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34-538: The Franklin O-265 (company designation 6AC-264 ) was an American air-cooled aircraft engine of the early 1940s. The engine was of six-cylinder, horizontally-opposed layout and displaced 265 cu in (4 L). The power output ranged between 120 hp (89 kW) and 140 hp (104 kW) depending on variant. The 6ACG-264 featured a geared propeller drive . Data from Comparable engines Related lists Flat-six engine The advantages of

68-444: A boxer-four engine is for the left bank of cylinders to ignite one after another, followed by the right bank of cylinders (or vice versa), with the firing interval evenly spaced at 180 degrees. Traditionally, the exhausts from the two cylinders on each bank were merged, with the resulting uneven exhaust pulses causing a characteristic "flat-four burble" exhaust sound. The other common exhaust configuration (such as used by Subaru since

102-656: A flat-four engine. Tatra produced various flat-four engined model through the 1920s and 1930s. The 1936 Tatra T97 pioneered the rear-engined, air-cooled flat-four, backbone chassis layout (later used by the Volkswagen Beetle ), and at the same time, though unrelated, came the Steyr 50 from Austria, sporting a front boxer 4 engine with rear wheel drive. Also in 1936, English company Jowett expanded its model range from flat-twin engines to also include flat-four engines. Production of Jowett flat-four engines continued until 1954, when

136-510: A flat-six engine was the 1904–1907 Wilson-Pilcher 18/24 HP , which used an engine based on a flat-four engine with two cylinders added. The Wilson-Pilcher was a front-engined car with the crankshaft in-line with the chassis and the cylinders between the chassis rails. Reports on this car quote it as being "remarkably silent and smooth running" and "almost total absence of vibration". Two American manufacturers briefly produced cars with flat-six engines—the 1948 Tucker 48 (water-cooled, based on

170-1041: A naturally aspirated flat-six engine to a turbocharged flat-four engine, Porsche's first flat-four since the mid-1970s. This engine is produced in displacements of 2.0–2.5 L (122–153 cu in) and produces up to 365 hp (272 kW). Several reviewers criticised the Boxster/Cayman for an uninspiring engine sound. Most motorcycles with four-cylinder engines use an inline-four engine layout, however, several flat-four engine engines have been used in shaft drive motorcycles: Light aircraft commonly use flat-four engines with displacements up to 6.4 L (390 cu in) from manufacturers such as Rotax , Lycoming Engines , Continental Motors and Franklin Engine Company . For radio-controlled aircraft , flat-four engines with displacements of 40–50 cc (2.4–3.1 cu in) are produced by companies such as O.S. Engines . A notable recent flat-four aero-engine

204-500: A naturally aspirated version of the Subaru FA engine was used in the Toyota 86 (also called the "Subaru BRZ" and "Scion FR-S") rear-wheel drive sports coupe. This engine is water-cooled, has gasoline direct injection , produces 147 kW (197 hp) and has a displacement of 2.0 L (122 cu in). The 2016 Porsche Boxster/Cayman (982) mid-engined sports cars downsized from

238-399: A short engine length. Flat-four engine have successfully used air cooling , although air-cooled engines are noisier and have a lower power output than an equivalent engine with liquid cooling . In light aircraft, where lightness is of primary importance, air-cooling has traditionally been common. The downsides of boxer-four engines (compared with inline-four engines) are their extra width,

272-437: A slight rocking couple , but any resulting vibration is normally insufficient to require balance shafts. As with all four-stroke engines of four cylinders or fewer, the lack of overlap in the power strokes results in a pulsating delivery of torque to the flywheel , causing a torsional vibration along the crankshaft axis. Such vibration, if excessive, may be minimised using a harmonic damper . The typical firing order for

306-569: A water-cooled version called the Volkswagen Wasserboxer was introduced in the Volkswagen Transporter (T3) During the 1960s and 1970s, several manufacturers produced flat-four engines including the air-cooled Citroën flat-four engine , the water-cooled Alfa Romeo flat-four engine , the water-cooled Lancia flat-four engine and the water-cooled Subaru EA engine . Two important engines designed during this period, but never saw

340-421: Is able to have perfect primary and secondary balance . As in other six-cylinder engines, the overlapping of the power strokes of the different cylinders (with a firing interval of 120 degrees in a four-stroke engine) reduces the pulsating of the power delivery relative to that of similar engines with fewer cylinders. In a boxer configuration, a flat-six engine does not have a rocking couple . The symmetry of

374-406: Is not quite zero in practice because each cylinder pair is offset slightly from the other, or else they would clash at the crankshaft.) In this regard, the six cylinder boxer engine is the same as a flat-four boxer engine, which also does not experience any rocking couple. These characteristics result in low vibration for flat-six engines (as in straight-six engines ), especially when compared with

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408-656: The Jowett Javelin saloon and Jowett Jupiter sports models ended production. The longest production flat-four engine is the Volkswagen air-cooled engine , which was produced from 1938 until 2006 and was most famously used in the rear-engined 1938–2003 Volkswagen Beetle and 1950–1983 Volkswagen Transporter . This air-cooled engine was designed by Porsche and was also used in the 1948–1965 Porsche 356 , 1953–1956 Porsche 550 , 1965–1969 Porsche 912 and 1969–1976 Porsche 914 . In 1984, to comply with exhaust emissions regulations

442-528: The Pietenpol Air Camper homebuilt monoplane aircraft have used the air-cooled engine from the Chevrolet Corvair compact car. Compared with the engines used in cars, flat-six engines used by helicopters have large displacements and are low revving, producing more torque and less power. A notable recent flat-six aero-engine is the 4-litre side-valve Belgian D-Motor LF39 , a modular variant of

476-467: The Porsche 911 , a rear-engined sports car which has used flat-six engines exclusively since 1963. The engines were air-cooled until 1999, when Porsche started using water-cooled engines . Other Porsche models that use flat-six engines are the 1970–1972 Porsche 914/6 ( mid-engine ), the 1986–1993 Porsche 959 ( rear-engine ), and the 1996–2021 Porsche Boxster/Cayman (mid-engine). The first car to use

510-790: The Subaru ER27 , was added to the model range of the Subaru XT coupe. In 1991, the Subaru EG33 engine was used in the Subaru Alcyone SVX , the replacement for the Subaru XT. Following a hiatus of flat-6 engine production for four years, the Subaru EZ30 engine was introduced in the 2000 Subaru Legacy/Outback . The Subaru EZ36 engine was introduced in 2007 and was produced until 2019. All engines were used in front-engine cars with all-wheel drive, plus

544-501: The Subaru WRX sports sedan and its World Rally Car counterpart. Subaru's adoption of all-wheel drive was a factor in retaining the flat-four engine, since the shorter length of this engine assists in fitting the all-wheel drive components into the chassis. Although it is more expensive than an inline-four engine, the flat-four engine allows Subaru to build an all-wheel drive vehicle at little extra cost from two-wheel drive. In 2012,

578-423: The 2.7-litre flat-four D-Motor LF26 . Although the side-valve format has long been abandoned for most automotive applications because its combustion chamber is a bar to high engine rpm , the massively over-square (1.295:1) D-Motor is a very simple, low-revving, compact, reliable lightweight aero-engine (without the heavy (and bulky) complication of ohv valve-gear). The flat-six engine is often associated with

612-551: The BDC pair, so the net unbalanced torque pulse is the difference. The difference in TDC vs BDC inertial forces is explained in the Engine balance section. Boxer-four engines have been used in cars since 1897, especially by Volkswagen and Subaru. They have also occasionally been used in motorcycles and frequently in aircraft. Cessna and Piper use flat four engines from Lycoming and Continental in

646-482: The Franklin O-335) and the 1960–1969 Chevrolet Corvair (air-cooled). Both are rear-engined cars with rear-wheel drive. Chevrolet produced over 1.8 million Corvairs of various types and utilized a turbocharger on some models; one of the first uses of a turbocharger on a mass-produced automobile. Japanese manufacturer Subaru produced water-cooled flat-6 engines from 1988–1996 and 2000–2019. Their first flat-6 engine,

680-516: The XT and Alcyone SVX were also available with front-wheel drive. Most motorcycles use engines with four or fewer cylinders, however the Honda Gold Wing touring motorcycle has used a water-cooled flat-six engine since 1988. Initially, the engine had a displacement of 1.5 L (92 cu in), until it was enlarged to 1.8 L (110 cu in) in 2001. The Honda Valkyrie F6C (1997–2003)

714-401: The arrangement, in which one bank of three cylinders is mirrored by the other bank, means that there is no net force from any given mirrored cylinder pair along the axis of movement of the pistons. So not only is there no net primary or secondary reciprocating effect, there is no net turning force - moment - that would try to rotate the engine back and forth about its engine mountings. (The moment

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748-565: The bore and stroke were equal, with each being 95 mm (3.7 in). In 1902 the Buffum automobile was equipped with opposed four cylinder engines that were rated at 16 horsepower. Herbert H. Buffum produced an American Automobile called the Buffum in Abington, Massachusetts from 1903 to 1907. Having previously produced flat-twin engines, the 1926 Tatra 30 was the Czech company's first model powered by

782-492: The flat-six layout are good engine balance (for reduced vibration), a low center of gravity, short length (compared with an inline-six engine ) and being well suited to air-cooling. The disadvantages are a large width (which can limit the maximum steering angle when used in a front-engined car), a large intake manifold being required when a central carburetor is used, and duplication of the inlet and outlet connections for water-cooled engines. The first production flat-six engine

816-474: The historically more popular radial engines in small aircraft after World War II because they were less expensive to manufacture. The smaller frontal area compared with a radial engine also results in less drag. Some aircraft have used flat-six engines originally designed for cars. The Porsche PFM 3200 engine, produced from 1985 to 1991, was based on the engine used in the Porsche 911 sports car. Several examples of

850-702: The imbalances that are present in V6 engines with a 90-degree bank angle. Early flat-six engines include the Franklin O-265 which began production in 1940, and the Lycoming O-435 which began production in 1942. Several manufacturers use the letter O in their model codes for flat-layout engines as a designation for “opposed” cylinder layouts. The Franklin O-335 was used in the Bell 47 light helicopter. Flat engines largely replaced

884-439: The increased costs associated with having two cylinder heads instead of one, and the long exhaust manifold required to achieve evenly spaced exhaust pulses. Due to these factors, inline-four engines are more common in cars than are flat-four engines, and V6 engines are often used where larger displacements are required. The equal and opposing forces generated in a boxer-four engine result in perfect secondary balance (unlike

918-651: The light of day in series production, were the Morris 800cc side valve engine by Alec Issigonis in 1947 originally destined for the Morris Minor, and the Ferguson 2.2 litre SOHC engine by Claude Hill in 1966 as part of the R5 vehicle research project. By 2000, most manufacturers had replaced flat-four engines with inline-four engines. A notable exception is Subaru, with the water-cooled Subaru EJ engine being available in turbocharged form in

952-416: The mid-2000s) is to pair the cylinders with a firing interval offset of 360 degrees, in order to optimise the exhaust pulses . This configuration requires long exhaust manifolds, in order to pair the cylinders on opposite banks, and results in a less distinctive exhaust sound. In 1900, the first flat-four engine was produced by Benz & Cie , based on Benz's 1897 "contra" flat-twin engine. This engine

986-509: The most common civil aircraft in the world - the Cessna 172 , and Piper Cherokee , while many ultralight and LSA planes use versions of the Rotax 912 . In a flat-four engine, each pair of opposing pistons successively moves inwards together and outwards together. The advantages of the boxer-four layout are perfect secondary vibration (resulting in minimal vibration), a low centre of gravity , and

1020-403: The same time. A boxer-four engine has perfect primary and secondary balance, however, the two cylinder heads means the design is more expensive to produce than an inline-four engine . There is a minor, secondary unbalanced rotational torque pulse in the plane of the pistons, when a piston pair at one end of the engine is at TDC and the other pair at BDC. The TDC pair creates a torque greater than

1054-402: The unbalanced vertical forces produced by inline-four engines). Boxer-four engines are therefore better suited to displacements above 2.0 L (122 cu in), since they do not require balance shafts to reduce the secondary vibration. In a boxer engine, each cylinder is slightly offset from its opposing pair due to the distance between the crankpin journals. This offset gives rise to

Franklin O-265 - Misplaced Pages Continue

1088-580: Was a cruiser based on the GL1500 Gold Wing. The limited edition 2004 Valkyrie Rune was based on the GL1800. Flat-four engine A flat-four engine , also known as a horizontally opposed-four engine or boxer engine , is a four-cylinder piston engine with two banks of cylinders lying on opposite sides of a common crankshaft. The most common type of flat-four engine is the boxer-four engine , each pair of opposed pistons moves inwards and outwards at

1122-449: Was in the 1904 Wilson-Pilcher 18/24 HP car. The most notable use of flat-six engines is the Porsche 911 sports car, which has used flat-six engines continuously since 1963. Several other car manufacturers, including Subaru, have produced flat-six engines at times. Flat-six engines have also occasionally been used in motorcycles, and commonly in general aviation aircraft, along with the flat-four engine . A boxer-style flat-six engine

1156-488: Was used in Benz racing cars, produced 20 hp (15 kW), had a displacement of 5.4 L (330 cu in) and was designed by Georg Diehl. London company Wilson-Pilcher released its first car in 1901, which was powered by a flat-four engine. This engine was mounted longitudinally in the chassis, water-cooled, produced 9 hp (7 kW) and had a displacement of 2.4 L (146 cu in). Unusually for its day,

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