Mass of the rocket engine's nozzle and combustion chamber as a percentage of the total engine

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Discussion Overview

The discussion revolves around the mass percentage of a rocket engine's combustion chamber and nozzle relative to the total engine mass. Participants explore this topic in the context of specific high-thrust engines, such as the Space Shuttle Main Engine (SSME) and Raptor engines, while considering design variations and proprietary information.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the approximate mass percentage of the combustion chamber and nozzle in relation to the total engine mass.
  • Another participant suggests that the answer may depend on the overall size of the engine and asks for clarification on which engine is of interest.
  • Some participants note that there is no definitive answer, as it varies by design, and question whether the inquiry includes turbomachinery or is limited to just the combustion chamber and nozzle.
  • One participant mentions that proprietary information limits the availability of specific data for the Raptor engine, while suggesting that the nozzle constitutes a significant fraction of the total mass for vacuum-optimized engines.
  • Technical details about the Space Shuttle Main Engine are provided, including specifications that could inform the discussion about mass distribution.
  • Another participant points out that the provided numbers do not allow for a direct calculation of the nozzle's mass, emphasizing the complexity of the nozzle's structure.

Areas of Agreement / Disagreement

Participants generally agree that the mass percentage varies by engine design and that specific data may be limited or proprietary. However, there is no consensus on exact figures or the implications of the provided specifications.

Contextual Notes

Limitations include the dependence on specific engine designs, the proprietary nature of some engine data, and the unresolved nature of how to accurately calculate the mass of the nozzle based on available information.

Timothy S.
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What is rocket engine combustion chamber plus nozzle's mass approximate percentage of the total engine's mass?

Thanks
 
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Have you been able to find anything with Google searching? It will likely depend on the overall size of the engine as well. What size engine are you most interested in?
 
Unfortunately, there’s no hard and fast answer to your question, as it’s going to vary from design to design.

Are we just looking at the thrust chamber assembly, or are we including the turbomachinery as well?
 
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Flyboy said:
Unfortunately, there’s no hard and fast answer to your question, as it’s going to vary from design to design.

Are we just looking at the thrust chamber assembly, or are we including the turbomachinery as well?
Just combustion chamber and nozzle, no preburners, turbopumps and other stuff
 
You won't find good numbers for Raptor as it's proprietary. For the Shuttle engine maybe, but I haven't found anything. The nozzle is a substantial fraction of the total engine mass, especially for vacuum-optimized engines.
 
From: http://www.braeunig.us/space/specs/shuttle.htm

SPACE SHUTTLE MAIN ENGINE
First flown: 12-Apr-1981
Number flown: 30 to end-1995
Dry mass: 3,177 kg
Length: 4.24 m
Maximum diameter: 2.39 m
Mounting: gimbaled by hydraulic actuators ±10.5o pitch/yaw
Engine cycle: staged combustion
Oxidizer: liquid oxygen, delivered at 408 kg/s
Fuel: liquid hydrogen, delivered at 68.0 kg/s
Mixture ratio: 6.0
Oxidizer turbopump: 261 kg mass, 28,500 rpm, 17,900 kW, 292.5 atm discharge pressure
Fuel turbopump: 351 kg mass, 46,230 kW, 415 atm discharge pressure
Thrust: 1,668/2,091 kN SL/vac at 100%, throttleable 65-109% in 1% increments. Launchis made at 104%
Specific impulse: 452.9 s vac, 363 s SL
Time to full thrust: 4.2 s
Expansion ratio: 77.5:1
Combustion chamber pressure: 204 atm (100% thrust)
Combustion chamber temperature: 3,300oC (100% thrust)
Burn time: 520 s typical, 761 s max


from: https://space.stackexchange.com/questions/43359/what-is-the-thickness-of-a-rocket-nozzle

At the exit plane the Space Shuttle Main Engine (SSME) nozzle was about 2 inches thick. This was a regeneratively cooled nozzle built up of tubing with a manifold encircling the exit.
enter image description here

Source: SSME Orientation (annotation mine)
(in case the above link doesn't work, here is where it points:

http://large.stanford.edu/courses/2011/ph240/nguyen1/docs/SSME_PRESENTATION.pdf)

All above info, and much more, found with:
http://www.google.com/search?hl=en&q=space+shuttle+weight+of+nozzle

Cheers,
Tom
 
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I found these numbers, but they don't let you calculate a mass of the nozzle. It's not a 2 inch sheet, the thickness is caused by individual thicker parts at the end of the nozzle.
 

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