MIAMI – The story of the Curtiss-Goupil Duck is a fascinating chronicle of four aviation pioneers battling it out in the early days of the industry. As we’ll see, the Duck’s capability for a heavier-than-air flight was neither experimental nor commercial.

The Wright brothers are often credited with being the first to achieve power-controlled flight on December 17, 1903. Then, in 1906, they were granted a patent for their lateral control method, which was based on wing warping, though they did admit at the time that other methods were feasible.

Goupil Duck. Photo: Public Domain

Lateral Control

Lateral control, which affects the side-to-side roll of an airplane, is, of course, a crucial aspect of keeping an aircraft in the air. The ability of an aircraft to make a controlled turn is the most obvious and visible hint to the successful adoption of any form of lateral control.

Long before the Wright brothers’ famous first flight, aviation pioneers explored and experimented with this subject of lateral control.

With their 1906 patent application, the Wright brothers hoped to gain a monopoly on manned flight, requiring anyone building aircraft to pay a royalty to utilize the patent. Wilbur Wright had a strong opinion on the matter. “it is our view that morally [and legally], the world owes its almost universal use of our system with lateral control entirely to us,” he wrote in a letter to Octave Chanute, a friend and collaborator of the Wrights, on January 20, 1910.

Wing warping is one method of attaining lateral control, altering the wing’s shape to accomplish aerodynamic effects. It has advantages and disadvantages, and it was a key component of early aircraft for a brief period, surviving as a viable option until around 1915.


Wing Warping vs Ailerons

Dutch aircraft designer Anton Herman Gerard “Anthony” Fokker was possibly the most prominent proponent of wing warping. He continued to do so throughout WWI, despite the fact that his aircraft had become outdated as a result. In 1908, aviation pioneer Glenn Curtiss sought to circumvent the Wright patent by using ailerons.

Curtiss wasn’t the first to use ailerons in manned flight. That honor goes to Robert Esnault-Pelterie in his glider of 1904. In truth, ailerons had been patented in 1868 by British scientist Matthew Pierce Watt Bolton.

Ailerons, which use moveable flaps in the wings to achieve the same results as wing warping, are a considerably more effective and simple solution to lateral control. Some even speculate that if more people were aware of Bolton’s patent, the Wrights’ 1906 patent would never have been issued.

Regardless, the Wrights sued Curtiss for patent infringement, and thus began the historic Wright brothers’ patent wars, which lasted for years. That’s a story for another day.

Souvenir postcard of the Grande Semaine d’Aviation, 1909. Photo: By Unknown author – french postcard 1909, Public Domain,

Glenn Curtiss

Glenn Hammond Curtiss, a contemporary of the Wright brothers and one of the pioneers of the United States aircraft manufacturing business, was an aviation pioneer. He began his career as a bicycle courier and racer, and then as the owner of a bicycle shop.

Curtiss became interested in motorbikes and the internal combustion engines that accompanied them as they became more popular. He started making motorcycles with his own single-cylinder engines in 1902. In 1903, he set a motorcycle land speed record of 64 mph, and in 1907, he set an unofficial record of 136.36 mph. He was, however, already active in aviation at the time.

Curtiss became a supplier of engines to Tom Baldwin, a pioneer in balloons who created the first successful power dirigible in the United States, in 1904. Curtiss joined the aerial experiment association, which was designing its own aircraft, in 1907. With his engines, he contributed to the project, and he was also one of the designers and test pilots.

Glenn H. Curtiss’s pilot license. Photo: Евгения Тихонова – National Air and Space Museum, Public Domain,

The Curtiss-Wright Competition

Curtiss was awarded US pilots license number one by the Aero Club of America on June 8, 1911, coming ahead of Wilbur Wright, who was awarded license number five. He also beat out the Wright brothers in public aircraft displays, and on July 4, 1908, he did so. Curtiss won the Scientific American trophy and the US$2,500 prize by flying 5,080 feet.

This was the first public flight of a heavier-than-air aircraft in the United States, and it catapulted Curtiss and aviation itself into the public consciousness. Some claim that Curtis did more to improve the popularity of aviation in the United States than the Wright brothers did, though innovation and entrepreneurship are not a race to be the first but to compete at every stage. It makes sense why Curtiss would want to get around the Wright brothers’ patent.

Glenn Curtiss looked for a way to prove that the Wright brothers did not invent lateral control and thus invalidate the 1906 patent when the Wright brothers’ patent fight was still raging in 1916. He needed to locate an aircraft that predated the first powered flight in 1903, one that could not only fly but also demonstrate lateral control by turning in a controlled manner.

Even with the benefit of hindsight, the Internet, and relatively easy access to patent information, this is still a daunting prospect. How could such an aircraft exist before 1903? Enter French engineer Alexandre Goupil.

A flying aircraft designed by Alexandre Goupil. The craft is a sesquiplane, which means it has two wings, one of which is significantly smaller than the other. Inside the bulbous body, Goupil imagined a steam engine driving a single propeller at the front. Image: Public Domain

Alexandre Goupil’s Monoplane

In 1883, Goupil created a bird-like monoplane glider that appeared to be stable when restrained. He was unduly excited about his new steam engine, which weighed roughly 1,000 pounds and produced 15 horsepower. However, flying the monoplane with it was not a feasible task.

Goupil did manage to fly unpowered test flights successfully. Under a 14 mph wind, one flight produced enough lift to lift the machine and two pilots into the air. This is remarkable for a machine without a power supply, indicating that Goupil was correct. Unfortunately, he did not continue further flight tests for unclear reasons.

The final design for Goupil’s sesquiplane. The general concept remained the same, but the design was simplified, as was the wing geometry. Image: Public Domain

The plane had a streamlined bird-shaped fuselage, a tractor propeller, and a horizontal tail and rudder aft. It was supported by skids. The pilots moved around on a hinged seat, controlling two stubby horizontal surfaces forward. They could be used in tandem as elevators or in opposite directions as ailerons, but their primary function was to restore natural balance rather than to bank or turn. He dubbed his machine an airplane, one of the first to do so.

Clearly, Glenn Curtiss or one of his colleagues recognized the aircraft’s potential and the possibility of installing an engine. If it could fit a steam engine, it could certainly fit a modern aircraft engine that would be lighter and deliver greater power.

The Curtiss-Goupil Duck takes to the skies. Photo: Public Domain

The Curtiss-Goupil Duck Takes to the Skies

Curtiss had a dock built using Goupil’s original patent drawings and a description in Le Local Museum Ariens at his Buffalo, New York plant. Curtiss pushed the type first on wheels rather than skids, then on floats, and finally back on wheels. The Curtiss OXX-6 engine was chosen because it weighed 600 pounds less than the steam engine proposed by Goofy and had a 100 horsepower output that was far more powerful.

The contraption took to the air for the first time on January 19, 1917, flying straight and level for the first time, then in a circle. Curtis made several important improvements to the original, as he did with his rebuilt Langley airfield – control linkages, engines, and longer wings – but the core design remained the same, proving that lateral control predated the Wright brothers’ patent by a considerable amount of time.

However, Curtiss never got to make use of his evidence that the Wights were not the first to invent lateral control. The Curtiss-Wright patent fight was settled by arbitration in 1917 as US involvement in WWI grew. The US government had convinced Orville Wright to release the patent, citing the need for combat aircraft.

Featured image: “Curtiss Goupil Duck – 1917.” [Plate also dated May 5, 1916] Public Domain. Article source: Jerry Cantlow via YouTube.