Renault 12F
| Industry | Aerospace, automotive |
|---|---|
| Founded | 1899 in France |
| Headquarters | France |
| Products | Aircraft engines, automobiles |
The Renault 12F series comprises liquid-cooled, 50-degree V12 aero engines extensively utilized during World War I and throughout the 1920s.
Originating from the Renault 8G engines, the 12F models maintain identical cylinder bore and stroke dimensions. Manufacturing took place at Renault facilities located in France, Russia, and the United Kingdom.
Initially identified by their nominal horsepower ratings, the series progressed to incorporate aluminum pistons which enhanced output while reducing overall weight. This advancement culminated in the 12Fe variant delivering , officially certified by the STAe and commercially promoted by Renault as 300 CV.
Design and development
Renault debuted water-cooled V8 aircraft powerplants (8G series) in 1914. By the following year, engineers expanded this design into a V12 configuration sharing the same bore, stroke, and bank angle, thus creating the 12F family.
These engines feature a 50-degree V12 layout with a single overhead camshaft per cylinder bank. The crankshaft is supported by four plain bearings and employs master-and-slave connecting rods to align opposing cylinders. Each cylinder has a bore of and stroke of , cast individually and paired with welded liners that allow cooling water to circulate around each pair.
Ignition is fully redundant with two spark plugs per cylinder powered by four magnetos—two assigned to each bank.
Early versions of the 12F included an aluminum six-cylinder radial pneumatic starter mounted at the rear, permitting autonomous engine restarts without ground support. This starter utilized compressed air for up to ten starts but was removed in later iterations.
The first 220 hp (12Fa) model featured cast iron pistons; subsequent adoption of aluminum pistons increased power output while decreasing weight.
By 1917, the 12Fe was officially rated at , later uprated to , becoming the standard engine for the Breguet 14 and accounting for most production units.
The 12F engines were exported to the United States and produced under license in Britain. In Russia, Renault components were assembled by the Russian Renault Society in Petrograd, yielding 98 early models with cast iron pistons between July 1916 and September 1917. In 1921, under Soviet classification, the 12F was designated as M-3, alongside other engines such as M-1 (RBVZ-6) and M-2 (Le Rhone 9J).
Variants
The 12Fe is frequently referred to as the Renault 300 hp model in literature, whereas earlier types are known as Renault 220 hp. After World War I, the 12Fe was marketed using the designation 300 CV (cheval-vapeur), meaning "horsepower" in French.
- 12Fa
- (1915) Delivered at , operating at 1300 rpm. Installed on Breguet 14 aircraft and prototypes of the Henry Farman HF.35, which first flew in December 1915.
- 12Fb
- (1916) Produced between 250 and 265 hp. Powered aircraft such as the Paul Schmitt P.S.7 and Breguet 5.
- 12Fc
- Equipped early Bréguet 14 variants. Subtypes include 12Fcx rated at , running at 1500 rpm, and 12Fcy delivering , at 1600 rpm. In American service, all 12Fc engines were rated uniformly at .
- 12Fe
- Rated at , operating at 1600 rpm. This was the principal production model and became standard on Breguet 14 aircraft from late 1917 onward. Postwar documentation often uses 12Fe and 300 CV/hp interchangeably. Some units were fitted with experimental Rateau turbochargers.
- 12Ff
- Denotes a small batch of engines featuring increased bore (128 mm) and stroke (160 mm), rated at , running at 1600 rpm. These powered select late-production Breguet 14s.
12Fa, 12Fb, and 12Fc
- Breguet 5
- Breguet 14 (early versions and prototype models)
- Henry Farman HF.35
- Henry Farman HF.36
- Nieuport 15
- Paul Schmitt P.S.7
- Curtiss Wanamaker Triplane
- Grigorovich M-24
- Sikorsky Ilya Muromets
12Fe (300 hp)
- Breguet 14 (from late 1917 onward)
- Breguet 16
- Caudron C.91
- Farman F.60 Goliath
- Farman F.70
- Georges Levy G.L.40
- Hanriot HD.18
- Latécoère 14
- Latécoère 17
- Lioré et Olivier LeO 8
- Lioré et Olivier LeO H-13
- Paul Schmitt P.S.10
- Potez XV
- Voisin X
- Airco DH.4
- Royal Aircraft Factory R.E.7
- Short Type 184
12Ff
- Breguet 14 (restricted use during late war period)
External links
- Moteur d'aviation 220 chevaux – Engine manual