The Airplane - Jay Spenser [77]
Hubert Latham directed the Antoinette in flight using fore-and-aft control wheels at each side of the cockpit.
National Air and Space Museum, Smithsonian Institution
As for control systems using wheels, the Deperdussin company came up with the winner. Drawing on maritime practice, Deperdussin pilots simply turned a control wheel in the direction they wished to bank. To this intuitive lateral control, Deperdussin added fore-and-aft wheel movement providing equally intuitive pitch control via the elevator.
The Deperdussin, Antoinette, Blériot XI, Farman, and almost all other early airplanes used a pivoting foot bar to control the yaw axis. The “rudder bar” idea caught on quickly because it was so easy to wire up and intuitive to use. To yaw the airplane’s nose, one had only to push with the foot on the side to which you wished the nose to go. The rudder bar also facilitated smooth turns, which require coordinated application of yaw and roll control.
After World War I, rudder bars gradually gave way to today’s rudder pedals. Although they function identically, pedals have the advantages of greater comfort during maneuvers, since one’s feet are less likely to slip. Rudder pedals also accommodate wheel brakes, actuated by depressing the tips of the pedals with one’s toes.
Interestingly, the Wrights gave up foot controls after their 1901 Glider. In their 1905 and 1908 Flyers, all three axes were controlled independently by the hands, which also managed engine throttling. Glenn Curtiss likewise went his own way. The June Bug and Model D Pushers had a wheel on a movable control column. As with most airplanes, pulling the wheel toward you brought the nose up, while pushing it away put the airplane into a dive. However, turning the wheel laterally worked the rudder to yaw the airplane’s nose left or right. Roll was controlled by a shoulder-operated yoke that worked the ailerons. To bank, one simply tilted one’s body to the desired side.
All this was potentially very confusing. It lasted until World War I, which drove consensus because large numbers of pilots needed to be trained. Once sent off to the front, moreover, they had to be able to fly whatever airplanes they found there and to transition to newer equipment as it arrived.
Cockpit instruments likewise evolved haphazardly. These fall into two basic classes: flight instruments and engine instruments. The former came first and had the humblest of births at the hands of the Wrights at Huffman Prairie. As aviation historian and Wright biographer Tom Crouch recounts:
The brothers had trouble orienting themselves in turns, frequently miscalculating, banking too steeply, or allowing the nose to rise so high that the aircraft stalled. The answer was a long string tied to the crossbar of the elevator. When the craft was flying straight and level, the string blew directly back toward the pilot. When banking, or flying with the nose up or down, the position of the string enabled him to gauge the attitude of his machine.1
The first real instrument was probably the compass. Once pilots began flying any distance, they needed to know where they were headed. Otherwise, fliers before World War I flew only by external cues and the feel of the airplane. That changed in the war, of course, because military pilots needed to know how high they were, how fast they were flying, how much fuel they had left, and how healthy their engines were.
Although World War I stuffed more instruments in the cockpit, it did not drive consensus. Instead, it was pretty much up to each designer to place these instruments at his whim. A generation later, World War II finally standardized the layout of cockpit instruments.
In between these wars, a quiet revolution occurred in aviation: human