A bit of musing:

For those who have forgotten their school teachings... (or Europeans, etc. who do not understand inches, feet, and Horse-power) 2/12 is converting 2 inches (written 2") to feet (0.1667') - so Lb-inches (lb") become foot-pounds = engine torque, ('lbs) and when multiplied by rpm becomes the power... in lbs-ft/second (lbs'/s). Add a factor of 2 for "2 power strokes per revolution".

The 33000 is a conversion from lbs.ft/second to horsepower... Remember it now? - Or am I going senile? (

).

Please be careful of matching measurement units to the formula units.

Imperial Units are the most convenient "real world" units, but "Somewhere back in history" the French developed everything on a base 10 - which we call "Metric" (Meaning "measure" - nothing to do with base 10?). As this was based on the longest distance you can touch with a finger measured from your nose... - Perhaps as close as you may want to get to someone with Garlic breath? Unless you had been chewing Garlic as well? Who knows?

Koreans used Inches and feet, and somewhere along the line decided Korean Inches should be 1/10th of a foot.

I guess Ancient unit decision committees must have decided a foot was 12 inches long, although that is a size 17 or larger!

The Inch was based on the length of a man's thumb top joint. So very easy for anyone to have an approximate measure that fits in the hand! But finding a foot-long pediment is not so easy...

Then in rating engines you need to understand pressure. Power comes from mean pressure difference on the piston, not boiler pressure. Look at a typical

*indicator diagram* and you'll see how it is not easy to define the mean pressure of steam in the cylinder - for power calculations. It really depends also on the use of superheated steam, dry steam, or simple wet steam for the rating - which will be done against a Company or other standard, on a test bench dynamometer, and they'll have a best result for the sales blurb, but nothing you will be likely to repeat.

An indicator diagram for an engine with early cut-off (E), so in the "Efficient" mode, not "full power" mode.

A company may even fudge figures (innocently or not) by using "simple" calculations and a pressure figure that the engine will never see in reality.

Modern Regulations for cars try to make a level - common standard - but even so, VW and Daimler Benz were caught "cheating" Federal by using different software when on test to that used by Joe Bloggs in real life use! -And it cost them many Millions. But I doubt that the casting "makers" (sellers) are bound by similar regulation...

K2