As a general proposition it takes much more power to
propel an airship a given number of miles in a certain
time than it does an automobile carrying a far heavier
load. Automobiles with a gross load of 4,000 pounds,
and equipped with engines of 30 horsepower, have travelled
considerable distances at the rate of 50 miles an
hour. This is an equivalent of about 134 pounds per
horsepower. For an average modern flying machine,
with a total load, machine and passengers, of 1,200
pounds, and equipped with a 50-horsepower engine, 50
miles an hour is the maximum. Here we have the equivalent
of exactly 24 pounds per horsepower. Why this
great difference?
No less an authority than Mr. Octave Chanute answers
the question in a plain, easily understood manner. He
says:
"In the case of an automobile the ground furnishes a
stable support; in the case of a flying machine the engine
must furnish the support and also velocity by which the
apparatus is sustained in the air."
