Renault 12F Explained

The Renault 12F is a family of liquid-cooled 50 deg V12 aircraft engines that saw widespread use during WW1 and the 1920s.[1]

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 camshaft. 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, a stroke of and are built in pairs with water circulated in welded liners.[2] [3]

Engines in the series have ignition systems with 100% redundancy. Two spark plugs per cylinder and four magnetos (two per cylinder bank).[4] [5]

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.[4] [6] 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.[4] The device was not included in later models.[5]

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 (later increased to). The 12Fe became the standard powerplant for the Breguet 14[7] 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.[8]

In Russia, Renault 12F engines were assembled from imported parts by the Russian Renault Society in Petrograd.[9] [10] 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 (cheval-vapeur) (French: "horsepower”).[11]

12Fa
  • (1916) Rating of 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 and the Breguet 5.[12]
    12Fc
  • Used on early model Bréguet 14s. 12Fcx (at 1500 rpm) and 12Fcy (at 1600 rpm) sub-variants. In US service 12Fc engines were all rated at .
    12Fe

    See main article: Renault 12Fe.

    Rated for 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.[13] Some of these engines were fitted with early experimental Rateau turbochargers.[14]

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

    Applications

    External links

    Notes and References

    1. Web site: Hartmann. Gerard . 2005 . Les moteurs d’aviation Renault. Renault aviation engines. FR . 10 December 2023.
    2. Conferences sur les moteurs d'aviation 300 - 450 - 550 hp . Handout given to delegates at Renault factories . Renault . December 1921 . Annex A N.E. 21 & N.E. 21A . Safran.
    3. Book: Angle . Glenn D. . Airplane Engine Encyclopedia . 1921 . The Otterbein Press . Dayton, Ohio, USA . 417-418.
    4. Moteur d'aviation 220 chevaux . Engine manual for 22L 220 hp model . Renault.
    5. Moteur d'aviation 300 chevaux . Engine manual for the 22L 300 hp engine . Renault . Safran.
    6. Book: Les Moteurs D'Aviation Renault . Drager . Safran.
    7. Book: Toelle, Alan D . Breguet 14 . 2003 . Albatros Productions Limited (Windsock Datafile Special) . 1902207610 . 52-53 . Motors and Cowlings.
    8. Book: Lumsden, Alec . British Piston Engines and their Aircraft . 2002 . Airlife Publishing . 1853102946 . 181 . en.
    9. Web site: Klimov United Engine Corporation. Jsc klimov . 31 January 2013 . Kupichic.ru.
    10. Book: Kotelnikov, Vladimir . Отечественные авиационные поршневые моторы. 1910–2009 . 2010 . Litres . 978-5-91244-017-5 . 54-63 . Russian . Domestic aircraft piston engines. 1910–2009.
    11. Book: Hatry, Gilbert . Renault et l'aviation . 1984 . Editions JCM . 32-41 . French . Renault and aviation . Safran.
    12. Book: Treadwell, Terry . British and Allied Aircraft Manufacturers of the First World War . 2011 . Amberley . 9781445620091 . United Kingdom . Société des Avions Louis Breguet.
    13. 24 April 1922 . Type 14 A2. Model 1921. . Notice technique de l'avion Breguet. Ministere de la guerre . N.C.C.9.
    14. Book: Bruce, J.M . The Breguet 14 . Noel . Jean . 1967 . Profile Publications . 157 . United Kingdom . B0007JXD5I.

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