The rotary engine was an early type of internal combustion aircraft engine, used mostly in the years shortly before and during World War I. By the early nineteen twenties the rotary aircraft engine was becoming obsolete, mainly because it could not operate efficiently at speeds greater than approximately 1600 RPM.
In concept, a rotary engine is simple. It is a standard Otto cycle engine, but instead of having an orthodox fixed cylinder block with rotating crankshaft as with the radial engine, the crankshaft remains stationary and the entire cylinder block rotates around it. In the most common form, the crankshaft was fixed solidly to an aircraft frame, and the propeller simply bolted onto the front of the cylinder block.
The effect of rotating the bulk of the engine’s mass was an inherent large gyroscopic flywheel effect, smoothing out the power and reducing vibration. Vibration had been such a serious problem on other conventional piston engine designs that heavy flywheels had to be added. Because the cylinders themselves functioned as a flywheel, rotary piston engines typically had a power-to-weight ratio advantage over more conventional engines.
Like radial engines, rotaries were generally built with an odd number of cylinders (usually either 7 or 9), so that a consistent every-other-piston firing order could be maintained, providing smooth running.
Here are posts about airplanes powered by rotary engines.
The image is a Nieuport 17
The French answer to the Fokker Eindekker was the Nieuport 11, equipped with the 80 horse-power Le Rhône (later the 110 horse-power), and armed with a Lewis gun, mounted on the top plane and shooting over the propeller. The machine was superior to the Fokker — all WWI pilots agreed [...]
The original Voisin type was soon replaced by the type “Bordeaux,” quite different from the original in controls and structure. There were several innovations on this machine, notably the Gnome rotary engine of 11 cylinders set like the spokes of a wheel.
The under-carriage and tail-booms and much of the understructure was made of steel [...]
In June, 1909, Roger Summer purchased a biplane constructed by Henri Farman, and on July 3d he made his first flight. Scarcely a month later he held the world’s record for duration of flight, having flown continuously for two and a halt hours. His sudden jump into the ranks of the [...]
The 1910 Paulhan biplane, actively discussed in aviation circles, was remarkable only for the strength and elasticity of its structure, and the ease with which it could be packed and shipped. Louis Paulhan, whose great exploits as an aeroplane pilot were well known, made a happy combination of a new type of [...]
One of the first machines designed by M. Goupy was a triplane with-a rear stabilizing cell, built for him by the Voisins and flown for short distances in the spring of 1908. The Goupy biplane, built in the Bleriot factory, resembled the Bleriot monoplanes in all the important features of its [...]
Henri Farman on this machine established the world’s record for duration of flight, when on December 18th, 1910, he flew continuously for almost eight hours and a half. This achievement was made possible by the great weight-lifting capacity of this type, enabling him to carry almost 450 pounds of fuel in [...]
Louis Breguet experimented with airplanes for many years at Douai, France, and gradually evolved, step by step, one of the best of the early flying machines. It is interesting to note that the first successful helicopter to lift a man was built by him and M. Richet in 1907, the total weight [...]
In 1910, Roger Sommer brought out a monoplane that followed regulation lines, but was exceptionally strong. In this machine M. Sommer at Douzy made many creditable flights within months of its introduction. The general aspect suggested a Bleriot fuselage mounted on a biplane chassis.
Top Speed: 54 m.p.h.
Engine: 50 horse-power seven-cylinder Gnome
Wingspan: [...]
The 1909 R. E. P. monoplane was considered by many to be one of the most perfect types of aeroplanes. Great finish was exhibited in its construction and form, but due probably to motor troubles it never was flown for any great length of time. M. Pelterie, the designer, was one of [...]
78 miles per hour!
In 1911, at the third competition for the Gordon Bennett trophy in Eastchurch, England, an American aviator, Charles Weymann, won the cup while flying an extraordinary new monoplane – the Nieuport II. With an overall speed of 78 MPH, but allowing for turns, he must have done around 90 miles an hour [...]
