Santos-Dumont 14-bis

The 14-bis (Quatorze-bis), also known as Oiseau de proie ("bird of prey" in French), was a pioneer era canard biplane designed and built by Brazilian engineer Alberto Santos-Dumont. On 23 October 1906, in Paris, France, it performed the first officially witnessed unaided takeoff and flight by a heavier-than-air aircraft.^[1]

Conception, development, and initial tests

In June 1905, Gabriel Voisin tested a glider by having it towed by a fast boat on the River Seine, making a flight of over 500 ft (150 m). The glider's wing configuration was made up of Hargrave cells, a box kite-type structure that provided a degree of inherent stability. This established the Hargrave cell as a configuration useful not only for kites but also for heavier-than-air aircraft. Santos-Dumont was living in Paris at the time, and was one of the most active "aeronauts" in Europe, having developed a series of non-rigid airships that displayed unparalleled agility, speed, endurance, and ease of control.

During late 1905 and early 1906, French aviation authorities offered prizes for the first heavier-than air machines to be flown for 25 m (82 ft) and for 100 m (330 ft) in order to promote the development of heavier-than-air aviation in France. At around that time, while watching the speedboat races on the Côte d'Azur, Santos-Dumont noticed that the Antoinette engines made by Léon Levavasseur, were both powerful and relatively light in weight.

Putting all this together, Santos-Dumont had a Hargrave-cell biplane, powered by an Antoinette engine built. The work was carried out in secret; known only to his team of mechanics and craftsmen. The wings were at the very back configured with dihedral, each wing made up of three cells. The 24 hp (18 kW) Antoinette engine sat between the wings in a pusher configuration at the extreme rear of the fuselage, with the pilot's compartment (where the pilot stood) immediately ahead. A movable cell at the nose, actuated by cables, originally manufactured for church-tower clocks, allowed for steering and altitude adjustments. This forward-mounted-mini-wing layout would later come to be called a "canard". The structure of the Santos-Dumont biplane was made of bamboo, covered with Japanese silk, and joints made of aluminum, a very rare material at the time due to the electrolytic process to refine and mass-produce it having only been adopted less than 20 years earlier.

The 14bis at the Chateau de Bagatelle grounds, under the envelope of Santos-Dumont's No.14 airship.

The aircraft was transported from Neuilly, where it was built, to the nearby Bagatelle chateau's expansive grounds in the Bois de Boulogne, where it could be tested for its initial aerodynamic behavior. In order to simulate flight-like conditions, Santos-Dumont attached the aircraft to the belly of his latest non-rigid airship, the Number 14. Due to this, the aircraft came to be known as the "14-bis". The forces imposed by the aircraft pulled at the airship's envelope in dangerous ways, nearly tearing it and only allowing limited control. The danger of such tests caused Santos-Dumont and his team to quickly abandon them, although some useful information was obtained that led to adjustments in the balance and weight distribution of the aircraft.

Santos-Dumont then connected a steel cable to the tops of two poles, one taller than the other, much like a zip-line or tyrolienne of today. The aircraft was hung by a rope and attached by a pulley to the steel cable. It was then pulled by a donkey until it rested by the taller pole, and then released and allowed to slide down the cable toward the lower pole. In this manner, the center of gravity of the aircraft was established and adjusted, and much was learned about its stability. Photographs of these tests show the vehicle being pulled up along the cable by the donkey back to the higher position.

By August 1906, the aircraft was transported back to Bagatelle, where Santos-Dumont performed what would be called today "fast-taxi tests". It was found that the engine was not powerful enough to safely reach flight speeds, and was replaced by a 50 hp (37 kW) Antoinette, a V-8 design capable of 1,500 rpm, designed by Leon Levavasseur, the French inventor of V-8 design powerplants in 1902. Early September saw greater speeds in ground tests, as well as a minor accident. On the 7 September 1906, the wheels left the ground during a quick flight.

Announcements were made about Santos-Dumont trying for all the aeronautics prizes. Crowds and aviation authorities gathered on the morning of the 13 September 1906. Not all the cylinders were firing during an initial takeoff attempt, but quick repairs allowed for the second run to result in a 13 m (43 ft) long flight, an altitude of about 1 m (3 ft) having been reached. This did not qualify for the prizes, but earned Santos-Dumont a great deal of attention.

The 14-bis landed at a high angle of attack, and the propeller at the back struck the ground. Repairs were undertaken. On the 23 October, after a series of engine tests and high-speed ground runs (one of which ended as one wheel came loose, but this was quickly fixed), Santos-Dumont finally pulled the 14-bis into the air. The aircraft flew for over 60 m (200 ft) at an altitude of about 3 m (10 ft)}. This earned Santos-Dumont the first of the aviation prizes, 3,000 francs for a flight of 25 m (82 ft) or more.

The aircraft required more repairs, as the landing had slightly damaged it, but even so Santos-Dumont announced that he should be ready to attempt the 100 meters prize on 12 November. The 14-bis was repaired, and ailerons were added to the middle of each outermost wing cell, somewhat similar to the aileron layout later used in the Curtiss Model D Pusher). These ailerons, hinged about their center of gravity with their axes running through the midpoint of the outermost wing bay's forward interplane struts, were actuated by cables attached to the shoulders of the pilot's flightsuit. Movement of the shoulders thus actuated roll control, very close in function to the similar seat-hinged "shoulder cradle" used on examples of the 1909-10 Curtiss Model D,^[2] and to the hip-movement roll-actuation control on the Wright Flyer.

On the morning of 12 November 1906, the aviation community of France assembled at the Chateau de Bagatelle's grounds to witness Santos Dumont's next attempt. As Santos-Dumont allowed the 14-bis to run down the field, a car drove alongside, from which Henry Farman would drop a plate out of the car each time he observed the wheels of the plane to leave the ground or to touch down again. The first attempt saw a 5 second flight of about 40 m (130 ft) around 40 cm off the ground, and the second saw two brief flights of 40 and 50 m (160 ft). A hurried landing due to the proximity of some trees after this second attempt damaged the wheel axles, and these were fixed during a lunch break. In the afternoon, further flights were of 50 meters and then 82 m (269 ft) (achieving about 40 km/h), this one interrupted by the proximity of a polo barrier. As the sun set, Santos-Dumont attempted one more flight. In order to ensure he would not hit spectators, who by this time were present all over the field, he pulled up flying over them. After 22 seconds, he cut the engine power and glided into a landing. He had flown for 220 meters (over 700 ft), qualifying for the second aviation prize offered for heavier-than-air-aircraft, 1,000 francs for a flight of 100 meters or more.

This 220 meters length flight was the last recorded flight of the aircraft.^[3] The next notable Santos-Dumont flight was 200 meters a year later, on a different model of biplane, this time with a rear rudder.^[3]

14-bis vs. Wright Flyer

14-bis on a French postcard

Photographs of Wright Flyer II, 1904 (top), and Flyer III, 1905 (bottom).

Controversy exists between supporters of the Wright Brothers and Santos Dumont about which aircraft, the 14-bis or Wright Flyer, was the first true airplane.

The 1903 Wright Flyer used a launch rail and undercarriage skids. After 1903 the Wrights added a catapult to assist most takeoffs of their 1904 and 1905 airplanes. The Santos-Dumont 14-bis did not use a catapult and ran on wheels.

The Fédération Aéronautique Internationale ("International Federation of Aeronautics"), founded in France in 1905 to "regulate the sport of flying", keeping track of aviation records and other aeronautical activities in the Western world, stated among its rules that an aircraft should be able to take off under its own power in order to qualify for a record. Therefore, some claim the 14-bis must be considered the first operational fixed-wing aircraft. Supporters of the Wright brothers emphasize that their aircraft made controlled, sustained, maneuvering flights a few years before Santos Dumont made his first takeoff.

A letter from Wilbur Wright to French Army Captain Ferdinand Ferber, says:

We had already seen by the picture in the New York Herald that the plane rests on three wheels and we deduce from this that Mr. Santos Dumont, in order to effect his take-off, has first to make a run over a long level field. With the aid of the starting-off pillar that we use, Orville and I speedily go right up into the air in a much more practical fashion... We are sure to find a lot in our favor if we come to exhibit in France; but the voyage and the transportation of the machine and the pillar cost much more money than the two poor mechanics can afford to spend; also, dear Captain Ferber, if French experts, under your management, desire to come to Dayton, we will give them a demonstration of the machine in a neighboring field, flying for five minutes in a complete circle and let them have an option of the performance and release of the machine, for $50,000, cash down.^[1]

Model of 14-bis

Both aircraft made free, manned, powered flights. Authenticated written and photographic documentation by the Wrights shows that they made fixed-wing flights before Santos Dumont. Official records and motion picture documentation show that the 14-bis achieved unaided takeoff on wheels; Santos Dumont supporters claim that Flyer takeoffs were not unaided. Patriotic pride heavily influences opinions of the relative importance and practicality of each aircraft.

Specifications (14-bis)

Replica of 14-bis, Santana, São Paulo, Brazil

Data from www.aviafrance.com^[4]

General characteristics

• Crew: one pilot
• Length: 9.70 m (31 ft 10 in)
• Wingspan: 11.20 m (36 ft 9 in)
• Height: 3.40 m (11 ft 2 in)
• Wing area: 52 m² (560 ft²)
• Loaded weight: 300 kg (661 lb)
• Powerplant: 1 × Antoinette 8V V-8 piston engine, 37 kW (50 hp)

Performance

• Maximum speed: 40 km/h (25 mph/21 kts)
• Range: more than 220 m (720 ft)demonstrated
• Wing loading: 5.7 kg/m² (1.2 lb/ft²)
• Power/mass: 0.12 kW/kg (0.075 hp/lb)

See also

Related development

Santos-Dumont Demoiselle

Aircraft of comparable role, configuration and era

• Wright Flyer
• Blériot III
• Blériot V
• Voisin-Farman I

References

Notes

Bibliography

• Gray, Carroll F. "The 1906 Santos-Dumont No. 14bis". World War I Aeroplanes, Issue #194, November 2006, pgs. 4-21.
• Joao Luiz Musa, Marcelo Breda Mourao, and Ricardo Tilkian, Eu Naveguei Pelo Ar ("I Flew Through the Air") 2003
• Alberto Santos Dumont A Conquista Do Ar ("The Conquer of the Air") 1901
• http://www.santosdumont.14bis.mil.br/
• http://www.thefirsttofly.hpg.ig.com.br/pioneer2.htm
• Hippolyto Da Costa, Fernando. Alberto Santos-Dumont: The Father of Aviation. transl: Soares, Hercillio A. VARIG Maintenance Base, Rio: 1973.
• Lins de Barros, Henrique. Alberto Santos-Dumont. Associacao Promotora Da Instrucao, Rio de Janeiro: 1986.
• Tobin, James. To Conquer the Air: The Wright Brothers and The Great Race for Flight. Free Press, New York: 2003.

External links

Wikimedia Commons has media related to 14-bis.

• Santos-dumont.net