant and solid propellant rocket engines along with detonation engines and so on. But I hear very little about hybrid engines, have they simply been ...
- 1,097
1
vote
1
answer
207
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 ...
- 1,363
1
vote
0
answers
84
views
What is the ratio of air and ethyl alcohol that must be in order to power a rocket engine? [closed]
There is a rocket engine that will run on a fuel pair: air + ethyl alcohol, but what percentage of components should be supplied ...
4
votes
1
answer
204
views
Theoretical viability of a liquid rocket engine concept [closed]
[DISCLAIMER: I am an aerospace engineer undergrad and I do NOT want to build this. I wanted to come up with an alternative for the usual hypergolic mix so US military personnel would have one less ...
user54710
2
votes
1
answer
436
views
What rocket engine is this?
I came across a meme depicting a supposedly oxygen rich, fuel rich, and "engine rich" cycle of rocket engine. However, I'm pretty sure at least one of them is incorrect listing what looks a ...
- 1,739
2
votes
0
answers
56
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 ...
0
votes
1
answer
184
views
Does Raptor rocket engine of SpaceX include a cracker or fuel conversion system to crack the hydrocarbon fuel into its constituents?
In the Raptor rocket engine, where is the hot turbine exhaust gas transferred, when gaseous fuel arrives from the heat exchanger?
Does the Raptor rocket engine include a cracker or fuel conversion ...
- 11
10
votes
2
answers
2k
views
Hydrazine and liquid fluorine as a semi-cryogenic storable lunar space propellant
The use of liquid fluorine as an oxidizer diluted with liquid oxygen has been tested, but wasn't flown, by Bell and Rocketdyne, seperately.
http://www.astronautix.com/l/lf2hydrazine.html
It was ...
- 1,179
2
votes
0
answers
56
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!
- 21
4
votes
2
answers
292
views
Engine most likely to be available in the next 80 years to accelerate a craft at 1G for 4 weeks [closed]
I am wondering what type of engine would most likely be available in the next 80 that can constantly accelerate a spacecraft at 1G. Preferably, it could accelerate it for 4 weeks.
The engine could be ...
- 141
5
votes
0
answers
225
views
What are the arms for under the nozzle of NASA engine tests?
When NASA tests rocket engines at the Stennis Space Center, the engines have two arms under the nozzle. When the engines start these arms swing out of the way of the exhaust. What are these arms for?
...
- 51
2
votes
1
answer
317
views
Why aren't more companies manufacturing the RS-25 (Space Shuttle Main Engine)?
The RS-25 is a great engine with a terrific ISP. It was used 42 years ago (on April 12th 1981) for the first Space Shuttle flight; therefore, the most of the patents on it must have expired long ago. ...
- 1
4
votes
1
answer
186
views
How would one identify ionic thrust vs chemical thrust in an orbit transfer?
My nomenclature might be a bit off, I’m no expert but I’ve been reading to solve the question all the same. Say we detect an orbit transfer based off ephemeris records. We can get the 6 classic orbit ...
- 321
0
votes
0
answers
162
views
Can an orbital rocket have an airplane first stage? [duplicate]
The first stage of SpaceX's Nov 18 Starship launch was the Super Heavy. According to the Wikipedia page, it packs 3,400 tones of fuel. In the launch video, it shows the rocket reaches 27 km of ...
- 147
1
vote
0
answers
117
views
Single shaft turbopump vs two turbopumps
What are the pros and cons of using same turbopump for fuel and oxidizer and using 2 different pumps for both?
- 29
0
votes
0
answers
117
views
Dual expander bleed cycle
Would dual expander bleed cycle be a good idea?
The lox will pass through the nozzle and drive the lox pump
And the fuel will also pass through the nozzle to drive the fuel pump
Both will be expander ...
- 11
3
votes
0
answers
153
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 ...
1
vote
2
answers
389
views
Can hydrogen peroxide and propane be a good rocket propellant combination?
The decomposition of hydrogen peroxide can be used to spin the turbopump and then it can be mixed with propane in the combustion chamber
- 11
0
votes
0
answers
49
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 ...
0
votes
1
answer
105
views
Semi-Cryogenic HTP/LH2 engine?
Also see HTP as oxidizer for main propulsion
(for more info on history of H2O2/HTP in rocketry)
Note: HTP and H2O2 will be used interchangeably
I know the Black Arrow LV (The first orbital lipstick) ...
- 1,179
2
votes
1
answer
108
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 ...
- 1,179
15
votes
4
answers
5k
views
Do all artificial satellites have engines?
Novice question. A few days ago I watched a TV documentary about Virgin Orbit’s failed mission earlier this year to send satellites into orbit from Spaceport Cornwall. One of the satellites shown ...
- 253
2
votes
0
answers
114
views
Help with designing nozzle geometry for compressed air thruster
I am designing a compressed air thruster with a conical nozzle geometry. The general design consists of a compressed air tank, pneumatic tubing, and then the actual chamber with the nozzle. The ...
- 21
7
votes
2
answers
1k
views
Why do methane engines require burn-off igniters?
When I was watching the flight readiness test firing of the Vulcan’s BE-4 engines, I noticed that there were igniters similar to the ROFI igniters seen on liquid hydrogen rockets. Why do methane ...
- 319
1
vote
1
answer
2k
views
Why was Booster 9's 29 engine static fire ended 2.36 seconds early? [duplicate]
Suggested by Darth Pseudonym in answer to my other similar question. Recently (August 7), Booster 9 conducted a static fire test where it shutdown after only 2.74 of the planned 5 seconds of burn ...
- 5,287
1
vote
1
answer
244
views
The Boeing Big Onion - Why not use the atmospheric engines on landing?
https://www.aerospaceprojectsreview.com/blog/?p=1325
In relation the the Boeing "Big Onion" SSTO LV, I was doing some brief digging on it's flight profile.
(See the awesome Hazegrayart ...
- 1,179
-8
votes
1
answer
219
views
Mathematical inconsistences in rocket fuel [duplicate]
Saturn v is 2882 tons. Fuel is 30gj a tons.
Escape velocity (11 km/s). 350 TJ of KE.
The fuel is 85 TJ.
The Saturn v has 3 times less fuel than it would need to escape gravity.
- 1
12
votes
3
answers
3k
views
Would electrically powered thrusters on JWST have made it last for decades longer?
Since the lifespan of the James Webb Space Telescope is determined by the amount of fuel it can carry for its thrusters, used to decelerate the reaction wheels used to orient the telescope, and since ...
12
votes
2
answers
1k
views
Rocket Engine Failure Rate
I am a reciprocating engine machinist and understand that rocket engines are much much more complex. But I am curious why they have such a high failure rate. Even modern rockets are designed to ...
- 150
3
votes
0
answers
122
views
How do ablatively cooled rocket engines compare to regeneratively cooled ones, in terms of mass?
Assuming equivalent thrust and single continuous burn duration, is there a figure that roughly tells the difference in mass between these two engines cooling methods? This question focuses on first ...
user19132
4
votes
2
answers
317
views
How do Centrifugal Turbopumps work? How do you make one?
I recently visited Wikipedia to look at centrifugal pumps and axial pumps. Centrifugal pumps are very interesting, and I was wondering how they work in more depth. I really don't understand how they ...
- 41
3
votes
1
answer
135
views
ROFI Temperature
Since hydrogen-fueled rockets usually require Radial Outward Firing Igniters (ROFI), what is the temperature of the sparks from this system? When seen at RS-25/RS-68 ignition, they don't melt but ...
- 319
10
votes
1
answer
778
views
How common have the various orbital launchers' rocket engines been?
A fleeting thought on my sentiments about the disposability of RS-25s (rare! Only 47 made before the RS-25E/F contracts? Few remain! Complain about them being expended for SLS!) versus Raptors (one ...
- 13.6k
2
votes
0
answers
108
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 ...
2
votes
1
answer
195
views
Can rocket engines produce high voltages?
I was reading Michael Collins' account of the Apollo 11 TLI burn [1], and I wonder wheter the "flashes", "lightning", "sparks flying" and "insistent fireflies" ...
- 191
2
votes
2
answers
350
views
Do full flow rocket engines still use injectors? If so, how? How exactly are the oxidizer and fuel sent into the combustion chamber?
I'm learning about rocket engines and full flow engines, and I'm a little confused about what goes on in the combustion chamber. It was my understanding that injectors were pretty much necessary to ...
- 21
-1
votes
1
answer
91
views
Air-Augmentation on a VTO&L super heavy lift
I'm working on a basic design for an Air-Augmented first stage, which boosts the second, expendable, stage from a near-orbit, to allow for deorbit of the second stage.
Essentially it's an SSTO that ...
- 1,179
7
votes
1
answer
1k
views
Has the ISP been published for NASAs new rotating detonation engine demonstrator?
Nasa just announced successful testing of their new rotating detonation engine:
https://www.nasa.gov/centers/marshall/feature/nasa-validates-revolutionary-propulsion-design-for-deep-space-missions
I ...
- 1,001
0
votes
1
answer
148
views
What would be the most fuel-efficient propulsion solution to accelerate a 100-ton piece of NEO asteroid towards Earth?
We need acceleration to about 300-500 m/s relative to an NEO asteroid - to get to an LEO.
What is needed is the lightest package possible, that includes engine, fuel tanks, control module and ...
