"Robert Swinney" wrote in message
...

What I'd like to see is a comparison of the HP output of a steam engine
running on a given amount of input (boiler) pressure compared to the HP
output of the same engine running on the same amount of input compressed
air
pressure.

Analyze this from the standpoint of engine performance only, neglecting
boiler HP or compressor HP.

Ideas please.

Bob Swinney


I have measured the output of my 2 cylinder model engine on both steam and
air at the same pressure using a generator as a load. Measurements at 100
PSI and load adjusted via excitation to give the same RPM. Results are
steam 5 to 10 % greater than with air. I attribute this to the oil
viscosity change with temperature since the same oil and oil feed rate was
used for both tests. Cylinders were noticeably chilled when running on air.
Steam was superheated to 500 to 600 degree F area.

Joe Hanulec