domingo, 28 de janeiro de 2024

Speculations about the Operation and Proposal of S=D # 18 - Hydroglisseur


With Number 18, Santos=Dumont not only improved the Demoiselle but also contributed to the efforts in making high-speed luxury boats a reality, alongside inventing a revolutionary hydraulic system.



Santos=Dumont went beyond enhancing the Demoiselle; he transcendentally innovated by introducing a disruptive hydraulic system. This not only challenged the conventions of the time but also paved the way for a new chapter in the evolution of aviation and aquatic means—everything started with a bold bet.

The Audacious Wager

The tireless researcher with a fertile imagination, Santos-Dumont, seemed more like an amateur of feats than of lasting successes.


After circumnavigating the Eiffel Tower with his first dirigible balloon and executing wise maneuvers in Trouville with another balloon, he immersed himself in aviation. Without abandoning other modes of aerial locomotion, he dreamed of conquering the liquid element with his hydroplane. During a historic dinner among high-profile sportsmen on July 24, 1906, Mr. Charron, perhaps influenced by the communicative warmth of the banquet, made serious and encouraging challenges:

Mr. F. Charron bet 10,000 francs against Mr. Bleriot's 2,000 that it wouldn't be possible to reach 100 km/h on the water with any apparatus before April 1, 1908, covering only 1 km but in both directions, and the average of the two experiments would be considered. Arbiter: Mr. René de Knyff.

Mr. F. Charron bet 50,000 francs against Santos=Dumont's 5,000 that the latter couldn't achieve 100 km/h on the water before April 1, 1908, with the same timing method as before.

Mr. F. Charron and Marques de Dion bet 5,000 francs against Archdeacon and Santos-Dumont that they wouldn't see an airplane fly a distance of 500m without touching the ground before February 1, 1908.

René Doncières – "Les nouveaux Santos=Dumont," La Nature, n. 1796, October 26, 1906, p. 344

Santos-Dumont piloting his Number 18 - Hydro Glisseur. His hydraulic steering system anticipated Francis Devis' invention by more than 10 years.

The Santos=Dumont #18 Hydro glisseur wasn't just an isolated experiment; it was a crucial milestone that provided essential insights for the subsequent development of Demoiselle and, by extension, modern airplanes. Conceived to study the interactions between wings and water, Number 18 initiated a significant chapter in aviation history.

Unfortunately, Dumont didn't win the bet.

Speculations on Operation and Piloting

The analysis of Number 18 raises fascinating speculations about its operation and piloting. Given Santos-Dumont's distant position from the engine, intriguing questions arise about the controls and onboard systems.

In this photo, the compressor seems to be at the stern, protected by a cover (possibly made of wood).

The suggestion of hydraulic controls for the submerged fins is an innovative approach, providing an efficient means to control the vessel's elevation in the water.

Mysterious Contraption

In this photo, we see the two volumes covered with canvas, the 100hp Antoniette engine, and the mysterious object just below the engine.

Santos=Dumont conducted various experiments with the Hydroglisseur, and by observing photos and videos from that time, a mysterious device becomes apparent. This device is often covered with a canvas or wooden casing, sometimes located under the 16-cylinder, 100hp Antoniette engine, occasionally covered with a canvas with lateral stripes. Other times, the mysterious device appears at the stern, just behind Dumont's saddle. What could it be?

The mysterious device seems to be an air compressor with outlet towers, valves, cables (and perhaps a centrifugal regulator). It is likely a hydraulic system where pistons and actuators move and hold the fins in a diving and rising position, allowing Dumont to conduct buoyancy experiments.

In the video, it's evident that it's some kind of air compressor, seemingly not used to inflate the floating pontoons, as they are structured. Nor is it for circulating water in the radiator since a centrifugal governor is observed, a characteristic part of steam engines, with two spheres gently spinning, typically used to balance force in gas outlets.

The mysterious device is likely a hydraulic system, with a pump propelling gases into a cylinder transmitting pressure to pistons and actuators. This aligns with the advanced function of controlling altitude on the water's surface.

In this October 6, 1907, Le Pèlerin 1605 photo, we can clearly see what appear to be air pistons acting as actuators on the stern fin.

Manipulating the fins (rudders) to adjust the ascent or descent, according to Dumont's control, involves complex hydraulic components, revealing a high degree of sophistication in the design. Perhaps, it was one of the first hydroplanes to rise in the water using hydrofoils to achieve greater speeds.

By examining the pistons and cylinders, we can extrapolate the operation of the control system for the fins on Santos=Dumont's Number 18, based on a clever hydraulic system (from the photos, it could well be a 'Bowden cable' system, a mechanism that uses a thin wire filament moving inside a flexible outer casing, similar to bicycle brakes).

Let's continue with the hydraulic system, in which a cylinder containing pressurized fluid is central to the operation, strategically positioned valves play a crucial role in regulating the flow of hydraulic fluid. When Dumont wants to adjust the position of the fins, he precisely operates these valves, opening and closing as needed.

observing the pistons and cylinders it is possible to extrapolate the functioning of the fin control system in Number 18 by Santos=Dumont, based on an ingenious hydraulic system. In this system, a cylinder containing fluid held under pressure is central to the operation, strategically placed valves play a crucial role in regulating the flow of hydraulic fluid. 

In the diagram above, we see how from his seat Dumont could have controlled the submerged ailerons to understand and master hydrodynamic forces, similar to aerodynamics:

Diving Position

To position the fin in a diving position, Dumont skillfully manipulated the valves, opening and closing them precisely to control the flow of hydraulic fluid through the cables to the opposing pistons, generating targeted pressure. This resulted in a coordinated movement of the fins to the desired diving position.

Ascending Position

When Dumont decided to raise the fin's position, he reversed the position of the valves to direct the hydraulic fluid in the opposite direction through the cables to the pistons. This reverse action creates pressure that propels the pistons to lift the fins, allowing the aircraft to return to the surface or reach a desired ascending position.

But which fin moved? Front or rear fin?

The proposal to use a piston to generate pressure and control the front hydrofoils (fins) is ingenious. The integration of a hydraulic system would drive a piston, which in turn would raise the front fin.

Assuming a system to lift the vessel to move the front fin, the simplified tubes painted in red demonstrate the pressure lines controlled by Dumont to lift and maintain the front fins' position.

Observation of the photos is crucial for a more accurate understanding. The rear fins seem to have a tilt actuator, suggesting that these would be the moving parts influenced by the proposed hydraulic system. Therefore, the movement could be centered on the rear fins, allowing the adjustment of the vessel's tilt in the water through the piston driven by the hydraulic system.

Different from the photo above, here we see a system to lift the vessel to move the rear fin. The simplified tubes painted in red move the rear fin in the diving direction, forcing the stern to lower and the bow to rise.

The Marvelous Antoinette Engines

The power-to-weight ratio of these engines enabled the first flight of a heavier-than-air craft in 1906 (read the article).

In May 1906, Gastambide and Levavasseur founded the Antoinette company (named after Gastambide's beautiful daughter) in Puteaux, located at 28, rue des Bas-Rogers, for the mass production of V8 and V16 engines. Louis Blériot, in search of an engine, contributed funds and was appointed the company's vice president.

The lovely Antoniette Gastanbide, daughter of one of the partners, gave her name to this engine factory that contributed significantly to the history of aviation and navigation. The company's ads highlighted the excellent power-to-weight ratio of the engine, which could be carried on the shoulders with ease, enabling Santos=Dumont's first heavier-than-air flight.

In just two months, a V8 engine with 50 hp at 900 rpm was developed in the small Puteaux factory. This time, the engine operated correctly, and several units were built (around a dozen). Santos-Dumont successfully used it in his first flights in Bagatelle in October and November 1906, with numbers 17 and 18.

Practically all French aviators adopted this engine, driven by Dumont's successes. The engine was surprisingly light compared to the power it delivered - in an advertisement from that time, a man is depicted carrying a 16-cylinder engine block on his back without much effort.

Levavasseur introduced a new V8 engine with 24 hp, weighing only 36 kg, and a V16 with 100 hp, weighing 150 kg.

Controls of S=D #18

Extrapolating how Dumont piloted his hydroglisseur implies assuming that the hydraulic system described above was indeed used, given that the assumptions above are correct.

Santos=Dumont, piloting his Hydroglisseur #18, demonstrated mastery in using the complex hydraulic system to control the elevation, direction, and tilt of the vessel on the water. Positioned at the stern, the pilot handled the steering wheel similar to the automobiles of that time, like the 1907 Renault.

Initiating the aquatic experience, Dumont started the engine with a button located in front of the steering wheel. The propeller's gearing was skillfully performed through a lever positioned to his left. The aviator (now a ship captain) not only navigated the waters but also elevated himself to a new level of control by exploring the hydraulic system.

To steer the vessel to the right or left, Dumont adjusted the altitude on the water's surface using the steering wheel connected to a system that activated pistons. This system, analogous to the wings of an airplane, moved the port and starboard fins. When desiring to turn right, the pilot adjusted the left fin for elevation and the right fin for descent, providing refined control over the Hydroglisseur's trajectory (possibly this control was not so efficient, as in some photos Dumont appears to be manipulating a tail rudder).

Thus, Santos=Dumont navigated not only on the waters but shaped his course with precision, exploring the nuances of the innovative hydraulic system he introduced.


It's important to note that the tests with the hydrofoils were conducted when #18 was towed by a high-speed boat.

Hydroplanes and Hydrofoils

Needless to say, Dumont had not just 20 inventions because, considering all the solutions and achievements conceived, the number of creations easily surpasses 300.

Above left, a drawing of the first British patent granted in 1869 to Emmanuel Denis Farcot, of his hydroplane with lateral fins; on the left, the test of the Fenaille hydroplane on the Seine River in the late 1920s, with an aerial propeller of 5m x 2.25m. Below, the modern W-Foil, reaching a constant speed of 40 knots, with incredible fuel consumption ranging from 7 to 10 gallons per hour, can keep the unique laser-cut fir wood hull above the surface. The company plans to organize classic races with the twelve units currently in production.

Both the hydroplane and hydrofoil had been patented during Dumont's time; however, he conducted the first practical tests on existing ideas. The first evidence of a hydrofoil on a ship appears in a British patent granted in 1869 to Emmanuel Denis Farcot, a Parisian, who "by adapting to the sides and bottom of the vessel a series of inclined planes or wedge-shaped pieces, which as the vessel advances will have the effect of lifting it in the water and reducing drag."

Italian inventor Enrico Forlanini began working on hydrofoils in 1898 and used a "stair" system of fins. Forlanini obtained patents in Britain and the United States for his ideas and designs.

With Number 18, for instance, Dumont conceived and tested dozens of devices and solutions; the hydroglisseur is undoubtedly a strong supporter of this argument. It was a true package of inventions, including the hydraulic system for the movement and stability of the fins, the hydrofoil to reduce water drag and achieve higher speeds, and the direction control with hydraulic pistons, among many other solutions that unfortunately got lost in time.

After Dumont's contributions, other pioneers also incorporated hydrofoils into their vessels, playing a crucial role in the evolution of this means of transportation.


Auguste Tellier founded 'Les Chantiers Tellier' in 1870, a shipyard for luxury, high-speed boats in La Rapée, Paris.

From the pioneering work of Les Chantiers Tellier to contemporary creations like modern hydrofoil racing boats, hovercraft gliding on an air cushion with rear propellers, and airboats maneuvering through the shallow waters of the Everglades, technology has evolved considerably.

The current applications of hydrofoils range from passenger transport to competition boats, highlighting the versatility and efficiency of this technology over the years.

But in the end, who broke the 100 km/h record on water?

Santos=Dumont's initiative to attempt breaking the 100 km/h record on the Seine River with Hydroglisseur #18 was notably ahead of his time, even considering his genius and the incredible 100hp Antoinette engine, the most advanced and lightweight of that period.

Don Aronow not only broke the 100 km/h record in 1967 but also created the Magnum brand, a legendary icon in the high-speed luxury boat market.

The real achievement of the challenge to reach 100 km/h on water occurred in 1967 when Don Aronow piloted his 27-foot Maltese Magnum with two MerCruiser outboard engines of 255 HP each in the Miami-Nassau Power Boat Race. He reached an incredible speed of 58.4 knots (approximately 108.15 km/h) in waves of 2 to 3 meters high, securing the record.

It's fascinating to observe Santos=Dumont's rare smile captured alongside Edna Powers in the photo of No 18. This moment speaks volumes about the unique joy Dumont found in his invention, which is my favorite, a striking testament to his passions

Don Aronow was an extraordinary figure, a master boat builder behind legendary brands like Magnum, Cigarette, and Donzi. The movie "Speed Kills" with John Travolta highlights his achievements in the world of high-speed boats, although it dramatizes some events, such as Aronow's tragic death, presented in the film with exaggerations and alterations for added drama.


The Number 18 is undoubtedly my favorite invention of Santos-Dumont, mainly because it conveys the feeling of incredible super-fast luxury boats, as well as its bold and unique design, which likely inspired George Lucas in conceiving the Naboo N-1, piloted by Anakin Skywalker in the fourth film of the franchise, "Star Wars Episode I: Phantom Menace."

Is it so?

The Santos-Dumont Hydroplaner #18 remains a symbol of its creator's ingenuity and audacity, inspiring not only aviation but also contributing to the evolution of hydroplanes and amphibious vessels. 


As we explore the origins and speculations surrounding Number 18, we gain a deeper appreciation for the innovations that shaped the course of aeronautical and naval history.

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