The world’s strangest rotary engine is a 118-year-old French spinner that leaks castor oil everywhere – Jalopnik

Although modern engines include many modifications and improvements to the original ideas, they are usually not as interesting as the strange contraptions that engineers experimented with in the early days. Take for example the remarkable Gnome engine, which was used as a power plant in some World War I aircraft. It was introduced in 1908 by manufacturer Societe des Moteurs Gnome et Rhône, an organization founded by the French brothers Laurent and Louis Seguin.

The Gnome is considered a rotary engine, but is very different from the engine later perfected by German engineer Felix Wankel. Wankel’s creation used a triangular rotor that rotates within an oval housing, allowing open spaces to facilitate the steps of the combustion process. This would eventually become the basis of Mazda’s most famous rotary-powered car. While the Wankel engine has no cylinders, the Gnome engine does, but not in the way you might think.

The air-cooled 8.01-liter seven-cylinder Gnome Omega engine could generate approximately 50 horsepower at 1,200 rpm, although later iterations would produce more power. But wait, if there are cylinders, it can’t be considered a rotary engine, right? Well, the gnome worked by rotating the cylinders and crankcase around a stationary crankshaft. At first glance, it looks a bit like the inner frame of a wheel, except instead of spokes, there are thick, stubby cylinders spinning around. And there’s all that castor oil.

However, the gnome had some quirks that made speed control a bit unorthodox. The brothers first tried to regulate the fuel payout to allow for different engine speeds, but that didn’t work. They tinkered with the use of the camshaft timing, but its complexity ultimately negated one of the Gnome’s main advantages: its simplicity. Ultimately, the simplest approach was a simple on-off ignition: the gnome essentially had two states: on or off.

Various iterations of the engine were eventually installed in many aircraft, including Sopwiths, Nieuports and Moranes. In fact, according to the National Air and Space MuseumBy the time World War I was over, more than 20,000 gnomes in different variations had been built. Because powered flight was still relatively new, airplanes naturally looked very different than they do today. Just look at Boeing’s first airplane, a small seaplane called the B&W.

Even worse, the gnome used castor oil for lubrication because it burns clean, and centrifugal force caused the total-loss oil system to spew out unburned oil as it ran. Combine that with the speed achieved in flight and the pilots in the open cockpits of those early aircraft would become covered in an oily residue of engine fluid – which can be embarrassing in other ways as well, since castor oil is a laxative.

The Gnome’s design limited its potential, especially in the amount of power possible, as it could not realistically be made much larger. It certainly could never be adapted for an automotive application, and other aircraft engine configurations continued to outperform the Gnome’s capabilities. Although it was a miracle considering the technology at the time, the gnome now lives in the pages of history, save for a few hobbyists who have built replicas. However, the gnome is far from the only bizarre power plant design from the 20th century; the weirdest engine you will read about today is the Sarich Orbital.