An obturator ring was a type of piston ring used in World War I aero engines for improved sealing in the presence of cylinder distortion.
The cylinders of rotary aircraft engines of World War I (engines with the crankshaft fixed to the airframe and rotating cylinders) were notoriously difficult to keep cool leading to thermal distortion. To keep the weight down they had very thin-wall (1.5 mm) steel cylinders. Obturator rings, made of bronze in the early Gnome engines, could flex to the shape of the cylinder. Wear on the rings was considerable. Engines needed to be overhauled about every 20 hours. The reliability of Gnome engines license-built by The British Gnome and Le Rhone Engine Co. gave an overhaul life of about 80 hours mainly as a result using a special tool to roll the 'L' section obturator rings. The problem of thermal distortion was effectively cured on the Bentley BR1 engine by using aluminium cylinders, for good thermal conductivity, with cast iron liners shrunk in.
An 'L' section obturator ring is shown in Patent US 1378109A - "Obturator ring".
The rotary engine is an early type of internal combustion engine, usually designed with an odd number of cylinders per row in a radial configuration, in which the crankshaft remained stationary in operation, with the entire crankcase and its attached cylinders rotating around it as a unit. Its main application was in aviation, although it also saw use before its primary aviation role, in a few early motorcycles and automobiles.
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is called a "star engine" in some other languages.
The sleeve valve is a type of valve mechanism for piston engines, distinct from the usual poppet valve. Sleeve valve engines saw use in a number of pre-World War II luxury cars and in the United States in the Willys-Knight car and light truck. They subsequently fell from use due to advances in poppet-valve technology, including sodium cooling, and the Knight system double sleeve engine's tendency to burn a lot of lubricating oil or to seize due to lack of it. The Scottish Argyll company used its own, much simpler and more efficient, single sleeve system (Burt-McCollum) in its cars, a system which, after extensive development, saw substantial use in British aircraft engines of the 1940s, such as the Napier Sabre, Bristol Hercules, Centaurus, and the promising but never mass-produced Rolls-Royce Crecy, only to be supplanted by the jet engines.
The Bristol Hercules is a 14-cylinder two-row radial aircraft engine designed by Sir Roy Fedden and produced by the Bristol Engine Company starting in 1939. It was the most numerous of their single sleeve valve designs, powering many aircraft in the mid-World War II timeframe.
The Monosoupape, was a rotary engine design first introduced in 1913 by Gnome Engine Company. It used a clever arrangement of internal transfer ports and a single pushrod-operated exhaust valve to replace the many moving parts found on more conventional rotary engines, and made the Monosoupape engines some of the most reliable of the era. British aircraft designer Thomas Sopwith described the Monosoupape as "one of the greatest single advances in aviation".
Clerget was the name given to a series of early rotary aircraft engine types of the World War I era that were designed by Pierre Clerget. Manufactured in France by Clerget-Blin and in Great Britain by Gwynnes Limited they were used on such aircraft as the Sopwith Camel and Vickers Gunbus.
Gnome et Rhône was a major French aircraft engine manufacturer. Between 1914 and 1918 they produced 25,000 of their 9-cylinder Delta and Le Rhône 110 hp (81 kW) rotary designs, while another 75,000 were produced by various licensees. These engines powered the majority of aircraft in the first half of the war, both Allied designs as well as German examples produced by Motorenfabrik Oberursel.
The Rolls-Royce Crecy was a British experimental two-stroke, 90-degree, V12, liquid-cooled aero-engine of 1,593.4 cu.in capacity, featuring sleeve valves and direct petrol injection. Initially intended for a high-speed "sprint" interceptor fighter, the Crecy was later seen as an economical high-altitude long-range powerplant. Developed between 1941 and 1946, it was among the most advanced two-stroke aero-engines ever built. The engine never reached flight trials and the project was cancelled in December 1945, overtaken by the progress of jet engine development.
A piston ring is a metallic split ring that is attached to the outer diameter of a piston in an internal combustion engine or steam engine.
Rolls-Royce produced a range of piston engine types for aircraft use in the first half of the 20th century. Production of own-design engines ceased in 1955 with the last versions of the Griffon; licensed production of Teledyne Continental Motors general aviation engines was carried out by the company in the 1960s and 1970s.
Axial engines are a type of reciprocating engine with pistons arranged around an output shaft with their axes parallel to the shaft. Barrel refers to the cylindrical shape of the cylinder group whilst the Z-crank alludes to the shape of the crankshaft.
The Bentley BR.1 was a British rotary aircraft engine of the First World War. Designed by the motor car engine designer W. O. Bentley, the BR.1 was built in large numbers, being one of the main powerplants of the Sopwith Camel.
The Gnome 7 Omega is a French seven-cylinder, air-cooled aero engine produced by Gnome et Rhône. It was shown at the Paris Aero Salon held in December 1908 and was first flown in 1909. It was the world's first aviation rotary engine produced in quantity. Its introduction revolutionized the aviation industry and it was used by many early aircraft. It produced 37 kW (50 hp) from its 8 L (490 cu in) engine capacity. A Gnome Omega engine powers the 1912 Blackburn Monoplane, owned and operated by the Shuttleworth Collection, the oldest known airworthy British-designed aeroplane worldwide. A two-row version of the same engine was also produced, known as the Gnome 14 Omega-Omega or Gnome 100 hp. The prototype Omega engine still exists, and is on display at the United States' National Air and Space Museum.
The Gnome 9 Delta was a French designed, nine-cylinder, air-cooled rotary aero engine that was produced under license in Britain. Powering several World War I era aircraft types it produced 100 hp (75 kW) from its capacity of 16 litres (980 cu in).
The Gnome 7 Lambda was a French designed, seven-cylinder, air-cooled rotary aero engine that was produced under license in Britain and Germany. Powering several World War I-era aircraft types it was claimed to produce 80 horsepower (60 kW) from its capacity of 12 litres although recorded figures are lower.
The Gnome 7 Gamma was a French designed, seven-cylinder, air-cooled rotary aero engine. Powering several pre-World War I era aircraft types it produced 70 horsepower (52 kW) from its capacity of 12 litres.
The Clerget 7Z was a seven-cylinder rotary aircraft engine of the World War I era designed by Pierre Clerget. First appearing in 1911 it was nominally rated at 80 horsepower (60 kW). 347 examples were jointly built in Britain by Gordon Watney & Co Ltd of Weybridge and Gwynnes Limited of Hammersmith.
Gyro Motor Company was an American aircraft engine manufacturer.
The Gnome 7Σ Sigma is a French seven-cylinder, air-cooled rotary aero engine.
The Goupy Type B was a staggered biplane designed by Ambroise Goupy in the early 1910s.