Renault 12F

The Renault 12F is a family of liquid-cooled 22 L 50 deg V12 aircraft engines that saw widespread use during WW1 and the 1920s.

Design and development
Engines in the series are V12s with a 50 degree angle between two rows of cylinders each of which has a single overhead camshafts. The crankshaft is carried on four plain bearings with master-and-slave connecting rods allowing corresponding cylinders in each row to be arranged directly opposite each other. Cylinders have a bore of 125 mm, a stroke of 150 mm and are built in pairs with water circulated in welded liners.

Engines in the series have ignition systems with 100% redundancy. Two spark plugs per cylinder and four magnetos (two per cylinder bank).

The early 12F engines were often supplied with an aluminium six-cylinder radial pneumatic starter motor which was mounted on the back of the engine. The pneumatic motor allowed the engine to be restarted mid-flight or on the ground without assistance from ground crew. The starter motor was fed from a pressurised vessel with enough air for ten starts. The device was not included in later models.

In 1916 the 220 hp (12Fa) model used cast iron pistons. The engines were progressively improved with the introduction of aluminum 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 became the standard powerplant for the Breguet 14 and accounted for the vast majority of engines built from the series.

12F series engines were exported to the United States and produced in the United Kingdom.

In Russia, Renault 12F engines were assembled from imported parts by the Russian Renault Society in Petrograd. A total of 98 engines were assembled from July 1916 to September 1917. All the engines assembled were early 12F models with cast iron pistons.

Variants
Publications often refer to the 12Fe as the Renault 300 hp with earlier engines in the series referred to as the Renault 220 hp. Post WW1 the 12Fe engine was marketed as the 300 CV / hp (cheval-vapeur / horsepower). There was also a 18 L 220 hp model (today known as the 12Eb) which existed at the same time (c.1916) as the 22 L 220 hp model.


 * 12Fa
 * (1916) Rating of 220 hp at 1300 rpm. Used on the Breguet 14s and Henry Farman HF.35 prototypes.


 * 12Fb
 * (1916) Rating of 250 or 265 hp. Equipped the Paul Schmitt P.S.7.


 * 12Fc
 * Used on early model Bréguet 14s. 12Fcx (250 hp at 1500 rpm) and 12Fcy (280 hp at 1600 rpm) sub-variants. In US service 12Fc engines were all rated at 300 hp.


 * 12Fe


 * Rated for 300 hp at 1600 rpm. Main production variant in the series and the standard power-plant in the Breguet 14 from early in 1918 onwards. The names 12Fe and 300 CV / hp (cheval-vapeur / horsepower) are used interchangeably in post war technical documentation. Some of these engines were fitted with early experimental Rateau turbochargers.


 * 12Ff
 * Sometimes used to describe a small number of engines produced with increased bore (128 mm) and stroke (160 mm). Rated for 350 hp at 1,600 rpm. These engines were fitted to a few late production Breguet 14s.

Applications

 * Breguet 5
 * Breguet 14
 * Breguet 16
 * Caudron C.91
 * Farman F.60 Goliath
 * Farman F.70
 * Georges Levy G.L.40
 * Hanriot HD.18
 * Henry Farman HF.35
 * Latécoère 14
 * Latécoère 17
 * Lioré et Olivier LeO 8
 * Lioré et Olivier LeO H-13
 * Nieuport 15
 * Paul Schmitt P.S.7
 * Paul Schmitt P.S.10
 * Potez XV
 * Voisin X
 * Airco DH.4
 * Royal Aircraft Factory R.E.7
 * Short Type 184
 * Curtiss Wanamaker Triplane
 * Grigorovich M-24
 * Sikorsky Ilya Muromets