by Orville Wright
The flights of the 1902 glider had
demonstrated the efficiency of our system for maintaining
equilibrium, and also the accuracy of the laboratory work
upon which the design of the glider was based. We then
felt that we were prepared to calculate in advan ce the
performance of machines with a degree of accuracy that
had never been possible with the data and tables
possessed by our predecessors. Before leaving camp in
1902 we were already at work on the general design of a
new machine which we proposed to propel with a motor.
1902 glider and camp
Immediately upon our return to Dayton, we wrote to a
number of automobile and motor builders, stating the
purpose for which we desired a motor, and asking whether
they could furnish one that would develop eight-brake
horse power, with a weight complete not exceeding 200
pounds. Most of the companies answered that they were too
busy with their regular business to undertake the
building of such a motor for us; but one company replied
that they had motors rated at 8 h.p. according to the
French system of ratings, which weighed only 135 pounds,
and that if we thought this motor would develop enough
power for our purpose, they would be glad to sell us one.
After an examination of the particulars of this motor,
from which we
learned that it had but a single cylinder of 4 inch bore
and 5 inch stroke, we were afraid that it was much
overrated. Unless the motor would develop a full 8 brake
horse power, it would be useless for our purpose.
Finally we decided to undertake the building of the motor
ourselves. We estimated that we could make one of four
cylinders with 4 inch bore and 4 inch stroke, weighing
not over two hundred pounds, including all accessories.
Our only experience up to that time in the building of
gasoline motors had been in the construction of an
air-cooled motor, 5 inch bore
and 7 inch stroke, which was used to run the machinery of
our small workshop. To be certain that four cylinders of
the size we had adopted (4" x 4") would develop
the necessary 8 horse power, we first fitted them into a
temporary frame of simple and cheap construction. In just
six weeks from the time the design was started, we had
the motor on the block testing its power. The ability to
do this so quickly was largely due to the enthusiastic
and efficient services of Mr. C.E. Taylor, who did all
the machine work in our shop for the first as well as the
succeeding experimental machines. There was no provision
for lubricating either cylinders or bearings while this
motor was running. For that reason it was not possible to
run it more than a minute or two at a time. In these
short tests the motor developed about nine horse power.
We were then satisfied that, with proper lubrication and
better adjustments, a little more power could be
expected. The completion of the motor according to
drawing was, therefore, proceeded with at once.