"John Husvar" wrote in message
...
In article ,
"Steve W." wrote:



HP is not directly measured in either case. It is based on an equation
using the torque and RPM. In a normal auto engine the torque and HP both
have a peak number. That is the number most often quoted. If the cooling
system is properly designed for the engine it will not overheat BUT it
will run warmer than it normally would. However most AUTO engines built
cannot handle running at the max numbers for long because they are made
so light to save fuel.


The rule of thumb we used for sizing brakes for overhead crane motors
was:

5250 X RPM / HP = torque

Should be able to get the HP as the unknown with a little algebra.



Hi John

The equation in your post has been published with a significant error. I
am sure it is a "typo". HP equals Torque times RPM.
Yeah, the automotive design guys *do* measure the HP of the engines they
develop.

It is kinda interesting that at about 5,250 RPM the Torque *and* the HP
are the same number when measured with the commonly used USA dimensions.
So, an engine producing 200 HP at 5,250 RPM will be producing 200 ft lbs
of Torque.

Jerry