Wright Brothers National Memorial, North Carolina

by Omega G. East

The second glider was stored in the wooden shed while the tent served as living quarters at Kill Devil Hills in 1901. Here Wilbur and Orville spent many hours discussing their experiments.

On the 1901 trip to camp the brothers brought with them parts to be assembled into a larger glider than the one tested in 1900. Knowing it would be impractical to house the larger glider with them in the tent, as they had done with the smaller one, they built a rough frame shed for the new glider and for use as a workshop. This building was 25 feet long and 16 feet wide. Its ends were hinged at the top near the gable parts to form doors so the glider could be removed or stored easily. The doors also served as awnings at the ends of the building.

When assembled, the new glider had a wingspan of 22 feet. It weighed 98 pounds, nearly double the weight of the earlier glider. To give it greater lifting power, the glider had a total lifting area of 290 square feet, considerably larger than the 165-foot wing area of the previous glider. The 1901 glider was a much larger machine than anyone had ever dared try to fly. It had the same system of control and general design as the first one. The Wrights increased the camber in this glider, from 1 in 22 to 1 in 12 to conform to the shape prescribed by Lilienthal’s tables of air pressure. Chanute and others had used these tables, and the brothers were rudely surprised upon finding that wings with a camber of 1 in 12 were even less efficient than the 1-in-22 camber wings they had used in 1900.

The Wrights were also dismayed to discover that the fore-and-aft control was not as effective in a machine with wings of 1-in-12 camber. At times when gliding, they were required to use all their skill and the full power of the rudder to prevent the glider from rearing up so sharply as to lose all headway and then to plunge toward the ground (a dangerous condition which they later referred to as “stalling”—an aeronautical term still in use). The brothers reduced the camber of the wings by adding little “trussing posts” to wires to depress the ribs and flatten the curvature from that used by others to 1 in 18 to make the wings more like those of their 1900 glider. This change resulted in control as good as it had been the year before.

Several hundred glides were made by Wilbur and Orville during the 1901 season of experiments. Using the slopes of Kill Devil Hill and West Hill, they sailed along in winds up to 27 miles an hour, breaking all records for distance in gliding. But the brothers were far from satisfied. They had learned a great deal about control, though their glider was still too feeble in lifting itself off the ground and staying aloft.

Occasionally in free flight, the warping of the wings to increase the angle of attack to recover lateral balance did not produce the desired result. The wing having the greater angle sometimes lost speed as it lifted, compared with the opposite wing having a lesser angle. The brothers then realized that the greater angle of the wing on one side gave more resistance to forward motion and reduced the relative speed of that wing. This decrease in speed more than counterbalanced the effect of the larger angle of the wing in producing lift. The Wrights determined that they must add something to their method of controlling equilibrium to insure that equal speeds at the wingtips would be maintained. However, a vertical tail as a solution to the problem was left for the next glider.

Contrary to the scientific texts they had read, it was becoming evident to the Wrights that the travel of the center of pressure on curved or cambered surfaces was not always in the forward direction as on a plane surface. They observed that when the angle of attack on a plane surface was decreased, the center of pressure did move toward the front edge; but on a cambered surface this was true only when large angles were being decreased.

Wilbur and Orville were discouraged that the ideas about pressures on curved surfaces and travel of center of pressure, concepts advanced by the most reputable writers on the subject, including Langley, were unreliable. So perplexing did the problem seem that the Wrights considered dropping their experiments altogether. It was apparent, then, that better scientific data were needed before the problems of flight could be solved.

On their way to Dayton from camp, Wilbur declared his belief to Orville that not within a thousand years would man ever fly! He later reduced this prophecy to 50 years. When they made known their discouragement to Chanute he urged the brothers to continue their researches, arguing that if they stopped experimenting it might be a long time before anyone else would come as near to understanding the problem or know how to work toward its solution. The admonitions of Chanute and their own intense interest in scientific inquiry led them to continue their research.