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.
For World War One, the Morane-Saulnier A-1 had very modern lines and was very streamlined; it resembles small airplanes that you can see today at any general aviation airport. 1,210 were produced, but it never made a big impact at the front. Not long after its introduction it was withdrawn to serve as trainers, as [...]
The Sopwith ‘Pup’ was fast, agile, and easy-to-fly, perhaps reflecting the fact that it was developed from the personal aircraft of Harry Hawker, Sopwith Aviation’s test pilot.
Entering service in late summer of 1916, the Sopwith “Scout” (as it was officially termed) was one of the first British tractor biplanes with a synchonized machine gun. [...]
While it resembled, both in appearance and in specifications, the D.H.2, J. Kenworth’s F.E.8 was considerably less successful. But problems with the aircraft’s stability and engine development delayed its deployment at the front until August, 1916, and by then the new German Albatros D.I and D.II wholly outclassed the British pusher biplanes like the F.E.8.. [...]
Arriving at the front in February 1916, the Airco D.H.2 was fairly late in the British series of fighter pusher biplanes. A single-seater, it was considerably faster and more agile than the Vickers Gun-bus, and enjoyed some successes against the Fokkers in early 1916. But improved German models soon surpassed it. About 450 were built.
The [...]
Visitors to Britain’s Olympia Air Show in March, 1913 had the chance to see the world’s first fighter plane; called a “Destroyer,” the Vickers Experimental Fighting Biplane (E.F.B.) was the first aircraft specifically designed to shoot down other airplanes.
As their engineers had not yet figured out how to fire a machine gun though the [...]
This is the airplane that ushered in fighter combat. Before Tony Fokker fashioned his famous synchronizing gear to a machine gun so that it could fire through the prop, aerial combat was a hit-or-miss proposition. After his E.III swept the skies in 1915, air fighting developed into a deadly serious skill.
The earliest planes of [...]
Avro 504A
Avro 504B
Avro 504J
Produced by Alliott Verdon Roe, Britain’s great pioneering aircraft designer, the Avro 504 trained nearly every British pilot in the Great War; over 8,000 were built. Especially suitable for the purpose of training pilots, it was the standard training machine of the Royal Air Force. The plane’s diagnostic feature is the the [...]
On the morning of October, 5, 1914, French Sergeant pilot Joseph Frantz and mechanic Corporal Quenault in their Voisin biplane spotted a German Aviatik flying at about 3500 ft. He closed on until Quenault found the range and opened fire with a light machine gun. The Aviatik dove away, but Frantz followed, Quenault firing intermittently. [...]
The Deperdussin, along with the Bleriot and Morane-Saulnier, was another speedy French monoplane that dominated the air races in the years leading up to World War One.
A very small monoplane, designed by MM. Bechereau and Koolhoven for the Deperdussin firm to compete in the James Gordon Bennett race, proved to be the fastest machine built [...]
A stream of gasoline burst forth as Gustav Hamel flew over the Thames River on September 20, 1913. The last thing any aviator needed in a wood and cloth monoplane with a barely-covered, hot, sparking, rotary engine a few feet away was gasoline in the cockpit. It was a mortal danger for any pilot, and [...]
