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Renault 12Fe
	Renault 12Fe aero-engine. Displayed at the national air and space museum of France.
Type	Water-cooled V12 aero engine
National origin	France
Manufacturer	Renault
First run	Late 1916
Major applications	Breguet 14; Voisin X
Number built	>7,000
Developed from	Renault 12F

The Renault 12Fe, or 300 CV, is a water-cooled V12 aero engine. The 12Fe was the most produced Renault aircraft engine and powered many French aircraft during World War I and the 1920s.

The engines were built in Renault's factories in France and the United Kingdom with additional licensed production by other French and British manufacturers.

By the end of World War I, 12Fe engines powered the bulk of the French bomber force. Post-war the engine type was selected by many of the first airlines and airmail services. During the 1920's 12Fe engines set new standards for endurance and reliability while aircraft fitted with an experimental turbocharged version of the engine claimed a series of high-altitude records.

Design and development

In 1915, Renault started production of 22.08 L (1,347 cu in) water-cooled 50° V12 engines. These engines were progressively improved with the introduction of aluminium pistons allowing for increased power output and reduced weight. In 1917, the 12Fe model was homologated with a nominal rating of 300 hp (later increased to 320 hp). The 12Fe was the main production variant and accounted for the vast majority of engines built in the series.^[1]^[2]

The 12Fe’s crankshaft is carried on four plain bearings. Master-and-slave connecting rods were used allowing corresponding cylinders in each row to be arranged directly opposite each other. Cylinders are built in pairs with water circulated in welded liners using a single impeller centrifugal pump with dual outlets.^[3]

Ignition system has 100% redundancy with two spark plugs per cylinder and four magnetos (two per cylinder bank).^[4]

The engine made use of valve overlap to improve cylinder scavenging. The inlet closed 6 degrees late while the exhaust closed 19 degrees late giving a 13-degree overlap.^[3]

Production

The Renault 12Fe is by far the most numerous Renault aero-engine ever produced.^[1] 5,300 were built during WW1.^[1]^[5] Production continued at a slower pace after WW1 with the total number reaching about 7,000 by the mid 1920s.^[6]

In France, production of the engines took place at Renault’s Paris factories located in Boulogne-Billancourt and Vélizy-Villacoublay. In addition to Renault's own production, some engines were built under license by other French manufacturers including Bellanger and Darracq.^[1]

In the United Kingdom, Renault 12Fe engines were built under license by Renault's British subsidiary and Wolseley Motors.^[7]

The engine was designated as the 12Fe by the Service Technique de l'Aéronautique who treated it as a variant of the 12F series.^[8] Renault marketed the engines as a distinct type which they referred to as the 300 CV (cheval-vapeur) (French: "horsepower”).^[6]

Operational history

The 12Fe was primarily used in bomber aircraft during World War One.^[1] By the end of the war, the 12Fe had become the standard powerplant for the Breguet 14^[9] and had replaced the unreliable Peugeot 8Aa on the Voisin bombers.^[10] After the war the engine continued to be used by military aircraft and saw service in early airliners and mail planes.^[1]

Aircraft powered by the Renault 12Fe set numerous records for distance, endurance and reliability in the early 1920s.^[11]^[12] The engine proved to be particularly durable. During the first half of 1923 Aéropostale aircraft powered by the 12Fe travelled a collective 663,700 km (412,400 mi) without experiencing any engine failures. In 1924, a 12Fe powered Aéropostale aircraft set a world safety record by traveling 150,000 km (93,000 mi) without experiencing any engine problems.^[11]

Rateau turbochargers

From 1918, Renault 12Fe engines, fitted to Breguet 14 aircraft, were used to test experimental turbochargers designed by Auguste Rateau.^[1]^[13] Aircraft fitted with turbocharged 12Fe engines went on to set altitude records in 1919,^[12] 1922 and 1923.^[11] Ultimately the turbocharged 12Fe engines were rejected for service by the French Airforce due to reliability concerns.^[13]

The early Rateau turbochargers delivered air to the engine’s carburetor at around two times atmospheric pressure while consuming less than 30 hp (22 kW).^[14] The following results were obtained in 1918 during tests on a Breguet 14 fitted with a turbocharged Renault 12Fe engine:^[15]

Test	Naturally aspirated	Turbocharged	% Gain
Speed at 6,500 m (21,300 ft)	101 km/h (63 mph)	113 km/h (70 mph)	12%
Speed at 4,200 m (13,800 ft)	167 km/h (104 mph)	194 km/h (121 mph)	16%
Engine revs at 4,200 m (13,800 ft)	1,380 rpm	1,590 rpm	15%
Climb rate from 3,500–4,000 m (11,500–13,100 ft)	2 m/s (6.6 ft/s)	2.3 m/s (7.5 ft/s)	15%

Applications

Engines on display

A preserved Renault 12Fe, fitted with an experimental Rateau turbocharger, is on display at the Musée de l'air et de l'espace. Another Renault 12Fe engine, installed in the nacelle of a Voisin X pusher aircraft, can be seen at the same museum.

One Renault 12Fe engine is on display at the Polish Aviation Museum in Kraków.

Specifications

Data from Angle,^[3] L'Aéronautique^[16] and Renault.^[2] Data is for a naturally aspirated 12Fe engine.

General characteristics

Type: Water–cooled, upright, 50-degree, V-12 piston engine
Bore: 125 mm (4.92 in)
Stroke: 150 mm (5.91 in)
Displacement: 22.08 L (1,347 cu in)
Length: 1.817 m (71.5 in)
Width: 0.8 m (31 in)
Height: 1.136 m (44.7 in)
Dry weight: 360 kg (794 lb) (engine only). 437 kg (963 lb) with propeller, exhaust and radiator.

Components

Valvetrain: SOHC (single overhead camshafts). Two valves per cylinder. When fitted, synchronization gear is attached to end of the right hand camshaft.
Fuel system: Two Zenith duplex carburetors. Heated by jacket water.
Fuel type: Gasoline
Oil system: Wet sump with 2 gear-pumps. 1 pump circulates oil. The other transfers oil from tank to sump. Lubricant: Castor oil.
Cooling system: Water-cooled. One single impeller centrifugal pump. 60 kg (132 lb) of cooling water.
Reduction gear: None. Direct drive.
Rotation: Counterclockwise when looking end on at the propeller hub

Performance

Power output: 327 hp (244 kW) @ 1600 rpm
Compression ratio: 5:1
Fuel consumption: 111 L/h (24 imp gal/h)
Specific fuel consumption: 0.349 kg/kWh (0.573 lb/(hp⋅h))
Oil consumption: 8 L/h (14 imp pt/h)
Power-to-weight ratio: 0.623 kW/kg (0.379 hp/lb)

References

^ ^a ^b ^c ^d ^e ^f ^g Hartmann, Gerard (2005). "Les moteurs d'aviation Renault" [Renault aviation engines] (PDF) (in French). Retrieved 10 December 2023.
^ ^a ^b "Conferences sur les moteurs d'aviation 300 - 450 - 550 hp". Handout Given to Delegates at Renault Factories (Annex A N.E. 21 & N.E. 21A). Renault. December 1921 – via Safran.
^ ^a ^b ^c Angle, Glenn D. (1921). Airplane Engine Encyclopedia. Dayton, Ohio, USA: The Otterbein Press. pp. 417–418.
^ "Moteur d'aviation 300 chevaux" [Engine manual for the 22L 300 hp engine]. Renault – via Safran.
^ Laux, James M (March 1980). "Gnome et Rhône - An Aviation Engine Firm in the First World War: Le Rhône". Aerospace Historian. Vol. 27, no. 1. Air Force Historical Foundation. p. 20.
^ ^a ^b Les Moteurs D'Aviation Renault. Drager – via Safran.
^ Lumsden, Alec (2002). British Piston Engines and their Aircraft. Airlife Publishing. p. 181. ISBN 1853102946.
^ Type 14 A2. Model 1921 (PDF). Notice Technique de l'Avion Breguet (Report). Ministere de la guerre. 24 April 1922.
^ Toelle, Alan D (2003). "Motors and Cowlings". Breguet 14. Albatros Productions Limited (Windsock Datafile Special). pp. 52–53. ISBN 1902207610.
^ Treadwell, Terry C (2011). British and Allied Aircraft Manufacturers of the First World War. Amberley. pp. 725–726. ISBN 978-1-4456-0101-4.
^ ^a ^b ^c Records et performances des moteurs d'aviation Renault. Paris France: Drager – via Safran.
^ ^a ^b Hatry, Gilbert (12 June 1981). "Renault et l'aviation". Bulletin de la Section d'Histoire des Usines Renault (in French) (22) – via Safran.
^ ^a ^b Bruce, J.M; Noel, Jean (1967). The Breguet 14. 157. United Kingdom: Profile Publications. ASIN B0007JXD5I.
^ "Lautaret engine tests". The Bulletin of the Experimental Department. Airplane Engineering Division U.S.A. 1 (2): 132. July 1918.
^ "Supercharging Progress in the United States". The Bulletin of the Experimental Department. Airplane Engineering Division U.S.A. 2 (4): 7. January 1919.
^ "Les Moteurs Renault" [Renault Engines]. L'Aéronautique (in French). France. 1 December 1922. p. 42.