Alexandre Goupil's Sesquiplane

Alexandre Goupil’s design for a flying machine. The craft is a sesquiplane, meaning it has two sets of wings, one much smaller than the other. Goupil envisioned a steam engine inside the bulbous body, powering a single propeller at the front.

Alexandre Goupil was a French engineer, best known for designing and testing a flying machine in 1883. The machine was a sesquiplane, which is a plane with two sets of wings, one much smaller than the other. It was to be powered by a steam engine housed in a bulbous, streamlined body, which powered a single propeller at the front of the craft. The machine had a wingspan of 6 meters (20 feet), and had space for an operator to stand below the body. The machine rested on two wheels while on the ground, and the operator stood on two pedals connected the front wheel. It’s a rather simple design, except for the steam engine. It would’ve been quite difficult to build a body that could support the engine, which weighted approximately 1000 pounds, and the machine would require a method to re-fuel the engine with coal or wood.

Goupil’s original design for his sesquiplane. Here, the operator sat inside the body, along with the steam engine that would power the propeller.

Goupil’s final design for his sesquiplane. The overall concept remained the same, but the design was streamlined and the wing geometry was simplified.

Despite these complications, Goupil ended up building an initial version that was unpowered, and he made successful test flights with it. One such test produced enough lift to raise the machine and two pilots into the air under a 22.5 kph (14 mph) wind. This is impressive for a machine without a power source, which means Goupil was onto something. Unfortunately, for reasons unknown he didn’t pursue further test flights.

Around a year later in 1884, Goupil published La Locomotion Aérienne, which cataloged his knowledge and observations of flight, including the study of birds, air flow, and wing design. He also included past flying machines with descriptions of what worked and what didn’t. The book was well received, and it no doubt was used by others who would pursue flight after him.

Glenn Curtiss’ 1916 version of the ‘Goupil Duck.’ Curtiss built this machine after a patent dispute with the Wright Brothers.

One such individual who learned from Goupil’s work was Glenn Curtiss, who built a version of Goupil’s flying machine, called the Goupil Duck. Curtiss built the machine because of a patent dispute with the Wright Brothers over three-axis control. The Goupil Duck flew test flights in 1917, and the patent dispute ended shortly thereafter due to the First World War.

Read more about other ideas for flying machines here.


[1]: Goupil, Alexandre. La Locomotion Aérienne. Charleville: A. Pouillard, 1884.