View Single Post
  #6  
Old February 10th 06, 11:54 AM posted to rec.aviation.homebuilt
external usenet poster
 
Posts: n/a
Default Differences between automotive & airplane engines


"Alan Baker" wrote in message
...
In article .com,
wrote:

A by-product of that lack of education is how Americans view
'horsepower,' typically insisting that 50hp (at 5000rpm) is EXACTLY THE
SAME as 50hp (at 1000rpm). Indeed, most will whip out their calculator
and 'prove' they are identical :-) But as the Wright brothers
discovered more than a hundred years ago, horsepower is not a factor in
the equation of flight. With powered flight, the factor we must
concern ourselves with most is thrust. Working back through the
equation, for a given propeller efficiency & rpm we will eventually
arrive at a given quanta of torque which then may be converted into
units of 'horsepower,' should we wish to do so, although it serves no
useful purpose. But when we DO use 'horsepower' we must be careful to
never use it in isolation, always identifing the rotational speed at
which that 'horsepower' is being produced.


Absolutely and utterly wrong.

It is *torque* which must always be associated with the rotational speed
at which it is being produced.

--
Alan Baker


Alan,

You do understand that if you know the HP at a given rpm, you can easily
calculate torque.

KB