Santos-Dumont 14-bis

From Freepedia

The 14-bis, also known as Oiseau de proie (French for "bird of prey"), was an early airplane designed and built by Brazilian inventor Alberto Santos-Dumont. In November 12 1906, in Bagatelle, France, it performed what is widely credited as the first fully unassisted takeoff (meaning, with no help from a catapult) and flight by a heavier-than-air aircraft. It was also the first flight of any heavier-than-air craft in Europe (or outside of the United States, for that matter).

Image:14bis2.jpg

Conception, Development, and Initial Tests

In June of 1905, Gabriel Voisin tested a glider by having it towed by a fast boat down the Seine. The glider's wing configuration was made up of Hargrave cells, a box-kite-like structure that allowed for great lift and structural strength with minimal weight. Voisin was towed into the air and flew for over 500 feet as the boat pulled him and his aircraft. In the aviation-crazy Paris of the early 1900s, this established the Hargrave cells as a configuration to be developed into heavier-than-air aircraft, not simply into kites. Santos Dumont lived in Paris at the time, and was by then one of the most active "aeronauts" in Europe, having developed a long series of dirigibles that displayed unparalleled agility, speed, endirance, and ease of control.

During late 1905 and early 1906, French aviation authorities, seeing the rapid development in aviation at the time, offered prizes for the first heavier-than air machines to be flown for 25 meters and for 100 meters. Ferber, a captain in the French army, was experimenting with gliders and kept in touch with Chanute and with the Wright brothers. Voisin teamed up with Louis Bleriot to develop the boat-towed glider into an airplane.

At around that time, while watching the Cote D'Azur speedboat races, Santos Dumont noticed that Antoinette-type engines, made by Levavasseur, offered great power and were quite lightweight.

Putting all this together, Santos Dumont designed and built a Hargrave-cell biplane powered by an Antoinette engine. This was originally done in secrecy, only known to his team of builders and craftsmen. The wings were at the very back configured in a dihedral, each wing containing three cells. The 24hp Antoinette sat between the wings, with the pilot's compartment immediately ahead (where the pilot stood), and with the pusher-propeller immediately behind. 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" (after a Bleriot aircraft of the same layout was said to look like a duck. This name is still used to describe aircraft with wing-like surfaces placed near the nose, whether or not they are duck-like). The structures of the Dumont biplane were made of Bamboo, with Japanese silk surfaces, and joints made of aluminum, a very exotic material at the time.

The aircraft was transported from Neuilly, where it was built, to Bagatelle, where it could be tested. In order to simulate flight-like conditions, Dumont attached the aircraft to the belly of his latest dirigible, the Number 14. Due to this configuration, the airplane came to be known as 14-bis. The forces imposed by the airplane pulled at the dirigible in dangerous ways, nearly tearing it and allowing for limited control. The danger of such tests caused Dumont and his team to quickly abandon them, although some constructive information was obtained that led to adjustments in the balance and weight placement of the airplane.

Santos Dumont then connected a steel cable to the tops of two tall poles, one taller than the other. 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 towards the lower poll. 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 airplane being pulled up along the cable by the donkey back to the higher position. This gives the appearance that the airplane was tested while being pulled by a donkey, which is not accurate).

By August 19060, the airplane was transported back to Bagatelle, where Dumont performed what we would today call fast-taxi tests. The engine was found not to be powerful enough to safely reach flight speeds, and was replaced by a 50hp Antoinette, a V-8 design capable of 1500 rpm. Early September saw greater speeds in ground tests, as well as a minor accident. On the 7th of September, 1906, the wheels left the ground during an extremely quick hop.

Announcements were made about Santos Dumont trying for all the aeronautics prizes. Crowds and aviation authorities gathered on the morning of the 13th of 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-meter (43-foot) hop, an altitude of about 1 meter 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 23rd of 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 200 feet at an altitude of about 10 feet. This earned Santos Dumont the first of the aviation prizes, 3000 francs for a 25-meter-or-greater flight.

The airplane required more repairs, as the landing had again damaged it, and Santos Dumont announced that he should be ready to attempt the 100-meter prize on November 12th. The 14-bis was repaired, and ailerons were added to the middle of each outermost wing cell (similar to the aileron layout later used in the famous Curtiss Model D Pusher). These ailerons were actuated by cables attached to the pilot's flightsuit at the shoulders. Movement of the shoulders thus actuated roll control, similarly to the hip-movement roll-actuation control on the Wright Flyer.

On the morning of November the 12th, 1906, the crowds gathered. In a surprise to nearly all there, Voisin also brought a biplane that he and Bleriot has built, and also powered by an Antoinette. Voisin made several takeoff attempts, until one of them damaged the airplane such that it could not be tested further before being extensively repaired.

As Dumont allowed the 14-bis to run down the field, a car drove alongside, and Henry Farman would drop a plate out of the car each time he observed the wheels of the airplane to leave the ground or to touch down again. The first attempt saw a flight of 40 meters, and the second saw two brief flights of 40 and 50 meters. A hurried landing after this second attemp (rushed due to the proximity of some trees) damaged the wheel axles, and these were fixed during a lunch break. In the afternoon, further flights were of 50 meters and then 82 meters. As the sun set, 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 flew at an altitude of 4 meters. After 22 seconds, he cut the engine power and glided into a landing. He had flown for 220 meters, or over 700 feet, qualifying for the second aviation prize offered for heavier-than-air-aircraft, 1000 francs for a flight of 100 meters or more.

The First Airplane? The 14-bis versus the Wright Flyers

Many people - most of them in Brazil - firmly believe that these flights, and not those of the Wright brothers, are the true dawn of aviation. In Brazil, Santos Dumont is known as the "father of aviation", and is the person who "invented the airplane". Depending on how you define "airplane", this view could be accurate.

The Fédération Aéronautique Internationale, founded in France at the beginning of the century to keep track of aviation records and other aeronautical activities, stated among its rules that an aircraft should be able to take off under its own power in order to qualify for a record. This meant that the 14-bis was, technically, the first airplane, since the Wright Flyer required a weight-driven catapult-rail system (in principle similar to those still used in modern aircraft carriers) to get off the ground. Even after three years of development, by the end of 1906 the Wrights still did not have an aircraft that could take off from a smooth grassy or paved surface rather than from a rail. They deserve much credit: theirs was the first heavier-than-air aircraft to fly for prolonged periods and to be fully controllable. During Dumont's short hops, the Wrights were already flying for minutes at a time in nicely controlled curves, ascents, and descents. However, Dumont fans will point out that, since the Wright's Flyers could not get into the air without being accelerated by a large contraption, they were not a practical vehicle.

(Note that this line of thought also strips away the records made in the X-1, X-15, X-43, and SpaceShip One, as all of those were dropped from larger aircraft and thus could not have broken their respective records if they had to take off unassisted from a runway. This is why the "official" speed record is held by the SR-71, and the altitude record by the unmanned Helios, as those aircraft could take off and land unassisted and still break those records).

For a complete discussion of this controversy, see this TheFirstToFly.hpg.ig.com.br page. Most telling is a letter from Wilbur Wright to captain Ferber, part of which says:

"We had already seen by the picture in the New York Herald that the airplane 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..."

Using this letter, many people argue that while the Wright Flyer may have been superior in the air, its take-off apparatus made it overly impractical to operate and transport.

One last noteworthy point in this debate is that many Brazilians discredit the Wrights' flights "because they used a catapult". Many Brazilian people believe this to refer to a device that launched projectiles, rather than a horizontal-acceleration device. Because of this, many Brazilians believe that the Wright Flyer was simply thrown up into the air and quickly fell again - not an aircraft at all, not a flying machine, simply a projectile, not worthy of any claim to being a form of aviation technology. This ignores the years of hard work, brilliant innovations, scientific testing, and unprecedented aerial control achieved by the Wrights. On the other hand, it is safe to say that there are more Brazilians who know at least something about the Wright brothers than there are Americans who will recognize Santos Dumont's name.

Opinions may vary on whether the Wright Flyers or the 14-bis was the more practical (and thus the "first") heavier-than-air flying machine, but many of these opinions - on both sides - are driven by ignorance of the truly amazing and uniquely innovative pioneering efforts of the Wright brothers and of Santos Dumont. Both designs, made independently of each other, used new technologies to achieve lift and controllability. Both could, once in the air, fly where the pilot desired. One flew first, the other could take off unassisted. These undisputed facts make the controversy a simple matter of definitions, although patriotic pride obscures these simple facts - facts which still leave room for argument over which of the flying machines was more practical.

Specifications (14-bis, original motor)

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)
• Empty: kg ( lb)
• Loaded: 300 kg (660 lb)
• Maximum takeoff: kg ( lb)
• Powerplant: 1x Antoinette engine, 18 kW (24 hp)

Performance

• Maximum speed: 30 km/h (25 mph)
• Range: km ( miles)
• Service ceiling: m ( ft)
• Rate of climb: m/min ( ft/min)
• Wing loading: 5.7 kg/m² (1.2 lb/ft²)
• Power/Mass: 0.06 kW/kg (0.04 hp/lb)

Related content

Related development:

Comparable aircraft:

Designation sequence: 11 - 12 - 13 - 14/14-bis - 15 - 16 - 17

Lists of Aircraft | Aircraft manufacturers | Aircraft engines | Aircraft engine manufacturers Airports | Airlines | Air forces | Aircraft weapons | Missiles | Timeline of aviation