| September/October 1987

Hi! to my dear readers and friends I am very happy we have quite a lot of copy, good stories and information, so I'm hoping it will make you very happy and I am, for this time, not going to add anything, but to hope you are having a wonderful summer and I know there are still a lot of activities going on. Read and enjoy and be sure you read all the articles and stories and especially the last letter in the column.

And now for the article...

'I have been a subscriber to the ALBUM for over 30 years and this is my first letter. On pages 10 and 11 of the May/June issue, an article of Mr. Rixmann covers the subject of Drawbar Horsepower. As a mechanical engineer, I become incensed when others present a solution to a mathematical problem without any consideration as to the units used and how they arrived at the answer.'

Although 60 divided by 17 is 3.428, what are the units of 60 ? Answer: 88 feet x 60 sec/min x 60 min/hr x 1/5280 miles/feet =60 sec-miles/hr. 60 sec-miles/hr x 1/17.5 sec=3.428 miles/hr. Why the author solved for miles per hour is a puzzle. As stated in the article, one horsepower=33,000 lb/ft/min. Obviously the units of 12,958 are lb/miles/hr. But now the real puzzle? -375! The author calls this a 'constant factor'. Actually its units are lb-miles-HP/hr!

A simpler and more traditional solution as generally used by the profession, is 88 ft x 1/17.5 sec x 60 sec/min x 3780 lb x 1/33,000 min-HP/lb =34.56 HP. The foregoing is as important in knowing that your steam guage reads in pounds/square inch and not pounds/square foot!'

This letter came from WILLIAM H. RICHARDSON, JR., 540 Mill, Sheboygan Falls, Wisconsin 53085 and I'm sure the readers that are into this kind of fractions and statistics will understand.