"The Enlightenment" wrote in message ...
"ArtKramr" wrote in message
...
SNIP
..
The efficiency at the operating point for the axial unit of the Jumo
004B was 0.79. For the hybrid diagonal-axial He S11 it was 0.8. By
the time the He S11 entered production in 1945 the diagonal compressor
for the BMW 003C the HERMESO I was achieving 0.85 on the test stand
and the HERMESO II of the BMW 004D was expected to achieve 0.91. (By
this time the Germans were converting to more efficient reaction type
axial compressors over the impulse type axial seen on the Jumo 004B
and BMW 003A then in service) so they sacrificed a lot to achieve this
diagonal/compressor on the He S11.


There is a typing mistake in my above post. All the compressors of
the BMW003 series were axial NOT diagonal.

The BMW 003A (the 4 jet engines of which used on the Arado 234C and in
its BMW003E dorsal mount form as on the Heinker He162
Salamander/VolksJaeger) in fact had an axial type compressor. This
compressor was an axial "impulse" type in which the compression is
carried out by the turbine blades and the stator merely serves to
guide the airflow. The BMW 003A produced 800kg thrust.

To increase thrust without increasing fuel consumption ABB developed
for the BMW 003C an axial compressor known as the HERMESO I. The was
of the "reaction type" in which more precise machined blades provide
around 50% of the compression. The result is higher efficiency in the
case of HERMESO I this was 0.84 Thus the BMW 003C achieved the same
thrust as the Jumo 004B with the samller weight, fuel cosumption of
the already good BMW003.

The BMW 003D had the refined HERMES0 II with a bench tested efficiency
of 0.91. The engine was expected to have a thrust of 1100kg and to be
used on on range recon versions of the Arado 234. For combat the
tougher 1300kg thrust He S11 with its diagonal compressor was seen as
superior.