The very first airplanes were constructed using only simple machine technology, as electronic devices were not yet available. USU notes six basic types of simple machines: inclined plane, wedge, screw, lever, pulley, and the wheel and axle. Rice University adds that gears, cams, cranks, springs, screws and belts are also simple machines. Each of these simple machines would have been used by various inventors and designers in old-fashioned airplanes.
Dr. John H. Lienhard, Ph.D., of the University of Houston explains that in the Wright Brothers' first airplane, they used a system of pulleys to control the rudders and "warp" the wings. In the U.S. Patent filed by the Wright Brothers on March 23, 1903, the description and drawings show a number of pulleys in use for the flying machine that would receive the patent three years later. Ropes would pass through pulleys and be connected to the ends of the fabric stretched over the wings with wire passing through a hemmed edge. The operator could manipulate the ropes attached to the fabric, a procedure they referred to as "warp the wings," for greater control over lift. The Wright Brothers' patent also mentions the use of springs. One use of springs is to control movement in the front edge of the horizontal rudder.
After describing the efforts of the Wright Brothers, Lienhard includes a photo on the UH website of Santos Dumont experimenting with his propeller-driven airplane. The photo shows the front of the plane with two wheels and an axle and a single wheel attached toward the rear of the plane. Wheels used in this way made it easier to transport the plane on the ground and also assisted with smoother landing. The Wright House website, devoted to the history of famous personages with that surname, provides a summary of the history of the Wright Brothers in which it is noted that the brothers realized a propeller was nothing more than a wing that rotates on its axis. In its most basic terms a propeller is simply a single wheel operating on one axle with the goal of creating a force of air. The propeller required an engine, and a four-cylinder model was custom-built to meet the brothers' specs. The engine featured a camshaft and other simple machines in its construction.
