Hispano-Suiza 12Y

12Y
Type V-12 piston aero engine
National origin France
Manufacturer Hispano-Suiza
First run 1932



The Hispano-Suiza 12Y was an aircraft engine produced by Hispano-Suiza for the French Air Force in the pre-WWII period. The 12Y became the primary 1,000 hp (750 kW) class engine and was used in a number of famous aircraft, including the Morane-Saulnier M.S.406 and Dewoitine D.520. Its design was based on the earlier and somewhat smaller, 12X. A further development was under way, the 12Z, but ended due to the German occupation of France.

The 12Y was also produced under Hispano-Suiza licence in the Soviet Union as the Klimov M-100. This design later spawned the highly successful Klimov VK-105 series that powered the Yakovlev and Lavochkin fighters as well as the Petlyakov Pe-2 bomber. Licensed production of the early models was also undertaken in Czechoslovakia as the Avia HS 12Ydrs, and in Switzerland as the HS-77.

Design and development

Early development

The 12Y was a fairly traditional in construction, a 36-litre water-cooled V-12 with the two cast aluminium cylinder banks set at 60 degrees to each other. The cylinder heads were not removable, instead the entire block could be quickly removed from the engine. This made it somewhat famous for being leak-proof, a design feature that was considered by other designers and almost became a part of the Rolls-Royce Merlin. The major design change from the earlier 12X was to use a master-articulated connecting rod system, instead of the fork-and-blade type. A single overhead camshaft (SOHC) drove the valves, which were filled with liquid sodium for cooling. Only a single intake and exhaust valve were used, unlike most designs of the era which had moved to three or four valves per cylinder. A single-stage, single-speed supercharger was standard, although the art of designing a useful intake was not as well developed as in other countries, and high altitude performance was always lacking.

The first 12Y test articles were constructed in 1932, and almost immediately the entire French aviation industry started designing around it. At the time the engine developed only 760 hp (570 kW), but it was clear it had potential to the 1,000 hp (750 kW) class. An early modification led to the Hispano-Suiza 12Ycrs which used a hollow propeller shaft to allow a 20 mm cannon to fire through the propeller spinner (a combination known as a moteur-canon). All later designs shared this feature. The 12Ydrs was the next major series, with a basic rating of 836 hp (623 kW) at sea level with a compression ratio of 5.8:1.

The Armée de l'Air changed their nomenclature, so the next version was the Hispano-Suiza 12Y-21, which increased the compression ratio to 7:1, when running on 100 octane gasoline. This boosted power to 867 hp (647  kW). In 1936 the connecting rod design was changed slightly to create the 12Y-31, but the lower 5.8:1 compression ratio was retained and the power was increased only slightly over the drs model to 850 hp (630 kW). Nevertheless this became one of the most used engine designs of the pre-war era, used in almost all French fighter designs and prototypes.

12 Ybrs showing valve gear

Late variants

A real effort to improve the performance of the engine in 1938 resulted in the Hispano-Suiza 12Y-45, which used the S-39-H3 supercharger co-designed by André Planiol and Polish engineer Joseph Szydlowski. The Szydlowski-Planiol device was larger, but much more efficient than the indifferent Hispano-Suiza models. When used with 100 octane fuel, the supercharger boosted to the -21's 7:1, increasing power to 900 hp (670 kW). Combined with the fully adjustable Ratier propeller, this allowed the D.520 to perform as well as contemporary designs from Germany and England.

Another improvement in supercharging led to the Hispano-Suiza 12Y-49, whose performance improved from 850 hp (630 kW) at sea level to 920 hp (690 kW) at just over 10,000 ft (3,000 m). This improvement in power with altitude was a common feature of most engines of the era, the result of the supercharger "robbing" power at low altitudes (coupled with the fact that full boost couldn't be used unless the ambient air pressure was low enough; attempting to use full boost at sea level would push too much air into the cylinders, causing detonation. Thus you had the supercharger being driven by the engine, but adding little to the power).

The final major version was the 1,085 hp (809 kW) Hispano-Suiza 12Y-51, which had just started into production at the time of the Armistice with Germany. The -51 was the first version that came close to the performance limits of the engine, although the single-stage supercharging meant that it was unable to compete with designs from England and Germany above 15,000 ft (5,000 m).

Foreign derivatives

In the early 1930s the Czechoslovakian Republic gained rights to build a license version of the HS-12Y. This was produced by Avia (Škoda) at Prag - Čakovice. The engine was intended to become the standard powerplant of all Czech military aircraft. Both the HS-12Ycrs and HS-12Ydrs were built in quantity and were more commonly known by these names rather than any Czech designation. Aircraft powered by these engines included the Avia B-34, Avia B-534, Avia B-71, Avia B-35 and Avia B-135.

Switzerland license built and assembled several different versions of the basic 12Ycrs for use in several aircraft: the reconnaissance biplane the EKW C-35, the multipurpose EKW C-36, the Swiss assembled D-3800 copy of the French M.S. 406 fighter and Swiss built versions of the French M.S.412 fighter called the D.3801. Saurer developed the engine further after the Fall of France into the YS-2 and YS-3 engines. These were used in more powerful follow-on versions of the same basic French fighter design, the M.S.450 called the D.3802 and then the final version called the D.3803.

In the mid-1930s, Russian engineer Vladimir Klimov was sent to France to obtain a license for local production of the 12Y. A series of design changes were added to cope with cold weather operation, and the engine entered production in 1935 as the Klimov M-100 with about 750 hp (560 kW).[1] However a series of continual upgrades increased the allowable RPM from the 12Y's fairly low 2,400 to 2,700, thereby increasing power to 1,100 hp (820 kW). The resulting design, the Klimov M-105 (VK-105) became one of the major Soviet engine designs during the war, powering all Yakovlev fighters.

Variants

Tabulated data from Lage 2004[2]

Type 73 Hispano 12Y engines. V-12, bore=150 mm, stroke=170 mm, capacity=36.0 litres. Type 77 with 20 mm Hispano-Suiza HS.404 cannon between cylinder banks, firing through propeller shaft.
Model Year Compression Power (hp) @ r.p.m. T-O power (hp) Output reduction Supercharger optimum altitude (m) Weight (kg) Cannon (y/n) Comments
12Ybr 650 hp 1932 6.4 785 2,200 785 1.5 0 415 n Rated power (650 hp) less than nominal 785 hp
12Ybrs 1934 5.8 860 2,400 835 1.0625 4,000 470 y
12Ycrs 1934 5.8 860 2,400 835 0.67:1 4,000 470 y
12Ygrs 650 hp 1932 5.8 850 2,400 800 1.5 4,000 430 n Rated power (650 hp) less than nominal 850 hp
12Ydr 1934 6.4 800 2,200 800 1.5 0 440 n As 12Ybr, variable-pitch propeller, left turning. For this and all later entries in both tables, Rated power = Nominal power = Power
12Ydrs 1934 5.8 860 2,400 835 1.5 4,000 470 n As 12Ybrs, variable-pitch propeller, left turning
12Ydrs1 1934 5.8 880 2,400 890 1.5 2,400 470 nVariable-pitch propeller, left turning
12Ydrs2 1934 5.8 930 2,400 992 1.5 900 470 n Variable-pitch propeller, left turning
12Yfrs 1934 5.8 860 2,400 835 1.5 4,000 470 nAs 12Ydrs, right turning
12Yfrs1 1934 5.8 880 2,400 890 1.5 2,400 470 n As 12Ydrs1, right turning
12Yfrs2 1934 5.8 930 2,400 992 1.5 900 470 n As 12Ydrs, right turning
12Y-21 1935 7.0 910 2,400 880 1.5 3,600 470 n
12Y-25 1935 5.8 860 2,400 943 1.5 3,600 n As 12Ydrs, variable ignition timing
12Y-26 1935 5.8 900 2,400 950 1.8 850 483 opposite rotation to -27
12Y-27 1935 5.8 900 2,400 950 1.8 850 483 opposite rotation to -26
12Y-28 7.2 920 2,400 910 0.67:1 3,600 475 y LH rotation
12Y-29 7.2 920 2,400 910 0.67:1 3,600 475 yIdentical to -28 but RH rotation
12Y-30 1936 5.8 860 2,400 830 0.67:1 3,250 468 y Redesigned connecting rods,LH rotation
12Y-31 1936 5.8 860 2,400 830 0.67:1 3,250 468 yIdentical to -30 but RH rotation
12Y-32 1936 5.8 960 2,400 955 0.67:1 2,300 468 y Redesigned connecting rods,LH rotation
12Y-33 1936 5.8 960 2,400 955 0.67:1 2,300 468 y Identical to -32 but RH rotation
12Y-36 1936 7.0 960 2,400 1,050 0.55:1 1,250 483 y LH rotation
12Y-37 1936 7.0 960 2,400 1,050 0.55:1 1,250 483 y Identical to -36 but RH rotation
12Y-38 1936 7.0 1000 2,400 1.5 3,400 n LH rotation
12Y-39 1936 7.0 1000 2,400 1.5 3,400 n Identical to -38 but RH rotation
12Y-41 1936 7.0 920 2,400 0.67:1 3,600 483 y
12Y-45 7.0 920 2,400 935 0.67:1 4,200 y Szydlowsky-Planiol (SP) supercharger
12Y-47 1936 5.8 860 2,400 830 0.67:1 3,250 468 y
12Y 49 7.0 910 2,400 910 0.67:1 5,250 y (SP) supercharger, variable ignition timing
12Y-50 1939 7.0 1,000 2,500 1,100 0.67:1 3,260 492 y (SP) supercharger LH rotation
12Y-51 1939 7.0 1,000 2,500 1,100 0.67:1 3,260 492 y Identical to -50 but RH rotation
Model Year Compression Power (hp) @ r.p.m. T-O power (hp) Output reduction Supercharger optimum altitude (m) Weight (kg) Cannon (y/n) Comments

Licence built variants

Czechoslovakia
Avia HS 12Y
USSR
Klimov M-100[3][4]
12 Ydrs Also known as VK-100
Klimov developments[4]
VK-103
VK-103A 1,100 hp (820 kW) at 2,000 m (6,600 ft)
VK-104
VK-105P 1,100 hp (820 kW) at take-off
VK-106 1,350 hp (1,007 kW) at take-off
Switzerland
Hispano-Suiza HS-77
12 Ycrs

Applications

Klimov powered

Specifications (12Ycrs)

Data from Le Dewoitine D.520[5][6]

General characteristics

Components

Performance

See also

References

Wikimedia Commons has media related to Hispano-Suiza 12Y.

Notes

  1. ↑ Kotelnikov 2005, p. 136.
  2. ↑ Lage, 2004, p.486-7
  3. ↑ Gunston 1989
  4. 1 2 Lage, 2004, pp.258-260
  5. ↑ Danel and Cuny 1966, pp. 245-248.
  6. ↑ Hispano-Suiza 12Y-47 Retrieved: 1 October 2010.

Bibliography

  • Danel, Raymond and Jean Cuny. Docavia n°4: le Dewoitine D.520 (in French). Paris: Editions Larivière, 1966.
  • Kotelnikov, Vladimir. Russian Piston Aero Engines. Marlborough, Wiltshire. The Crowood Press Ltd. 2005. ISBN 1-86126-702-9.
  • Hispano-Suiza 12Y-47 Retrieved: 1 October 2010.
  • Wilkinson, Paul H.. Aircraft Engines of the World 1945. Paul H. Wilkinson. New York. 1945
  • Gunston, Bill. World Encyclopedia of Aero engines fully revised second edition. Patrick Stephens Limited. Wellingborough. 1989. ISBN 1-85260-163-9
  • Lage, Manual (2004). Hispano Suiza in Aeronautics. Warrendale, USA: SAE International. pp. 486–7. ISBN 0-7680-0997-9. 
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