Employment was up nearly everywhere. In the state of New York practically the entire labor force was working. Wages were rising, the national wealth increasing. Instead of a national debt, there was a surplus of $45 million. In Washington one sensed “a new velocity” under the leadership of Theodore Roosevelt. The country was about to take on the building of the Panama Canal, picking up where the French had failed. No new year had “ever brought the people of the United States a more encouraging outlook,” said the Albuquerque Journal-Democrat. Further, as noted in numerous editorials, Sunday sermons, and at many a family dinner table, the world was at peace.
One of the few puzzling questions to be considered, said the Philadelphia Inquirer, was why, so far, after so much attention had been paid to “aerial navigation,” had there been so few results?
It was shortly before the New Year when the Wright brothers sent out letters to manufacturers of automobile engines in seven states asking if they could supply an off-the-shelf engine light enough in weight but with sufficient power for their purposes. There was only one response, and in that case the motor was much too heavy. So again they had some original work to do and they had had no experience building engines.
In time to come the brothers would be widely portrayed as a couple of clever, hometown bicycle mechanics who managed to succeed where so many others had failed because of their good old-fashioned American knack for solving seemingly impossible mechanical problems. This was true only in part.
For Charlie Taylor, however, the description applied almost perfectly, except that he was more than a clever mechanic, he was a brilliant mechanic and for the brothers a godsend. If sister Katharine found Charlie’s claim to know all the answers unbearable, Wilbur and Orville never lost sight of his ability and enormous value to their efforts. And he himself well understood how far beyond him they were in so many ways. As he later said, boasting about them, “Those two sure knew their physics. I guess that’s why they always knew what they were doing and hardly ever guessed at anything.” As for building the engine:
While the boys were handy with tools, they had never done much machine-work and anyway they were busy on the air frame. It was up to me. . . . We didn’t make any drawings. One of us would sketch out the part we were talking about on a piece of scratch paper and I’d spike the sketch over my bench.
His only prior experience with a gasoline engine had been trying to repair one in an automobile a few years before. But that January, working in the back shop with the same metal lathe and drill press used for building bicycles, he went to work and six weeks later had it finished.
The motor had four cylinders with a 4-inch bore and a 4-inch stroke. It was intended to deliver 8 horsepower and weigh no more than 200 pounds, to carry a total of 675 pounds, the estimated combined weight of the flying machine and an operator. As it turned out, the motor Charlie built weighed only 152 pounds, for the reason that the engine block was of cast aluminum provided by the up-and-coming Aluminum Company of America based in Pittsburgh. Other materials came from Dayton manufacturers and suppliers, but the work of boring out the aluminum for the independent cylinders and making the cast iron piston rings was all done by one man with a drooping walrus mustache working in the back room at the bicycle shop.
The fuel system was simple [he would later explain]. A one gallon fuel tank was [to be] suspended from a wing strut, and the gasoline fed by gravity down a tube to the engine. . . . There was no carburetor. . . . The fuel was fed into a shallow chamber in the manifold. Raw gas blended with air in this chamber, which was next to the cylinders and heated up rather quickly, thus helping to vaporize the mixture. The engine was started by priming each cylinder with a few drops of raw gas.
Compared to later engines all was amazingly simple and crude. The ignition was of the “make-and-break type” in Charlie’s expression, probably meaning that if broken it could be quickly fixed. There were no spark plugs.
The spark was made by the opening and closing of two contact points inside the combustion chamber. These were operated by shafts and cams geared to the main camshaft. The ignition switch was an ordinary single-throw knife switch we bought at a hardware store.
The “little gas motor,” as Bishop Wright called it, was finished by mid-February, and when started up in the shop the first time the racket and clouds of smoke were nearly unbearable. When further tested the next day, the engine block cracked. Dripping gasoline had frozen the bearings, breaking the engine body and frame.
Another two months went by before a second block would be delivered from Pittsburgh. This engine worked fine and as a bonus delivered an unexpected 12 horsepower.
Meantime, the design of the propellers had become a still bigger challenge. “I think the hardest job Will and Orv had was with the propellers,” Charlie later said. “I don’t believe they ever were given enough credit for that development.”
The problem became more complex the more the brothers studied it. Much to their surprise, they could find no existing data on air propellers. They had assumed they could go by whatever rule-of-thumb marine engineers used for the propellers on boats, and accordingly drew on the resources of the Dayton library only to find that after a hundred years in use the exact action of a screw propeller was still obscure. Once more they were left no choice but to solve the problem themselves. “Our minds,” said Orville, “became so obsessed with it that we could do little other work.”
They began to see the propeller as an airplane wing traveling in a spiral course, and that if they could calculate the effect of a wing traveling a straight course, why could they not calculate the effect of one traveling in a spiral course?
But on further consideration [Orville would explain], it is hard to find even a point from which to make a start; for nothing about a propeller, or the medium in which it acts, stands still for a moment. The thrust depends upon the speed and the angle at which the blade strikes the air; the angle at which the blade strikes the air depends on the speed at which the propeller is turning, the speed the machine is traveling forward, and the speed at which the air is slipping backward; the slip of the air backward depends on the thrust exerted by the propeller, and the amount of air acted upon. When any one of these change, it changes all the rest, as they are all interdependent on one another.
After several months of study and discussion they had come to understand that the thrust generated by a standing propeller was no indication of the thrust when in motion, and that the only realistic way to test the efficiency of a propeller would be to try it out on the flying machine.