I've been comparing period cars with Fords and one problem is no consistency between makes (horsepower rating). I found this conversion table in an August 1906 "Automobile" magazine. What do you guys think of it?
The second column to the right bottom of the "Bore" category is at 1000 rpm. Take the Bore, then add the appropriate Stroke column. Using a Model T 3 3/4 X 4 in. bore/stroke, go to the 3 3/4 box (left), then right to the 1" up/down column (adding one inch to the "base" 3 inch bore column if I'm doing this correctly). At the 1,000 rpm (second of the two boxes), the number is 5.97. 5.97 times 4 cylinders equals just under 24 hp.
Those sort of tables are useful I suppose for the purpose of taxation (see Great Britain) but they ignore the fact that engines can have the same displacement in cubic inches but be vastly different in horsepower from one another.
For example, a flathead of 300 cubic inches would not have as much power as a T head of the same displacement and compression ratio. A lot depends on camshaft design, carburetor flow rate, combustion chamber shape, valve diameters, exhaust system design and any number of other design factors.
What you say is clearly true, Royce. It makes me wonder if there's ever been an engine developed that is "optimum", meaning all the factors you mentioned as well as others have been used to build the "best" internal combustion engine possible in a given power range. Further, if it's possible to do that, why don't all manufacturers build essentially the same engine?
There are always new ideas. Nothing is or ever will be ideal or optimum. There's always some way to improve something that we have not discovered.
Rob - That is why Nebraska started tractor testing, manufacturers claims were all over the place, I'm sure the same could be said of automobile manufacturing but they were not being held to any standard.
A drift from T's, but almost on topic I think and sort of interesting:
As I've mentioned here before, I served on a diesel/electric submarine for about 3 years in the early '70's. It was the USS Trigger (SS 564), commissioned in 1951 and the first "New High Speed Attack Submarine" of her class. She was originally fitted with radial diesel engines made by GM's Cleveland Division. They were referred to as "pancake" engines due to their design. GM spent $10 million and 5 years developing them. They claimed the new engines took up 1/3 less space than comparable power units and produced twice the horsepower per pound of any submarine engine ever used.
Turned out they were a total flop. As I recall being told, it took only a few years of operations with these new engines before their unreliability was so well documented that they were removed and replaced with FM 8's.
It all happened before my time, but I always thought it was interesting that a major company and the US Navy bet on something new and untried that turned out to be such a failure.
Back in the 50's GM achieved the magic 1hp per cu in. Now days that's nothing.
It was all about maintaining torque at high rpm's back then. The high horsepower one's were almost always at 6000 rpm. They weren't to hot at low rpm's though. Also, they had to hold together at the high rpm's.