13 Horsepower

12 Horsepower

After it's successful flight at Kitty Hawk, upon its return to Dayton
the Wright 'Flyer' underwent an extensive overhaul. The engine was
fitted with spark plugs and a magneto, replacing the original make &
break system. Whilst installing the magneto Orville discovered the
original timing was so retarded that the engine's output was reduced
by about half or about twelve horsepower. Timed correctly, the engine
provided more than enough power to carry a passenger.

This evening I was thumbing through a flyer of a different sort, this
one from Harbor Freight, in which they offered a 13 hp engine for
$370. The engine has a displacement of about 25 cubic inches and
claims an output of 17 ft/lbs @ 2500 rpm. The Harbor Freight engine
weighs78 lbs; the 'Flyer' engine ran about 200 lb.

With forty feet of span and more than 500 square feet of area, I've no
doubt that the Harbor Freight engine ...or even a pair of
them ...could power a replica of the Wright 'Flyer,' although I can't
imagine why anyone would want to do so. But the idea of using a
Harbor Freight engine meshes neatly with a recent thread about a
minimum flying machine.

The Wright's drove their eight-foot propellers at about 1200 rpm
through the use of a chain drive. Crossing the chain on one of the
props gave them contra-rotation.

Should a builder wish to produce a kind of power pod suitable for use
on a variety of low-cost, light-weight airframes, the thirteen
horsepower Harbor Freight engine, appears amenable to a 2:1 speed
reduction unit. Since this is the ratio between the cam and
crankshaft of all Otto Cycle engines, suitable belts and gearing is
available at your nearest automotive salvage yard.

-R.S.Hoover