In 1915, Renault started production of 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. The 12Fe was primarily used in bomber aircraft during WW1 and then saw post war service in early airliners and mail planes.[3]
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.[4]
Ignition system has 100% redundancy with two spark plugs per cylinder and four magnetos (two per cylinder bank).[5]
Aircraft powered by the Renault 12Fe set numerous records for distance, endurance and reliability in the early 1920s.[6] [7] The engine proved to be particularly durable. During the first half of 1923 Aéropostale aircraft powered by the 12Fe travelled a collective without experiencing any engine failures. In 1924, a 12Fe powered Latécoère aircraft set a world safety record by traveling without experiencing any engine problems.
The Renault 12Fe is by far the most numerous Renault aero-engine ever produced. 5,300 were built during WW1.[8] Production continued at a slower pace after WW1 with the total number reaching about 7,000 by the mid 1920s.[9]
In the United Kingdom, Renault 12Fe engines were built under license by Renault's British subsidiary and Wolseley Motors.[10]
From 1918, Renault 12Fe engines, fitted to Breguet 14 aircraft, were used to test experimental turbochargers designed by Auguste Rateau.[11] Aircraft fitted with turbocharged 12Fe engines went on to set altitude records in 1919, 1922 and 1923. Ultimately the turbocharged 12Fe engines were rejected for service by the French airforce due to reliability concerns.[11]
The early Rateau turbochargers delivered air to the engine’s carburetor at around two times atmospheric pressure while consuming less than .[12] The following results were obtained in 1918 during tests on a Bréguet 14 fitted with a turbocharged Renault 12Fe engine:[13]
| Test | Naturally aspirated | Turbocharged | % Gain | |
|---|---|---|---|---|
| Speed at | 12% | |||
| Speed at | 16% | |||
| Engine revs at | 1,380 rpm | 1,590 rpm | 15% | |
| Climb rate from | 15% |
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.