1958 RZ14 compared to SSME

Spark

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RZ14 compared to SSME
In 1958 the RZ14 LOX Kerosene rocket engine was designed/proposed as an alternative very advanced UK engine for the Blue Streak family of Military SLVs.
A single RZ14 could, would replace two RZ12 rocket engines and could be specified for the build when ordering a vehicle depending on the mission type envisaged.
The RZ14 envisaged would have had a thrust rating that would have been greater than the Shuttle’s first Rocketdyne SSME.
The RZ14 would have had a sea-level thrust estimated at 400,000lbf from an engine with a mass given as about 2,450lbs compared to the SSME’s 7,200lbs.
The SSME was an outstanding success but I am surprised at the magnitude of difference in the mass of an engine unit needed for a reusable unit when compared to the RZ14.
Was the SSME Combustion chamber and nozzle optimised for thrust conditions encountered in space?
What was the mass of the SSME combustion chamber and nozzle?
Were the first SSME combustion chamber and nozzle manufactured using Bristol/MBB copper deposition technology?
 
Spark said:
RZ14 compared to SSME
In 1958 the RZ14 LOX Kerosene rocket engine was designed/proposed as an alternative very advanced UK engine for the Blue Streak family of Military SLVs.
A single RZ14 could, would replace two RZ12 rocket engines and could be specified for the build when ordering a vehicle depending on the mission type envisaged.
The RZ14 envisaged would have had a thrust rating that would have been greater than the Shuttle’s first Rocketdyne SSME.
The RZ14 would have had a sea-level thrust estimated at 400,000lbf from an engine with a mass given as about 2,450lbs compared to the SSME’s 7,200lbs.
The SSME was an outstanding success but I am surprised at the magnitude of difference in the mass of an engine unit needed for a reusable unit when compared to the RZ14.
Was the SSME Combustion chamber and nozzle optimised for thrust conditions encountered in space?
What was the mass of the SSME combustion chamber and nozzle?
Were the first SSME combustion chamber and nozzle manufactured using Bristol/MBB copper deposition technology?

The staged combustion SSME used higher pressures than found in typical gas generator engines. That accounts for most of mass.

There are so many differences that it is not a valid comparisons. Thrust is not the only parameter that matters.
Also, was the RZ14 ever built? If not, then its projected weight is not valid for comparison.
 
There is a density issue: a hydrogen engine has to have larger diameter plumping than a kerosene engine would. Couple that with the pressure issue, and weight increase would be substantial.
 

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