Anzani 10-cylinder

Anzani
Company type	Private
Industry	Aerospace engineering
Founded	1913
Products	Aircraft engines

The Anzani 10 was a 10-cylinder air-cooled radial engine introduced in 1913. It powered both prototype and production aircraft, including reconnaissance planes like the Caudron G.3, bomber and trainer variants such as the Caudron G.4, and the initial production Cessna aircraft, notably the Model AA.

Design and development

Starting from his initial 3-cylinder 'W' configuration motorcycle engine—famously used by Bleriot during his 1909 Channel flight—Anzani progressed to a three-cylinder 'Y' radial design, followed by a 6-cylinder double-row radial engine.

By 1912, Anzani had created the Anzani 10, a double-row radial engine with 10 cylinders of varying sizes, air-cooled for efficiency. One high-performance variant produced approximately 110 hp (82 kW) from a displacement of 12.1 litres; a British-manufactured version achieved 125 hp, while a smaller displacement model of 8.27 litres generated around 80 hp (60 kW). The dual rows, each consisting of five cylinders, were offset along the crankshaft by roughly one cylinder radius to produce a more streamlined engine compared to other two-row radials. Each row connected to its own crankpin positioned 180° apart, with robust chrome-nickel steel connecting rods designed to keep the rows closely aligned. The cylinder heads and pistons were composed of cast iron; pistons featured internal and external machining and employed two piston rings. Lubrication was provided by oil forced through the crankshaft to the crankpins, then dispersed via centrifugal action to the cylinders and pistons, all housed within a lightweight alloy crankcase casting.

Both intake and exhaust valves were situated in the cylinder heads. The engine utilized automatic intake valves that opened due to atmospheric pressure and closed with spring assistance; fuel was delivered from a mixing chamber located in the crankcase through rear-positioned inlet tubes, minimizing cooling effects from airflow on the mixture. Exhaust valves were mounted at the front and actuated by a camshaft at the rear of the crankcase via pushrods and rocker arms. A single carburettor supplied fuel-air mixture to the crankcase chambers from below. Certain versions incorporated a single Gibaud magneto operating at 3,000 rpm; British-built models featured dual Bosch magnetos running at lower speeds. In British variants, K.L.G. spark plugs were installed on the cylinder heads at an upward angle on the side to reduce oil fouling risk. Exhaust gases exited through distinct semi-circular exhaust manifolds.

Operational history

In 1914, a British-built Anzani 10 producing 125 hp underwent rigorous testing at Farnborough. The Anzani 10 powered several early aircraft models, mostly in limited quantities. Its principal applications were on the Caudron G.3 and later versions of the G.4, where it often replaced less powerful rotary Gnome engines. Precise production figures are unclear due to various engine substitutions across models. Notably, after September 1917, the American Expeditionary Force acquired 66 Caudron G.4 aircraft equipped with Anzani 10 engines, primarily deploying them as trainers; this resulted in significant exportation of these engines to the United States. Additionally, Clyde Cessna’s first production aircraft, the Model AA, was fitted with Anzani 10 engines, with a total of fourteen units manufactured. Huff-Daland also utilized this engine in multiple designs.