On 4 Oct 1996, David Rupert wrote:
> Scions,
>
> Since we are discussing strange measurement systems, I have one that has
>bugged
> me for years. I recently saw it crop up again in my latest issue of Classic &
> Sportcar, with regard to the early Triumph Glorias and the Southern Cross.
>What
> the heck is hp? One of the cars in the article was described as, "A 10.5 hp
> model featuring a 48 bhp engine", or something to that effect. I'm assuming
> that it is NOT some arcane method of measuring horsepower. My first wild
>guess
> is that it has something to do with weight. Could someone from across the
>pond
> educate a confused American?
>
> Thanks,
>
> David Rupert
> 75701.242@compuserve.com
> 1967 TR4A (rigid axle)
> 1980 TR7 convertible
> Waterford, Michigan USA
>
"hp" stands for horsepower, a calculated value that was used to
determine the tax paid by the vehicle owner in order for him to operate
it on a public road. The claculation included engine capacity as a
variable, and most engines of less than 1 litre (approx) were 8 hp
engines, 1.2 litre (approx) were 10 hp, etc etc. It had nothing to do
with brake horsepower. Those of us who are Triumph fans are aware of
the Standard 8 - it had an 8 horsepower engine by this method of
classification. The tax categories went away in the 1950's, I believe.
Also, I think this was sometimes referred to as "RAC horsepower",
because the formula was developed by the Royal Automobile Club. This
last part is a little fuzzy, however.
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