Hispano-Suiza 12N

The Hispano-Suiza 12N was one of two new V-12 engine designs first run in 1928 and was manufactured by Hispano-Suiza's French subsidiary for the Armee d'l'Air. It produced about 485 kW (650 hp), was the first to use gas nitride hardening and introduced wet cylinder liners into Hispano-Suiza's aircraft engine range. It powered the first non-stop flight from Europe to the United States.

Type V-12
National origin France
Manufacturer Société Francaise Hispano-Suiza
Designed by Marc Birkigt
First run 1928
Unit cost 250,000 FF (1931)
Variants Hispano-Suiza 18R

Design and development

Up to 1927, Hispano-Suiza's many engine types, of various layouts and cylinder numbers, were all recognisable developments of the World War I V-8 Hispano-Suiza 8. 1927-8 saw the introduction of four completely new engines, two V-12s and two with six cylinders inline. The Hispano-Suiza 12N, known by the manufacturers as the Type 61, was the larger of the V-12s, with a displacement of 36 L (2,200 cu in), the other being the 27 L (1,600 cu in) 12M. Apart from capacity and power, these two engines had much in common. The 12M first ran in 1927 and the 12N a year later.[1]

Both 12M and 12N were 60° V engines with carburettors, inlets and exhausts on the outer faces. There were three carburettors per bank, each charging a pair of cylinders. Much of the new technology was in the cylinder design: these types introduced wet liners, an Hispano automobile engine innovation which brought the cooling water into direct contact with the steel cylinder barrel rather than by screwing it into an aluminium water jacket. This improved cooling, simplified assembly and allowed larger cylinder bores without increasing their separation. The cylinder barrels were open at top and bottom and threaded for screwing into the block only near the top, with valve seats ground into the aluminium cylinder head. The lower end of the barrel extended into the crankcase, simplifying both manufacture and assembly. Block and crankcase were bolted together.[2]

The 12M and 12N engines were the first to use the gas nitriding surface hardening process on the cylinder walls, which reduced both wear and oil consumption. They also used a novel, complicated but effective method of main bearing cooling, enhancing the local lubricant flow without requiring high overall oil pump speeds.[1]

Both types were designed so that Epicyclic gearing could be added or removed quickly; some earlier Hispano-Suiza engines offered gearing but as a permanent fixture on a specific sub-type. The gears added 45 kg (99 lb) to the weight. In 1935 the 12Ner variant was fitted with an in-flight- electrically operated variable pitch propeller.[1]

The 12N series was developed into the 12Y (Type 73) supercharged engine, first run in 1932.[3]

Operational history

A Hispano-Suiza 12Nb powered the Breguet XIX Point d'Interrogation on the first non-stop flight from Paris to New York in September 1930. This was the first east to west flight between Europe and the United States, rather than to the North American continent.[1]

In the early 1930s, 12N engines powered the flying boats operating the French Atlantic and African routes.[1]

The Swiss government, in the form of the KTA (Kriegstechninischen Abteilung or War Technical Department) purchased construction licences for the 12Nb and in 1932 eighty units were built at the Saurer lorry factory.[1]


Data from Hispano Suiza in Aeronautics.[1]

Compression ratio 6.2, maximum power 560 kW (750 hp) at 2,100 rpm.
Compression ratio 6.2, maximum power 550 kW (740 hp) at 2,100 rpm. Gearing ratio of 2:1 or 1.61:1.
Compression ratio 7, nominal power 670 kW (900 hp) at 2,200 rpm. For Schneider Cup 1928.
Compression ratio 10, nominal power 745 kW (999 hp) at 2,400 rpm. For Schneider Cup 1931. Farman compressor.
Compression ratio 6.2, nominal power 533 kW (715 hp) at 2,000 rpm. For Ford 14A Trimotor.
Electrically controlled pitch propeller, anti-clockwise turning (1935).
As 12Ndr, modified with articulated connecting rods.
As Ndr, clockwise turning.
As Ner, clockwise turning.


Specifications (12Nbr/650)

Data from Hispano-Suiza in Aeronautics[1]

General characteristics



See also

Comparable engines

Related lists


  1. Lage, Manual (2004). Hispano Suiza in Aeronautics. Warrendale, USA: SAE International. pp. 135–143, 484. ISBN 0-7680-0997-9.
  2. Lage 2004, p. 147
  3. Lage 2004, pp. 177–81
  4. Liron, J.L. (1990). Les avions Bernard. Paris: Éditions Larivère. pp. 224–5.
  5. Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. New York: Portland House. p. 192. ISBN 0-517-69186-8.
  6. "Breguet Bre.330". Retrieved 19 October 2012.
  7. Taylor 1989, p. 227
  8. Taylor 1989, p. 269
  9. Liron, J.L. (1984). Les avions Farman. Paris: Éditions Larivère. pp. 228–231.
  10. Cuny, Jean (1992). Latécoère Les avions et hydravions. Paris: Editions Larivière. pp. 84, 87. ISBN 2 84890067 9.
  11. Cuny 1992, p. 199
  12. Cuny 1992, pp. 132, 137
  13. Cuny 1992, p. 124
  14. Cuny 1992, p. 195
  15. Cuny 1992, p. 247
  16. Cuny 1992, p. 153
  17. Taylor 1989, p. 573
  18. Taylor 1989, p. 575
  19. Taylor 1989, p. 580
  20. James, Derek (1991). Westland Aircraft since 1915. London: Putnam Publishing. p. 153. ISBN 0 85177 847 X.
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