Hispano-Suiza 12Y

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 underway, 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.

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.

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 initially known locally as the Avia Vr. 36 and 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.

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]

Licence built variants

Czechoslovakia

Avia Vr. 36^[3]

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

• Amiot 370
• ANF Les Mureaux 110-119 series
• Arsenal VB 10
• Arsenal VG-33
• Avia 156
• Avia B-534
• Bloch MB.177
• Dewoitine D.510
• Dewoitine D.513
• Dewoitine D.520
• EKW C-35
• Fairey Fantôme
• Farman NC.223.3
• Farman NC.223.4
• Ikarus IK-2
• Latécoère 298
• Latécoère 521
• Loire-Nieuport 161
• Morane-Saulnier M.S.406
• Morane-Saulnier M.S.475
• Potez-CAMS 161
• Renard R-36
• Rogozarski IK-3
• Wibault 366

Klimov powered

• Arkhangelsky Ar-2
• Lavochkin-Gorbunov-Goudkov LaGG-1
• Lavochkin-Gorbunov-Goudkov LaGG-3
• Mörkö-Morane
• Petlyakov Pe-2
• Petlyakov Pe-3
• Yakovlev Yak-1
• Yakovlev Yak-2
• Yakovlev Yak-3
• Yakovlev Yak-4
• Yakovlev Yak-7
• Yakovlev Yak-9
• Yermolayev Yer-2

Specifications (12Ycrs)

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

General characteristics

• Type: Twelve-cylinder supercharged liquid-cooled 60° V12 engine
• Bore: 150 mm (5.906 in)
• Stroke: 170 mm (6.693 in)
• Displacement: 36.05 l (2,199.9 in³)
• Length: 1,722 mm (67.8 in)
• Width: 764 mm (30.08 in)
• Height: 935 mm (36.81 in)
• Dry weight:
  
• 12Y 25:475 kg (1,047 lb)
• 12Y 45:515 kg (1,135 lb)

Components

• Valvetrain: One intake and one sodium-filled exhaust valve per cylinder actuated via a single overhead camshaft per bank.
• Supercharger: Gear-driven single-speed centrifugal type supercharger, 10.0:1 gear ratio
• Fuel system: Six Solex 56 S.V.C carburetors
• Fuel type:
  
• Y 25/29:85/100 octane rating gasoline
• Y 45/49:92/100 octane rating gasoline
• Cooling system: Pressurised, Liquid-cooled: 600 litres/min.
• Reduction gear: Spur, 2:3

Performance

• Power output:
  
• 12Y 25: 810 CV (600 kW) (800 hp) at 2,400 rpm for takeoff
• 920 CV (680 kW) (910 hp) at 2,520 rpm at 3,600 m (11,800 ft)
• 12Y 45: 850 CV (630 kW) (840 hp) at 2,400 rpm for takeoff
• 935 CV (688 kW) (922 hp) at 2,520 rpm at 4,200 m (13,800 ft)
• Specific power: 17.08 kW/l (0.38 hp/in³)
• Compression ratio: 12Y 25: 7.2-1 12Y 45: 7-1
• Specific fuel consumption: 328 g/(kW•h) (0.54 lb/(hp•h))
• Oil consumption: 11 g/(kW•h) (0.28 oz/(hp•h))
• Power-to-weight ratio: 1.32 kW/kg (0.8 hp/lb)

See also

• List of aircraft engines

References

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

Notes

Bibliography