The Coffman engine starter (also known as a "shotgun starter") was a starting system used on many piston engines in aircraft and armored vehicles of the 1930s and 1940s. It used a cordite cartridge to move a piston, which cranked the engine. The Coffman system was one of the most common brands; another was the Breeze cartridge system, which was produced under Coffman patents. Most American military aircraft and tanks which used radial engines were equipped with this system. Some versions of the Rolls-Royce Merlin engine used in the British Supermarine Spitfire used the Coffman system as a starter. The Hawker Typhoon and Hawker Tempest also used the Coffman system to start their Napier Sabre engines.
Cartridge starters used on a number of jet engines, including such engines as the Rolls-Royce Avon, which were used in the English Electric Canberra and Hawker Hunter aircraft, used a high gas volume cartridge driving a turbine instead of a piston.
Some Snowcat and similar vehicles used in extreme low temperatures were historically equipped with cartridge start.
The Coffman device used a large blank cartridge containing cordite that, when fired, pushed a piston forward. A screw thread driven by the piston engaged with the engine, turning it over. [1] This was in contrast with other type of cartridge starter which acted directly to drive the engine piston down and so turn the rest of the engine over, such as those used on the Field-Marshall agricultural diesel tractor.
The other systems used during the period were electric motors (such as those used in automobiles today), inertia starter (cranked either by hand or an electric motor) and compressed-air starters, which operated much like Coffman starters but were powered by pressurized air tanks.
Shotgun starters are composed of a breech, into which the cartridge is inserted, which is connected to the motor by a short steel pipe, which acts like a gun barrel. The blank cartridge fits into the breech, and is triggered either electrically or mechanically. When the aircraft's ignition is turned on and the cartridge is fired, high-velocity, high-pressure gas (~1,000 psi (6.9 MPa ) at ~600 ft/s (180 m/s)) shoots down the pipe, forcing the motor to spin and engage the starter ring gear on the engine, which is attached to the crankshaft.
Shotgun starters had several advantages over other starting systems in use at the time. Electric starters required large, heavy, and often troublesome batteries to be carried on board, or external charging equipment had to be located at every place where the vehicle was anticipated to operate. Inertia starters used a heavy wheel, usually made of brass, which was spun by a hand crank or electric motor, causing the spinning wheel to engage the starter ring gear. The Coffman system was more lightweight and compact than inertial starters or internal batteries, and it did not require any special auxiliary equipment, an important feature when operating in remote areas.
The primary disadvantages of the shotgun starter are the need to keep a stock of cartridges, one of which is used for each attempt to start, and the short time that the motor is spun by each cartridge. Compressed-air starters, which use the same type of motor, are usually recharged by an engine-driven compressor, negating the need to carry cartridges, but adding requirements for the compressor and air tank. Hybrid systems can be made simply by adding a cartridge breech or an air tank to an existing system. Air tanks can also be recharged from an external source in an emergency, such as a hand pump or a portable air compressor.
The Coffman starter was the most common brand of cartridge starters during the mid-1930s, and the name was used as a generic description. Advances in electrical technology have made shotgun starters obsolete for most uses.[ citation needed ]
The Rolls-Royce Merlin is a British liquid-cooled V-12 piston aero engine of 27-litre capacity. Rolls-Royce designed the engine and first ran it in 1933 as a private venture. Initially known as the PV-12, it was later called Merlin following the company convention of naming its four-stroke piston aero engines after birds of prey. The engine benefitted from the racing experiences of precursor engines in the 1930s.
A gas turbine, gas turbine engine, or also known by its old name internal combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part and are, in the direction of flow:
An auxiliary power unit (APU) is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft and naval ships as well as some large land vehicles. Aircraft APUs generally produce 115 V AC voltage at 400 Hz, to run the electrical systems of the aircraft; others can produce 28 V DC voltage. APUs can provide power through single or three-phase systems.
A starter is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power. Starters can be electric, pneumatic, or hydraulic. The starter can also be another internal-combustion engine in the case, for instance, of very large engines, or diesel engines in agricultural or excavation applications.
The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and a turbine. The compressed air from the compressor is heated by burning fuel in the combustion chamber and then allowed to expand through the turbine. The turbine exhaust is then expanded in the propelling nozzle where it is accelerated to high speed to provide thrust. Two engineers, Frank Whittle in the United Kingdom and Hans von Ohain in Germany, developed the concept independently into practical engines during the late 1930s.
An air-start system is a power source used to provide the initial rotation to start large diesel engines and gas turbines.
The Rolls-Royce Pegasus is a British turbofan engine originally designed by Bristol Siddeley. It was manufactured by Rolls-Royce plc. The engine is not only able to power a jet aircraft forward, but also to direct thrust downwards via swivelling nozzles. Lightly loaded aircraft equipped with this engine can manoeuvre like a helicopter. In particular, they can perform vertical takeoffs and landings. In US service, the engine is designated F402.
The Rolls-Royce Avon was the first axial flow jet engine designed and produced by Rolls-Royce. Introduced in 1950, the engine went on to become one of their most successful post-World War II engine designs. It was used in a wide variety of aircraft, both military and civilian, as well as versions for stationary and maritime power.
Hydrolock is an abnormal condition of any device which is designed to compress a gas by mechanically restraining it; most commonly the reciprocating internal combustion engine, the case this article refers to unless otherwise noted. Hydrolock occurs when a volume of liquid greater than the volume of the cylinder at its minimum enters the cylinder. Since liquids are nearly incompressible the piston cannot complete its travel; either the engine must stop rotating or a mechanical failure must occur.
A Hucks starter is an auxiliary power unit, almost always a lorry or truck, that provides initial power to start up piston aircraft engines. Invented by Royal Flying Corps Captain Bentfield Hucks, for whom it is named, the device served as a mechanical replacement for the groundcrew members who would have otherwise needed to spin an aircraft's propeller by hand as a part of the starting process, on aircraft engines not fitted with starters.
A free-piston engine is a linear, 'crankless' internal combustion engine, in which the piston motion is not controlled by a crankshaft but determined by the interaction of forces from the combustion chamber gases, a rebound device and a load device.
This article briefly describes the components and systems found in jet engines.
Internal combustion engines come in a wide variety of types, but have certain family resemblances, and thus share many common types of components.
A small engine is the general term for a wide range of small-displacement, low-powered internal combustion engines used to power lawn mowers, generators, concrete mixers and many other machines that require independent power sources. These engines often have simple designs, for example an air-cooled single-cylinder petrol engine with a pull-cord starter, capacitor discharge ignition and a gravity-fed carburettor.
The accessory drive is a gearbox that forms part of a gas turbine engine. Although not part of the engine's core, it drives the accessories – such as generators, pumps for fuel and lubrication oil, air compressors, hydraulic pumps and engine starters – that are otherwise essential for the operation of the engine or the aircraft on which it is mounted. Accessory drives on large engines handle between 400–500 hp.
The Guiberson A-1020 is a four-stroke diesel radial engine developed for use in aircraft and tanks.
Many variations of aircraft engine starting have been used since the Wright brothers made their first powered flight in 1903. The methods used have been designed for weight saving, simplicity of operation and reliability. Early piston engines were started by hand. Geared hand starting, electrical and cartridge-operated systems for larger engines were developed between the First and Second World Wars.
An internal combustion engine is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons, turbine blades, a rotor, or a nozzle. This force moves the component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.
Norbert Riedel was an engineer and entrepreneur.