Bristol Jupiter

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Bristol Airplane Co. Ltd.
Jupiter.engine.arp.750pix.jpg
Jupiter
Production period: Late 1910s – 1935
Manufacturer: Bristol Airplane Co. Ltd.
Developing country: United KingdomUnited Kingdom United Kingdom
Working principle: Otto
Motor design: Radial engine
Cylinder: 9
Drilling: 146 mm
Hub: 165 mm
Displacement: 28,700 cm 3
Compression: 5.3: 1
Mixture preparation: Carburetor
Engine charging: mechanically
Cooling system: Air cooling
Power: 430 kW
Dimensions: 330 kg
Previous model: none
Successor: Mercury

The Bristol Jupiter was an air-cooled nine-cylinder radial engine . From 1918 to 1935, the British Bristol Airplane Co. Ltd. and various licensees built over 7100 copies of this aero engine and used it in a large number of aircraft types.

history

Jupiter was developed by Roy Fedden at Cosmos Engineering Co. shortly before the end of the First World War . Due to budget cuts in military spending after the end of the war, Cosmos Engineering Co. became insolvent in 1920 . Bristol Airplane Co. Ltd. bought the company, including all patents, for 15,000 pounds sterling and the team of chief designer Roy Fedden further developed the engine with the four-valve technology, which was unusual for radial engines at the time. The Jupiter engine was a great commercial success and was considered one of the most reliable aircraft engines ever. In the 1920s and 1930s, the type was continuously improved and from 1927 variants with mechanical charging were used, the last version of which was the Jupiter XF .

The engine was used in a number of civil aircraft. Militarily it was used by the Bristol Bulldog , the Gloster Gamecock and the Boulton & Paul Sidestrand . It was also an extremely sought-after engine when it came to propelling prototypes.

Fedden began developing a successor in 1925. With a shorter stroke and therefore less displacement, but with supercharging, the nine-cylinder Bristol Mercury was completed in 1927 . The charged Jupiter was named Bristol Pegasus in 1931 . Bristol built the Mercury and Pegasus types until 1944; Jupiter production ended in 1935 with the appearance of more powerful supercharged engines.

Licensed buildings

There have been a number of licenses . In total, licenses were sold to 14 states. The best known are the engines manufactured in France as Gnôme-Rhône  9 Jupiter and in the Soviet Union as M-22 , which were used in the Polikarpow I-16 , among others . In Germany , Siemens & Halske acquired a license to build the engine in 1929 , but not for the Bristol original, but for the Gnôme-Rhône 9, which went into production as the Siemens Sh 20 / Sh 21 . Among the aircraft that were equipped with it, belonged example, the Focke-Wulf A 38 "Seagull", the twin-engine Dornier Wal , the four-engine Dornier Do R "Superwal" and initially also the Dornier Do X . The successor Sh 22 (= Bramo  322 ), built from 1930 onwards, was further developed into the Bramo 323 and built until 1944. In Japan , the Nakajima factories bought a license in 1924. The Saurer had a license for Switzerland . In Czechoslovakia , Walter acquired the reproduction rights for the Jupiter VI in 1927 and the Jupiter VIII / R in 1928 .

construction

The cylinder of a Jupiter VI, the ribbed steel bushing dark, the light-metal cylinder head lighter

Jupiter was a single row nine-cylinder radial engine, which after four stroke - Otto method worked. It had four-valve cylinder heads and an OHV valve control .

The crankcase was split at the level of the cylinder axis, the housing parts were drop-forged from a light metal alloy and machine reworked and sandblasted. The front half of the housing housed the valve control (the cam drum ) and - depending on the version - an air screw gear, the rear half an annular channel for distributing the fresh gas. A three-thread, cast aluminum helix was inserted into this, which ensured that the mixture produced by a triple carburettor was evenly distributed over the individual cylinder intake pipes. One carburetor unit each supplied three cylinders.

The cylinder liners were machined from steel forgings. In a kind of sack cylinder, the combustion chamber floor is an integral part of the bushing; the four valve seats are also located in this steel floor. The cooling fins were in the socket casing is rotated , the ribs on the bad cooled by the airstream back are higher. In this elaborate manufacturing process, the 88 lbs. heavy cylinder blank 70 lbs. Material worked away until the 18 lbs. heavy finished cylinder liner was left.

The light-alloy cylinder heads were screwed onto the flat- ground top of the combustion chamber floor; these housed the gas ducts, the valve guides and the rocker arm bracket. This design saved the cylinder head gasket in the traditional sense, only in the transitions between the two inlet ducts from the light metal head to the steel base were sealing and fitting rings made of phosphor bronze . The valve was actuated by two push rods running parallel one behind the other, which led radially from the front part of the housing with the cam drum to the rocker arms. The valve train was completely open and not integrated into the oil circuit. The rocker arm bracket was only mounted on the rear side in the cylinder head, the front mounting point was a tension strut that led to the crankcase. This design compensated for the linear expansion of the cylinder caused by the heating during operation and ensured an almost constant valve clearance regardless of the engine temperature.

Technical specifications

  • Engine type: air-cooled 9-cylinder radial engine with and without propeller gear , (Jupiter VII with charger)
  • Bore : 5.75 inches (146 mm)
  • Stroke : 7.5 inches (190.5 mm); Mercury: 6.5 inches (165mm)
  • Displacement : 28.7 l (Mercury 24.9 l)
  • Weight: 330 kg (Jupiter XFA with loader: 451 kg); Mercury: 438 kg
  • Gas change: OHV, 4 valves
  • Continuous power: 442 hp at 1575 min -1
  • Start Power : 585 hp at 1950 min -1
  • Compression ratio : 5.3: 1

See also

literature

  • Hans Giger: piston aircraft engines. Motorbuchverlag, ISBN 3-613-01089-5 .
  • JA Gilles: Aircraft engines 1910–1918. Publisher ES Mittler & Sohn, 1971.

Web links

Commons : Bristol Jupiter  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Schweizerische Bauzeitung , Volume 91/92 (1928), p. 196 , accessed from the ETH Library on May 6, 2015
  2. ↑ Vaclav Nemecek: Československá letadla . Naše Vojsko, Prague 1968, p. 316 (Czech).