H engine
Encyclopedia
An H engine is an engine configuration
in which the cylinder
s are aligned so that if viewed from the front, they appear to be in a vertical or horizontal letter H
.
An H engine can be viewed as two flat engine
s, one atop or beside the other. The "two engines" each have their own crankshaft
, which are then geared together at one end for power-take-off. The H configuration allows the building of multi-cylinder engines that are shorter than the alternatives, sometimes delivering advantages on aircraft. For race-car applications there is the disadvantage of a higher center of gravity
, not only because one crankshaft is located atop the other, but also because the engine must be high enough off the ground to allow clearance underneath for a row of exhaust pipes. The power-to-weight ratio
is not as good as simpler configurations employing one crankshaft. There is excellent mechanical balance, especially desirable and otherwise difficult to achieve in a four-cylinder engine.
Two straight engine
s can be similarly joined to provide a U engine
.
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produces water-cooled flat-four and flat-six "Horizontal" engines that are marketed as H4 and H6 (also thought to represent the configuration of the cylinders from a 'top down' POV as opposed to the traditional 'head-on' POV).
Engine configuration
Engine configuration is an engineering term for the layout of the major components of a reciprocating piston internal combustion engine. These components are the cylinders and crankshafts in particular but also, sometimes, the camshaft....
in which the cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
s are aligned so that if viewed from the front, they appear to be in a vertical or horizontal letter H
H
H .) is the eighth letter in the basic modern Latin alphabet.-History:The Semitic letter ⟨ח⟩ most likely represented the voiceless pharyngeal fricative . The form of the letter probably stood for a fence or posts....
.
An H engine can be viewed as two flat engine
Flat engine
A flat engine is an internal combustion engine with multiple pistons that move in a horizontal plane. Typically, the layout has cylinders arranged in two banks on either side of a single crankshaft and is sometimes known as the boxer, or horizontally opposed engine. The concept was patented in 1896...
s, one atop or beside the other. The "two engines" each have their own crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
, which are then geared together at one end for power-take-off. The H configuration allows the building of multi-cylinder engines that are shorter than the alternatives, sometimes delivering advantages on aircraft. For race-car applications there is the disadvantage of a higher center of gravity
Center of gravity
In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...
, not only because one crankshaft is located atop the other, but also because the engine must be high enough off the ground to allow clearance underneath for a row of exhaust pipes. The power-to-weight ratio
Power-to-weight ratio
Power-to-weight ratio is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources...
is not as good as simpler configurations employing one crankshaft. There is excellent mechanical balance, especially desirable and otherwise difficult to achieve in a four-cylinder engine.
Two straight engine
Straight engine
Usually found in four- and six-cylinder configurations, the straight engine, or inline engine is an internal-combustion engine with all cylinders aligned in one row, with no offset...
s can be similarly joined to provide a U engine
U engine
A U engine is a piston engine made up of two separate straight engines joined by gears or chains. It is similar to the H engine which couples two flat engines...
.
Aircraft engines
- LycomingLycoming EnginesLycoming Engines is a U.S. aircraft engine company, known primarily for its general aviation engines. For most of its history Lycoming has been part of the AVCO group as AVCO Lycoming. In 1987 AVCO was purchased by Textron to become Textron Lycoming...
- Lycoming H-2470 H-24 "hyper engineHyper engineThe hyper engine was a 1930s study project by the United States Army Air Corps to develop a high-performance aircraft engine that would be equal to or better than the aircraft and engines then under development in Europe...
"
- Lycoming H-2470 H-24 "hyper engine
- Fairey AviationFairey AviationThe Fairey Aviation Company Limited was a British aircraft manufacturer of the first half of the 20th century based in Hayes in Greater London and Heaton Chapel and RAF Ringway in Greater Manchester...
- Fairey Prince (H-16)Fairey Prince (H-16)|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9...
(1939) - 1,500 hp - Fairey MonarchFairey Monarch|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9...
(1939) - H-24 2,240 hp
- Fairey Prince (H-16)
- Klöckner-Humboldt-Deutz DZ 720Klöckner-Humboldt-Deutz DZ 710The Klöckner-Humboldt-Deutz DZ 710 was a German aircraft engine manufactured by Motorenfabrik Oberursel A.G. in the early 1940s. It was a 16-cylinder horizontally-opposed, two cycle diesel engine...
- H-32, 102.9 litres - Napier & SonNapier & SonD. Napier & Son Limited was a British engine and pre-Great War automobile manufacturer and one of the most important aircraft engine manufacturers in the early to mid-20th century...
, UK.- Napier RapierNapier Rapier|-See also:-Bibliography:* Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6....
(1929) - H-16 air-cooled vertical, 8.83 litres 340 hp - Napier DaggerNapier Dagger|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9...
(1934) - H-24, air-cooled vertical, 16.85 litres 890 hp, a development of the Rapier - Napier SabreNapier SabreThe Napier Sabre was a British H-24-cylinder, liquid cooled, sleeve valve, piston aero engine, designed by Major Frank Halford and built by Napier & Son during WWII...
(1938) - H-24, water-cooled horizontal sleeve valves, 36.7 litres 3,500 hp.
- Napier Rapier
- Pratt & WhitneyPratt & WhitneyPratt & Whitney is a U.S.-based aerospace manufacturer with global service operations. It is a subsidiary of United Technologies Corporation . Pratt & Whitney's aircraft engines are widely used in both civil aviation and military aviation. Its headquarters are in East Hartford, Connecticut, USA...
- XH-2240Pratt & Whitney X-1800|-See also:-External links:*...
- H-24, liquid-cooled, - XH-2600Pratt & Whitney X-1800|-See also:-External links:*...
- H-24, liquid-cooled, - XH-3130Pratt & Whitney XH-3130|-See also:-External links:*...
- H-24, liquid-cooled, - XH-3730Pratt & Whitney XH-3130|-See also:-External links:*...
- H-24, liquid-cooled,
- XH-2240
- Rolls-Royce Eagle (1944) - H-24, 46.2 litres, 3,200 hp.
Other engines
- The British Racing MotorsBritish Racing MotorsBritish Racing Motors was a British Formula One motor racing team. Founded in 1945, it raced from 1950 to 1977, competing in 197 Grands Prix and winning 17. In 1962, BRM won the Constructors' Title. At the same time, its driver, Graham Hill became World Champion...
(BRM) H-16 Formula One engine won the 1966 US Grand Prix with Jim ClarkJim ClarkJames "Jim" Clark, Jr OBE was a British Formula One racing driver from Scotland, who won two World Championships, in 1963 and 1965....
in a Lotus 43Lotus 43The Lotus 43 was a Formula One racing car designed by Colin Chapman for the 1966 season. It was partially based on the Lotus 38 Indycar, due to Chapman's experience at Indy with larger engine capacity and tyre/suspension setup. The car was designed in this way in response to new regulations which...
. As a racing-car engine it was hampered by a high center of gravityCenter of gravityIn physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...
, and it was heavy and complex, with gear-driven twin overhead cams for each of four cylinder heads, two gear-coupled crankshafts, and mechanical fuel injection. - The Brough Superior Golden DreamBrough Superior Golden DreamThe Brough Superior Golden Dream was designed and built by George Brough in Nottingham, England, in 1938. With its distinctive gold finish, this was to be the ultimate Brough Superior but production was stopped by the outbreak of War in 1939.-Development:...
motorcycle, first shown in 1938. A 1,000 cc H-4 design and a few units were produced in early 1939. Any development planned was interrupted by World War II and subsequent years of austerity. - WoolerWooler (motorcycles)Wooler was a British manufacturer of motorcycles and other vehicles, founded by engineer John Wooler in 1911 based in Alperton, Middlesex. The company became known for its unconventional designs which included several fore-and-aft twins, a vertical camshaft single cylinder machine, a...
built a motorcycle prototype with a similar configuration to the Brough Superior Golden Dream and exhibited it at the British International Motor ShowBritish International Motor ShowThe British International Motor Show is an automobile show held biennially in the United Kingdom. It is recognised as an international show by the Organisation Internationale des Constructeurs d'Automobiles. The 2008 was the last event with no news of a return of the British International Motor Show...
at Earls Court Exhibition CentreEarls Court Exhibition CentreThe Earls Court Exhibition Centre is an exhibition centre, conference and event venue located in west London, United Kingdom in the Royal Borough of Kensington and Chelsea . It is the largest exhibition venue in central London. It is served by two underground stations, Earl's Court and West...
in 1948 and again in 1951. This was replaced by a flat-four engined prototype at the 1953 show.
Other uses of H term
SubaruSubaru
; is the automobile manufacturing division of Japanese transportation conglomerate Fuji Heavy Industries .Subaru is internationally known for their use of the boxer engine layout popularized in cars by the Volkswagen Beetle and Porsche 911, in most of their vehicles above 1500 cc as well as...
produces water-cooled flat-four and flat-six "Horizontal" engines that are marketed as H4 and H6 (also thought to represent the configuration of the cylinders from a 'top down' POV as opposed to the traditional 'head-on' POV).