Anzani 20-Cylinder Aircraft Engine

By William Pearce

Alessandro Ambrogio Anzani was born in Gorla, near Milan, Italy on 5 December 1877. As a young child, Anzani was exposed to the fundamentals of engineering and mechanical design by working at his uncle’s bicycle shop in Monza. In 1899, Anzani attended a bicycle race in Milan where he met and became friends with Frenchman Gabriel Poulain, the future cycling world champion. Poulain was impressed with Anzani’s mechanical aptitude and invited him to France.


Ads for the Anzani 20-cylinder engine first appeared in April 1913, and the ad above is from July 1913. The list price for the engine in 1914 was £1,072. (image via

Anzani moved to Saint-Nazaire, France in 1900, and with Poulain’s assistance, he competed in a few bicycle races. Anzani soon moved to Paris and was hired by Compagnie des Automobiles et Cycles Hurtu (Hurtu Automobile and Cycle Company). Hurtu originally manufactured sewing machines but was reorganized in 1899 to focus on the construction of automobiles and motorcycles. While at Hurtu, Anzani was exposed to the fine details of internal combustion engines, and he began racing motorcycles in 1903.

Anzani soon left Hurtu to focus on motorcycle racing. In 1905, Anzani became the first motorcycle world champion, a feat that was achieved on an Alcyon motorcycle powered by a Buchet engine that Anzani had prepared himself. In the 1905–1906 time period, Anzani was closely allied with the Buchet company, even working on and “piloting” their propeller-driven Aéro-motocyclette.


Rear view of the 20-cylinder engine shows its two magnetos. Note the bifurcated “Y” exhaust stacks and the rear carburetor under the engine.

Anzani’s motorcycle racing exploits had made him a rich man, and in December 1906, he founded La Société des Moteurs Anzani (The Anzani Motors Company) to manufacture motorcycle engines. The new company settled in Courbevoie, near Paris, France, and began manufacturing single and V-twin engines, which were similar to the respective Buchet types with which Anzani was previously involved. Around 1908, a three-cylinder engine was available. The three-cylinder engine was of a W or fan configuration; it had a center, vertical cylinder, and the two other cylinders were angled at 60 degrees.

Anzani engines quickly established themselves to be light and reliable. Such engines caught the attention of early aviation pioneers, who desperately sought such power plants. One of the first to order an Anzani engine to power an aircraft was Louis Blériot, who used the three-cylinder, 45 hp (34 kW) engine to make the first crossing of the English Channel by air on 25 July 1909. After Blériot’s success, Anzani received numerous orders for engines to power aircraft, which resulted in the company redirecting its focus from motorcycle engines to aircraft engines. In late 1909, La Société des Moteurs Anzani was reorganized as Anzani Moteurs d’Aviation (Anzani Aviation Engines).


Frank Coffyn with the Azani 20-cylinder engine purchased by Robert Collier to power his Burgess Company Model L Flying Boat. Note the front carburetor under the engine and the induction pipes leading from the front crankcase chamber to the cylinders.

The Anzani company quickly went to work creating a large line of aircraft engines. In addition to the previously offered V-twin and three-cylinder fan engines, single-row three-, five-, and seven-cylinder radials were built. In the never-ending search for more power, the new single-row engines were used as a basis for two-row engines with six, ten, and 14 cylinders. In 1912, the two-row, 10-cylinder engine was used to develop a four-row, 20-cylinder radial, one of the most powerful engines of the time.

The Anzani 20-cyinder air-cooled radial was constructed in a similar fashion as other Anzani engines. The direct-drive engine consisted of four rows of five cylinders. However, the front two rows and the rear two rows were essentially paired together. The engine appeared more as a two-row radial with 10 cylinders in each row. The cylinders of a single row were separated by 72 degrees, paired rows were separated by 36 degrees, and all cylinders were separated by 18 degrees.


Coffyn stands in the Model L Flying Boat with the 20-cylinder engine mounted between the biplane’s wings. It appears the engine’s installation allowed for unrestricted access to cooling air.

The engine had an aluminum crankcase made in three parts. The central casting comprised the power section with four rows of five cylinders. The front and rear castings acted as covers and were secured to the central casting via studs. They also supported the respective ends of the crankshaft via roller bearings pressed into their castings. The rear casting also supported the accessory drives for the two magnetos. The hollow, two-throw crankshaft did not have a center support. The connecting rods for the front and rear cylinder row pairs were placed side-by-side on a common crankpin and used slipper-type bearings. The two crankshaft throws had an included angle of 162 degrees.

Under the engine, two carburetors were mounted—one toward the front and one toward the rear. Air was drawn through the carburetors and into separate chambers in the crankcase that fed the front and rear cylinder-row pairs. The air and fuel mixture was delivered from the chambers to the individual cylinders via a vertical pipe that ran along the outside of each cylinder. A single automatic (atmospheric) intake valve admitted the air and fuel mixture into the cylinder. The incoming charge was ignited by a single spark plug, and the exhaust was expelled via a short bifurcated exhaust stack. Each exhaust valve was operated via a rocker arm and push rod. The push rods were actuated via roller tappets from a cam ring. A cam ring at the front of the engine controlled the exhaust valves for the front pair of cylinder rows, and a cam ring at the rear of the engine controlled the exhaust valves for the rear pair of cylinder rows. Each cam ring had four lobes and ran at .25 crankshaft speed.


Right-rear view of the Model L provides a good view of the 20-cylinder engine in the pusher configuration. Note the extension shaft leading to the wooden four-blade propeller (made up of two two-blade units) that was 8 ft 4 in (2.54 m) in diameter.

Each of the cylinders was secured to the crankcase via two long lugs that passed through the crankcase to the cylinder head. The cylinders were made of cast iron with an integral cylinder head and cooling fins. The engine’s flat top pistons were made from cast iron. Each of the two magnetos attached to the rear of the engine fired half of the cylinders, with one magneto firing the left cylinders and the other firing the right cylinders.

The Anzani 20-cyinder air-cooled radial had a 4.13 in (105 mm) bore and a 5.51 in (140 mm) stroke. The engine’s total displacement was 1,480 cu in (21.25 L), and it produced 200 hp (149 kW) at 1,250 rpm. The 20-cylinder engine weighed 682 lb (309 kg).

The 20-cylinder engine was completed and tested by early 1913. For testing, the engine was secured in what resembled an aircraft’s frame complete with wheels and run stationary on the ground. One of the first (perhaps the first) engines was purchased by Robert Joseph Collier for use in a Burgess Company Model L Flying Boat that Collier was having built. Collier created the Collier Trophy that was first awarded in 1911 and continues to be awarded today “for the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space vehicles, the value of which has been thoroughly demonstrated by actual use during the preceding year.” The Burgess Company (or the Burgess Company and Curtis, Inc) was founded by William Starling Burgess and Greely S. Curtis at Marblehead, Massachusetts in 1910.


Robert Collier piloting the Model L over Lower New York Bay in late 1913.

The Anzani 20-cylinder engine was shipped to the United States in mid-1913 and installed in the Model L. The Model L Flying Boat was a pusher biplane that had a 41 ft 4 in (12.60 m) wingspan, was 30 ft 6 in (9.30 m) long, and had gross weight of 2,050 lb (930 kg). The aircraft’s top speed was around 75 mph (121 km/h). The Anzani engine was installed between the aircraft’s wings, and it turned a four-blade, 8 ft 4 in (2.54 m) diameter propeller via an extension shaft. The Model L made its first flight on 19 July 1913 piloted by Frank Coffyn.

Another 20-cylinder engine was part of the Anzani display at the Salon de l’Aéronautique in Paris in December 1913. Other Anzani engines displayed were the 3-, 5-, 7-, 10-, and 14-cylinder radials. The 20-cylinder engine was offered through 1915, but it seems that not many were sold. Involvement in World War I might have ended whatever limited production run the engine had. No aircraft beyond the Burgess Model L are known to have flown with the Anzani 20-cyliner. The engine in Collier’s Model L was removed during World War I and eventually given to the West Side YMCA in New York, New York around 1919 where it was used as an instructional aid.


The 20-cylinder engine in the possession of the West Side YMCA in New York circa 1919. The engine was used as an instructional aid, but it is not known what ultimately happened to the 20-cylinder engine. Note the engine’s mounting ring which could be used in tractor or pusher installations.

1914 Types Anzani Engines (1914)
A History of Aeronautics by E. Charles Vivian (1921)
Aerosphere 1939 by Glenn D. Angle (1939)
Les moteurs Anzani by Gérard Hartmann (22 February 2007)
– “Anzani Engines and the new 200 HP Model,” Flight (5 July 1913)
– “Aero Engines at the Paris Show, 1913” Flight (24 January 1914)

1 thought on “Anzani 20-Cylinder Aircraft Engine

  1. Sean O'Callaghan

    Another great article on an amazing engine. It really is impressive what some people were able to do back then. Sad to hear the engine is no longer with us.


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