Jacques Bréguet—Gyroplane-Laboratoire

Unlike the airplane, the helicopter had a long and trouble-plagued development. Whereas the Wright brothers get most of the credit for developing the airplane, many more people, on several continents, contributed to the development of the helicopter.

The biggest problem with the various early helicopter designs produced by Louis and Jacques Bréguet, Igor Sikorsky, Juan de la Cierva, and others was that although they could lift off the ground, they could not be controlled in flight. Inventors did not understand the aeronautical forces facing the helicopter and did not know how to design mechanical devices to address these forces.

To control a helicopter, inventors had to devise a means of directing the downward thrust of the rotors slightly off-center so the craft would move in the opposite direction. They also had to find a way to overcome the twisting motion, or torque, induced by the heavy turning rotor blades.

By the early 1930s, Louis Bréguet, one of the pioneers of helicopter development, began to think about helicopters again, establishing the Syndicate for Gyroplane Studies and hiring a young engineer named Rene Dorand. Bréguet took a far more cautious approach than he had more than a decade before. He oversaw the building of a helicopter that attempted to solve the problems of stability and control. He cautiously named this aircraft the Gyroplane-Laboratoire, clearly identifying it as an experimental aircraft.

To make the most of a limited budget, Dorand built the craft as much as possible from available bits and pieces. He used a Bréguet 19 airplane fuselage for the craft's body and a surplus aircraft engine to power it. The craft consisted of a thin metallic frame with a tail and three wheels—one on either side mounted on outriggers and a smaller one at the front of the aircraft. The engine was located forward, and the pilot sat behind it in an open cage. Two twin-bladed rotors, each nearly 54 feet (16.5 meters) long, were stacked coaxially on top of each other, rotating in opposite directions and thereby canceling out their torque. The rotor blades were attached to the shaft with a hinge mechanism (they were "articulated"), and the pitch of the rotor could be increased or decreased on each revolution (cyclic pitch control), thereby controlling lift. If the propellers were angled so they pushed the air down more, lift would increase, and the craft would rise.

Bréguet had confidence in his machine despite warnings from his mechanics that the controls were not yet perfected. In November 1933, he scheduled a demonstration flight for his investors. A former French Army pilot named Maurice Claisse reluctantly agreed to make the test. He climbed into the craft and started the engine as three men stood by on the ground to hold the machine. The rotors turned and the craft immediately tilted to the right. As bystanders—including the ground-handlers—ran for cover, the rotor blades hit the ground and shattered. Fortunately, no one was hurt, but the aircraft was badly damaged, postponing any further tests.

Throughout 1934 and 1935, Bréguet extensively modified his craft and performed ground tests. His most important addition was a new system for controlling the direction of flight. By tilting the axle on which the rotors turned, pitching the rotor disk, the helicopter could be made to move forward, sideways, or even backward. He added a system for controlling the yaw of the helicopter (turning the helicopter to the left or right) by allowing the two rotors to each have a different pitch (differential collective pitch).

On June 26, 1935, test pilot Maurice Claisse hopped in the craft again. This time he was able to lift it off the ground without crashing. He then made several flights at speeds of 18 to 30 miles per hour (29 to 48 kilometers per hour). The French Air Ministry was so impressed it gave Bréguet a contract that covered the cost of flight trials and provided a million-franc-bonus if all performance goals were achieved.

By December 1935, Bréguet began the series of test flights. He then proceeded to push his aircraft far beyond the limits of any previous rotary aircraft. He was not always successful. Occasionally the rotors collided with each other (a problem that still exists today on helicopters with a similar design) upon landing or the rivets popped out. But Bréguet repaired the craft in time for each new test flight. The craft achieved a record speed of 75 miles per hour (121 kilometers per hour) and climbed to a record altitude of 518 feet (158 meters), remaining in the air for more than an hour. It stayed in a hover over one spot for ten minutes—also a record. Bréguet completed his initial tests in late 1936 and received the one-million-franc bonus.

Bréguet received another Air Ministry contract for further development but made little progress over the next several years. One big concern about helicopters was what would happen if the engine failed in flight. An airplane could glide to the ground, but a helicopter needed to descend while "autorotating," essentially using the rotor as a parachute. Bréguet's aircraft was badly damaged during an autorotation test in 1939. With war imminent, Bréguet put his craft in storage and turned his attention to the full-scale production of bombers. His helicopter was ultimately destroyed in 1943 during the Allied bombing of the Villacoublay Airfield.

The stacked rotors that Bréguet used for his Gyroplane was not a popular design in the West. However, it was used by the Soviet designer Kamov for a number of anti-submarine helicopters such as the Ka-25 Hormone and the Ka-27 Helix, as well as the attack helicopter known as the Ka-50 Werewolf.

Although Bréguet's aircraft was capable of lifting off the ground, it was too heavy for long flights. It also had limited maneuverability. Many aviation experts consider Bréguet's aircraft to be the first completely successful helicopter. But it was soon upstaged by a more impressive German craft, the Fa 61.

—Dwayne A. Day

Sources:

Carey, Keith. The Helicopter. Blue Ridge Summit, Penn.: Tab Books, 1986.

Spenser, Jay P. Whirlybirds:  A History of U.S. Helicopter Pioneers. Seattle, Wash.: University of Washington Press, 1998.

Young, Warren R. The Helicopters. Alexandria, Va.: Time-Life Books, 1982.

Further Reading:

Gablehouse, Charles. Helicopters and Autogiros; A History of Rotating-wing and V/STOL Aviation. Philadelphia: J.B. Lippincott Company, 1969.

Liberatore, E.K. Helicopters Before Helicopters. Malabar, Fla.: Krieger Publishing Company, 1998.

Young, Warren R. The Helicopters. Alexandria, Va.: Time-Life Books, 1982.

Brain, Marshall. "How Helicopters Work." http://www.howstuffworks.com/helicopter.htm.