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Hispano-Suiza 8A
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Wolsely W.4A Viper
Wright-Hisso A
Wright-Hisso H
Mitsubishi "Hi" Shiki

 

Hisso-8
Hispano-Suiza 8

 

The Hispano-Suiza 8 was a water-cooled V8 SOHC aero engine introduced by Hispano-Suiza in 1914 and was the most commonly used engine in the aircraft of the Entente Powers during the First World War. The original Hispano-Suiza 8A was rated at 140 hp (102 kW) and the later Hispano-Suiza 8F reached 300 hp (220 kW).

HS-8 engines and variants produced by Hispano-Suiza and other companies under licence were built in twenty-one factories in Spain, France, Britain, Italy, and the U.S. Derivatives of the engine were also used abroad to power numerous aircraft types and the engine can be considered as the ancestor of another successful engine by the same designer, the Hispano-Suiza HS-12Y (and Soviet Klimov V12 derivative aero-engines) which served in World War II.

When World War I began, the production lines of the Barcelona based Hispano-Suiza automobile and engine company were switched to the production of war materiel. Chief engineer Marc Birkigt led work on an aircraft engine based on his successful V8 automobile engine. The resulting engine, called the Hispano-Suiza 8A (or HS-8A), made its first appearance in February 1915.

The first 8A kept the standard configuration of Birkigt's existing design: eight cylinders in 90° Vee configuration, a displacement of 11.76 litres (717.8 cu in) and a power output of 140 hp at 1,900 rpm. In spite of the similarities with the original design, the engine had been substantially refined. The crankcase was machined from a solid piece of steel. The cylinders were cast aluminium with steel liners. The SOHC cylinder heads were also made of aluminium, using a rotary driveshaft (tower gear) coming up from the crankcase along the rear end of each cylinder bank, with the final drive for each cylinder bank's camshaft accommodated within a semicircular bulge at the rear end of each valve cover. Aluminium parts were coated in vitreous enamel to reduce leakage. All parts subject to wear, and those critical for engine ignition were duplicated: spark plugs for dual ignition reliability, valve springs, magnetos, etc.

Although engine reliability was a great concern in these opening stages of aviation, the HS-8A also provided a good power-to-weight ratio and development potential. The engine and its accessories weighed 185 kg (408 lb), making it 40% heavier than a rotary engine of equivalent power. The design also promised far more development potential than rotary engines which, in spite of being the most common type then in use for aircraft, were getting close to the limits of their potential. Rotary engines of increased power generally had increased weight, which in turn increased the already serious gyroscopic torque generated by the engine's rotation. A further increase in torque was considered unacceptable, and the power-to-weight ratio of the new rotary engines under development did not appeal to aircraft designers.

The new engine was presented to the French Ministère de la Guerre (Ministry of War) in February 1915, and tested for 15 hours at full power. This was standard procedure for a new engine design to be admitted in military service. However, because of lobbying by French engine manufacturers, the HS-8A was ordered to undergo a bench test that no French-made engine had yet achieved successfully: a 50-hour run at full speed. The HS-8A was therefore sent back to Chalais-Meudon on July 21, 1915 and tested for 50 hours, succeeding against all expectations.

French officials ordered production of the HS-8A to be started as soon as possible and issued a requirement for a new single-seat high-performance fighter aircraft using the new engine. The SPAD VII was the result of this requirement and would allow the Allies to regain air superiority over the Germans.

Guynemer informed Bechereau in December 1916 that "the Halberstadt [while] not faster, climbs better, consequently it has the overall advantage". In the quest for more power, Marc Birkigt increased the compression ratio of the 8A engine from 4.7 to 5.3, which in turn raised its revolutions from 1500 to 1800 per minute. This resulted in a power output of 180hp, enabling a significant improvement in the SPAD VII's performance to be achieved. Apart from the extra power, the new Hispano-Suiza 8Ab proved extremely reliable

Approximately 49,800 were built.

 

The Wolseley Viper is a British-built, high-compression derivative of the Hispano Suiza HS-8 liquid-cooled V-8 engine, built under licence by Wolseley Motors during World War I and first run in 1918.

It powered later models of the S.E.5a, SPAD VII and other British or British-built aircraft designed for the Hispano-Suiza.

 

Wols-Viper

Wolsley Viper

 

Variants:

8A (HS-8A)
The first model of the Hispano-Suiza 8 produced in any quantity.

 

8Aa (HS-8Aa)
The HS-8Aa, which entered production in July 1915, was the production variant of the basic HS-8A type, with increased power output: 150 hp (110 kW) at 2,000 rpm. Early HS-8A engines were plagued with various problems which required further work. The 150 hp HS-8Aa was the standard powerplant for early-production SPAD VIIs. The demand for the Hispano-Suiza engine was such that other manufacturers began producing it under licence, in France, Great Britain (Wolseley Adder), Italy (Nagliati in Florence and Itala/SCAT in Turin) and Russia. Total production of the HS-8Aa amounted to some 6,000 engines. To avoid the problems experienced by the 8A, Wolseley reduced the compression ratio to 4.7 in the Adder but opted for 5.3 in other variations such as the Viper.

 

8Ab (HS-8Ab)
The HS-8Ab was yet another evolution of the HS-8A. By increasing the compression ratio from 4.7 to 5.3, Birkigt was able to increase the power output to 180 hp (132 kW) at 2,100 rpm. The HS-8Ab began replacing the 8Aa on SPAD VIIs in early 1917.

 

8Ac (HS-8Ac)

 

8B (HS-8B)
The HS-8Ab had been plagued by engine failures due to the high compression ratio: piston heads were sometimes pierced and engines seized. In another ploy to increase the power output of the engine, Birkigt chose to increase engine speed.

 

8Ba (HS-8Ba)
The first, the HS-8Ba, kept the 4.7 compression ratio of the HS-8Aa but delivered 200 hp (147 kW) at 2,300 rpm.

 

8Ba (HS-8Bb)
The second version, the HS-8Bb, had a compression ratio of 5.3. A reduction gear (3:4 ratio) was fitted to compensate for the increased engine speed. However the reduction gear system was fragile, and often broke down, sometimes with spectacular results ending up with the entire propeller, driveshaft and driven gear parting company from the airframe. Progressive refinement of the engine brought the available power to 235 hp by the end of 1917.
The HS-8B was used to power the earliest versions of the S.E.5a, all examples of the SPAD S.XII and SPAD S.XIII, front-line versions of the Sopwith Dolphin and several other Allied aircraft types, with its gear reduction easily identifiable in vintage World War I photos, from its use of a clockwise (viewed from in front, otherwise known as a left hand tractor) rotation propeller.

 

8Ba (HS-8Be)

 

8Ca (HS-8Ca)
The HS-8Ca, a gear-reduction equipped powerplant with a resultant clockwise rotation propeller like the 8B, produced 220 hp at 2,100 rpm. It had a manually loaded 37 mm Puteaux SA 18 cannon mounted between the cylinder banks (a so-called moteur-canon) that could fire a single shot at a time through the hollow drive shaft without propeller interference. The engine was used on the SPAD S.XII.

 

8F (HS-8F)
The HS-8F was basically an enlarged version of the HS-8B, and was intended for use in bombers. Displacement rose to 18.5 liters (1,127.3 in3), with a power of 300 hp (220 kW) at 2,100 rpm (eq. 750 lb·ft torque). Despite the increased weight of 256 kg (564 lb), the HS-8F was installed in fighters such as the Nieuport-Delage NiD 29 and Martinsyde Buzzard, and it would have powered the never-produced Mk.II version of the Sopwith Dolphin. Engine speed being lower than that of the HS-8B, the reduction gear was deleted, thereby increasing engine reliability.

 

8Fa (HS-8Fa)

8Fb (HS-8Fb)

8Fd (HS-8Fd)

Wolseley W.4B Adder I

Wolseley W.4B Adder II

Wolseley W.4B Adder III

Wolseley W.4A Python I

Wolseley W.4A Python II

 

Wolseley W.4A Viper
Was an improved 8A. Wolseley's engineers removed problems with the crankshaft and increased the compression ratio to give more power. It did not need the reduction gearing of the H-S8.

 

Wolseley W.4A Viper II
The Viper II could deliver 210 hp at 2,000 rpm.

 

Wright-Hisso A

 

Wright-Hisso E
The American Wright-Martin aviation firm licence-produced the original 150 hp HS-8Aa engine as the Wright-Hispano E, for use in World War I combat aircraft to be built in the United States – it found its way into the JN-4H version of the Curtiss Jenny, replacing the Curtiss OX-5 liquid-cooled V8 engine of only 90 hp output.


Wright-Hisso H

Wright-Hisso I

Wright-Hisso T

 

Applications:
Austin-Ball A.F.B.1
Avia BH-21
Avia BH-22
Bartel BM-5
Bernard SIMB AB 10
Blanchard Brd.1
Caudron C.59
Caudron R.11
Curtiss JN-4H Jenny
FBA Type H
Fokker D.IX
Fokker D.X
Fokker D.XII
Fokker S.III
Gourdou-Leseurre GL.21
Hanriot HD.5
Hanriot HD.15
Hanriot HD.20
Letov Š-7
Letov Š-13
Letov Š-14
Martinsyde F.4 Buzzard
Nieuport 29 (8Fb)
S.E.5 and S.E.5a (8a and Viper),
Sopwith Dolphin (8B)
Sopwith Cuckoo
SPAD S.VII (8a)
SPAD S.XI (8Be)
SPAD S.XII (8Cb), with 37 mm calibre moteur-canon mount through the hollow propshaft
SPAD S.XIII (8Be)
Standard J-1 training biplanes, especially on restored, airworthy examples
Waco DSO (8a)
Wibault 1

Wright-Hispano E
Boeing NB-2
AT-3
Consolidated PT-1
Cox-Klemin TW-2
Dayton-Wright TW-3
Huff-Daland TW-5
Curtiss AT-4
Vought VE-7
Waco DSO

Mitsubishi "Hi" shiki
200 HP (8B)
Yokosuka Ro-go Ko-gata
Hansa-Brandenburg W.29 (Japanese version)

300 HP (8F)
Mitsubishi 1MF
Mitsubishi 2MR

 

Wolsely W.4
Airco DH.9
Avro 552
Bristol M.R.1
Bristol Tourer
Cierva C.8
Martinsyde F.6
Royal Aircraft Factory S.E.5a
Sopwith Antelope
Sopwith Cuckoo


Specifications:

Hispano-Suiza 8a
Type: 8-cylinder liquid-cooled Vee piston engine
Bore: 120 mm (4.724 in)
Stroke: 130 mm (5.118 in)
Displacement: 11.76 L (717.8 in3)
Dry weight: 445 lb (202 kg)
Fuel system: 1 Claudel or Zenith Carburetor
Cooling system: liquid
Fuel consumption: 0.51 lb/(hp·h)
Oil consumption: 0.03 lb/(hp·h)
Power output: 140 hp at 1900 rpm
Length: 1.19 m
Width: 0.81 m
Height: 0.77 m
Compression ratio: 4.7

8Aa
Bore: 120 mm
Stroke: 130 mm
Displacement: 11.76 lt
Compression ratio: 4.7
Length: 1.25 m
Width: 0.83 m
Height: 0.81 m
Weight: 215 kg
Power output: 150 hp at 2000 rpm

8Ab
Bore: 120 mm
Stroke: 130 mm
Displacement: 11.76 lt
Compression ratio: 5.3
Length: 1.31 m
Width: 0.85 m
Height: 0.87 m
Weight: 230 kg
Power output: 180 hp at 2100 rpm

8B
Bore: 120 mm
Stroke: 130 mm
Displacement: 11.76 lt
Compression ratio: 5.3
Length: 1.36 m
Width: 0.86 m
Height: 0.90 m
Weight: 236 kg
Power output: 200/235 hp at 2300 rpm

8F
Bore: 140 mm
Stroke: 150 mm
Displacement: 18.47 lt
Compression ratio: 5.3
Length: 1.32 m
Width: 0.89 m
Height: 0.88 m
Weight: 256 kg
Power output: 300 hp at 2100 rpm

 

Wolsely W.4A Viper
Type: 8-cylinder, upright, 90 degree Vee engine
Bore: 4.72 in (120 mm)
Stroke: 5.12 in (130 mm)
Displacement: 716.8 cu in (11.77 L)
Dry weight: 500 lb
Fuel system: Twin Zenith-Duplex carburettors
Cooling system: Liquid-cooled
Reduction gear: Direct drive, Right-hand tractor
Power output: 200 hp at 2,000 rpm (takeoff power)
Compression ratio: 5.3:1

 

 

 

 

 

 

 


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