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FAA Aviation News, July - August 1991

Development of the helicopter can be likened to a jigsaw puzzle with the correct placement of each piece solving such problems as lack of power, stability, control, and torque. From its earliest mention as a fourth century Chinese toy, the idea of vertical flight has intrigued succeeding generations with each contributing another piece to the puzzle, but progress was slow. In fact, it was not until the 1860's that vertical flight aircraft were even given a name. Viscount Gustave de Ponton d'Amecourt combined the words "heliko" (meaning spiral) and "pteron" (meaning wing) coining the word "helicopteres." It was only in the beginning of the 20th century that technology could even begin to make practical experimentation of full-size models possible.

After the Wright brothers proved that powered, manned flight was possible, the Deutsch-Archdeacon prize was offered to encourage the further growth of aviation. Named after its wealthy sponsors, the prize was offered to the first pilot to fly around a specified one kilometer (0.62 mile) course.

The race was on with the contestants experimenting with a variety of designs from fixed-wing aircraft to primitive helicopters. Of all the aircraft builders, only the Wrights had more than met the prize requirements with flights of more than 24 miles lasting over 30 minutes. However, for some reason they chose not to compete, leaving the field wide open to all the others, who had barely flown a quarter of the required distance. It is not surprising that nearly every hopeful aircraft inventor was scrambling for the 50,000 franc ($10,000) prize. One of these contestants was a French engineer, Paul Cornu from Lisieux, a firm believer in vertical flight.

In 1906 Cornu had flown successfully a model helicopter that weighed 28 pounds. Feeling he had a good chance to win the Deutsch-Archdeacon prize, he built a full-scale model that had been financed by 125 friends. They must have believed his sales pitch because each chipped in the then astronomical sum of 100 francs ($20). By August of 1907 he was ready to test fly the full-scale machine, but not confident enough yet to fly it himself. The "pilot" would be a 110-pound bag of sand. After a series of adjustments based on the results of the test flights, he was ready to act as test pilot.

Cornu's helicopter was a compact two-rotor machine measuring 40 feet 4 inches in length and weighing a total of 573 pounds. The framework consisted of 20-foot steel tubing bent to form a long wide U with the rotors mounted in tandem on either end. The paddle-shaped rotor blades were 5 feet 11 inches in length and linked by a leather drive belt running over pulleys above the pilot's head. It had two tilted wind vanes mounted under the main rotors that were supposed to propel the machine forward by deflecting the slipstream from the rotors backwards and downwards. However, it never functioned successfully as the driving force of the wind vanes was weak. The cockpit area was compact to say the least. The 24 horsepower Antoinette engine was practically in the pilot's lap and the pilot's seat was directly over the battery and the landing gear, which was composed of four bicycle tires.

On November 13,1907, Cornu took off in this ungainly looking ancestor of the helicopter and ascended to the staggering altitude of one foot and hovered there for about 20 seconds. This earned him a place in aviation history for making the first successful manned free flight in a helicopter. On later flights, he managed a height of five feet and was timed at six miles per hour in forward flight. He also gained, by accident, a record for two-person flight when his brother grabbed the craft's frame to keep it from tipping and ended up in the air instead. The brother apparently was not terribly impressed with his record-making flight, because the helicopter was tethered for all future test flights.

Over the next few months Cornu would lift off about 15 times and achieve forward and backward movement in more than 300 flight attempts. Then the unthinkable happened on January 13. Henry Farman's fixed-wing aircraft flew around the one kilometer course and won the Deutsch-Archdeacon prize.

Paul Cornu gave up his helicopter experiments in 1909. He could not seem to conquer problems involving the aircraft's severe lack of control and stability in flight. More importantly, he lacked the money to continue his experiments, so he faded from vertical flight history. Although his helicopter was not as successful as he had anticipated, Cornu had added one more piece to the vertical flight puzzle -- the first true "free flight" of a manned helicopter.

The emergence of the total picture would have to wait 30 years for Igor Sikorsky to successfully develop the first practical helicopter. By the mid-1940's another tandem helicopter was developed -- this time successful -- by Frank Piasecki. No doubt its nickname, the "Flying Banana," would have brought a smile of irony and pride to a certain French engineer.

Contributed by P. Felton.

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