A turboshaft engine is a form of gas turbine that is optimized to produce shaft horsepower rather than jet thrust . In concept, turboshaft engines are very similar to turbojets , with additional turbine expansion to extract heat energy from the exhaust and convert it into output shaft power. They are even more similar to turboprops , with only minor differences, and a single engine is often sold in both forms.
31-661: The Rolls-Royce Gem is a turboshaft engine developed specifically for the Westland Lynx helicopter in the 1970s. The design started off at de Havilland Engine division (hence the name starting with "G") and passed to Bristol Siddeley as the BS.360 . Rolls-Royce bought out Bristol Siddeley in 1966 and after it dropped the Bristol Siddeley identity the engine became the RS.360 . The Gem's three-shaft engine configuration
62-413: A gear reduction system, and the shaft output. The gas generator creates the hot expanding gases to drive the power section. Depending on the design, the engine accessories may be driven either by the gas generator or by the power section. In most designs, the gas generator and power section are mechanically separate so they can each rotate at different speeds appropriate for the conditions, referred to as
93-544: A ' free power turbine '. A free power turbine can be an extremely useful design feature for vehicles, as it allows the design to forgo the weight and cost of complex multiple-ratio transmissions and clutches . An unusual example of the turboshaft principle is the Pratt & Whitney F135 -PW-600 turbofan engine for the STOVL Lockheed F-35B Lightning II – in conventional mode it operates as
124-570: A combination starter/generator for APU starting and electrical power generation to reduce complexity. On the Boeing 787 , an aircraft which has greater reliance on its electrical systems, the APU delivers only electricity to the aircraft. The absence of a pneumatic system simplifies the design, but high demand for electricity requires heavier generators. Onboard solid oxide fuel cell ( SOFC ) APUs are being researched. The market of Auxiliary power units
155-645: A niche as a powerplant for turboshaft-driven helicopters in the 1950s. In 1950, Turbomeca used its work from the 782 to develop the larger 280-shp Artouste , which was widely used on the Aérospatiale Alouette II and other helicopters. This was following the experimental installation of a Boeing T50 turboshaft in an example of the Kaman K-225 synchropter on December 11, 1951, as the world's first-ever turboshaft-powered helicopter of any type to fly. The T-80 tank, which entered service with
186-517: A sustained high power output, high reliability, small size, and light weight. These include helicopters , auxiliary power units , boats and ships , tanks , hovercraft , and stationary equipment. A turboshaft engine may be made up of two major parts assemblies: the 'gas generator' and the 'power section'. The gas generator consists of the compressor , combustion chambers with ignitors and fuel nozzles , and one or more stages of turbine . The power section consists of additional stages of turbines,
217-711: A turbofan, but when powering the Rolls-Royce LiftSystem , it switches partially to turboshaft mode to send 29,000 horsepower forward through a shaft and partially to turbofan mode to continue to send thrust to the main engine's fan and rear nozzle. Large helicopters use two or three turboshaft engines. The Mil Mi-26 uses two Lotarev D-136 at 11,400 hp each, while the Sikorsky CH-53E Super Stallion uses three General Electric T64 at 4,380 hp each. The first gas turbine engine considered for an armoured fighting vehicle,
248-484: 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 (rather than 50/60 Hz in mains supply), 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 jet fuel starter (JFS)
279-558: Is a similar device to an APU but directly linked to the main engine and started by an onboard compressed air bottle. During World War I , the British Coastal class blimps , one of several types of airship operated by the Royal Navy , carried a 1.75 horsepower (1.30 kW) ABC auxiliary engine. These powered a generator for the craft's radio transmitter and, in an emergency, could power an auxiliary air blower. One of
310-472: Is dominated by Honeywell , followed by Pratt & Whitney , Motorsich and other manufacturers such as PBS Velká Bíteš , Safran Power Units , Aerosila and Klimov . Local manufacturers include Bet Shemesh Engines and Hanwha Aerospace . The 2018 market share varied according to the application platforms: On June 4, 2018, Boeing and Safran announced their 50–50 partnership to design, build and service APUs after regulatory and antitrust clearance in
341-471: Is rather unusual for turboshaft/turboprop engines. Basic arrangement is a four-stage axial LP (Low Pressure) compressor, driven by a single stage LP turbine, supercharging a centrifugal HP (High Pressure) compressor, driven by a single stage HP turbine. Power from a two-stage free (power) turbine is delivered to the load via a third shaft. A reverse flow combustor is featured. The Gem 42 develops 1,000 shp (750 kW) at Take-off, Sea Level Static, ISA, but
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#1732783110346372-413: Is the gas-generator portion of the engine and produces all the shaft power for the APU. In this section of the engine, air and fuel are mixed, compressed and ignited to create hot and expanding gases. This gas is highly energetic and is used to spin the turbine, which in turn powers other sections of the engine, such as auxiliary gearboxes, pumps, electrical generators, and in the case of a turbo fan engine,
403-720: Is the sole supplier for the Airbus A350 , the Boeing 777 and all single-aisles : the Boeing 737 MAX , Airbus A220 (formerly Bombardier CSeries), Comac C919 , Irkut MC-21 and Airbus A320neo since Airbus eliminated the P&;WC APS3200 option. P&WC claims the remaining 35% with the Airbus A380 , Boeing 787 and Boeing 747-8 . It should take at least a decade for the Boeing/Safran JV to reach $ 100 million in service revenue. The 2017 market for production
434-568: The GT 101 which was based on the BMW 003 turbojet, was tested in a Panther tank in mid-1944. The first turboshaft engine for rotorcraft was built by the French engine firm Turbomeca , led by its founder Joseph Szydlowski . In 1948, they built the first French-designed turbine engine, the 100-shp 782. Originally conceived as an auxiliary power unit , it was soon adapted to aircraft propulsion, and found
465-661: The Soviet Army in 1976, was the first tank to use a gas turbine as its main engine. Since 1980 the US Army has operated the M1 Abrams tank, which also has a gas turbine engine. (Most tanks use reciprocating piston diesel engines.) The Swedish Stridsvagn 103 was the first tank to utilize a gas turbine as a secondary, high-horsepower "sprint" engine to augment its primary piston engine's performance. The turboshaft engines used in all these tanks have considerably fewer parts than
496-530: The German engineer Norbert Riedel . It consisted of a 10 horsepower (7.5 kW) two-stroke flat engine , which for the Junkers Jumo 004 design was hidden in the intake diverter, essentially functioning as a pioneering example of an auxiliary power unit for starting a jet engine. A hole in the extreme nose of the diverter contained a manual pull-handle which started the piston engine, which in turn rotated
527-577: The Jumo 004. For reduction it had an integrated planetary gear . It was produced by Victoria in Nuremberg and served as a mechanical APU-style starter for all three German jet engine designs to have made it to at least the prototype stage before May 1945 – the Junkers Jumo 004 , the BMW 003 (which uniquely appears to use an electric starter for the Riedel APU), and the prototypes (19 built) of
558-564: The Maximum Contingency Rating (MCR) is 1,120 shp (840 kW). Until recently all versions of the Lynx have been Gem powered. However, now that Rolls-Royce owns Allison , it has been marketing the more modern LHTEC T800 , developed jointly with Honeywell . Data from Rolls-Royce Comparable engines Related lists Turboshaft Turboshaft engines are commonly used in applications that require
589-550: The Shuttle's three engines and control of their large valves, and for movement of the control surfaces . During landing, they moved the control surfaces, lowered the wheels, and powered the brakes and nose-wheel steering. Landing could be accomplished with only one APU working. In the early years of the Shuttle there were problems with APU reliability, with malfunctions on three of the first nine Shuttle missions. APUs are fitted to some tanks to provide electrical power without
620-474: The compressor. Two spark plug access ports existed in the Jumo 004's intake diverter to service the Riedel unit's cylinders in situ, for maintenance purposes. Two small "premix" tanks for the Riedel's petrol/ oil fuel were fitted in the annular intake. The engine was considered an extreme short stroke (bore / stroke: 70 mm / 35 mm = 2:1) design so it could fit within the intake diverter of jet engines like
651-531: The first military fixed-wing aircraft to use an APU was the British, World War 1, Supermarine Nighthawk , an anti-Zeppelin night fighter . During World War II , a number of large American military aircraft were fitted with APUs. These were typically known as putt–putts , even in official training documents. The putt-putt on the B-29 Superfortress bomber was fitted in the unpressurised section at
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#1732783110346682-569: The high fuel consumption and large infrared signature of the main engine. As early as World War II, the American M4 Sherman had a small, piston-engine powered APU for charging the tank's batteries, a feature the Soviet-produced T-34 tank did not have. A refrigerated or frozen food semi trailer or train car may be equipped with an independent APU and fuel tank to maintain low temperatures while in transit, without
713-404: The main fan. The load compressor is generally a shaft-mounted compressor that provides pneumatic power for the aircraft, though some APUs extract bleed air from the power section compressor. There are two actuated devices to help control the flow of air: the inlet guide vanes that regulate airflow to the load compressor and the surge control valve that maintains stable or surge-free operation of
744-588: The more advanced Heinkel HeS 011 engine, which mounted it just above the intake passage in the Heinkel-crafted sheetmetal of the engine nacelle nose. The Boeing 727 in 1963 was the first jetliner to feature a gas turbine APU, allowing it to operate at smaller airports, independent from ground facilities. The APU can be identified on many modern airliners by an exhaust pipe at the aircraft's tail. A typical gas-turbine APU for commercial transport aircraft comprises three main sections: The power section
775-535: The need for an external transport-supplied power source. On some older diesel engined-equipment, a small gasoline engine (often called a "pony engine") was used instead of an electric motor to start the main engine. The exhaust path of the pony engine was typically arranged so as to warm the intake manifold of the diesel, to ease starting in colder weather. These were primarily used on large pieces of construction equipment. In recent years, truck and fuel cell manufacturers have teamed up to create, test and demonstrate
806-416: The piston engines they replace or supplement, mechanically are very reliable, produce reduced exterior noise, and run on virtually any fuel: petrol (gasoline), diesel fuel , and aviation fuels. However, turboshaft engines have significantly higher fuel consumption than the diesel engines that are used in the majority of modern main battle tanks. Auxiliary power unit An auxiliary power unit (APU) ,
837-502: The rear of the aircraft. Various models of four-stroke, Flat-twin or V-twin engines were used. The 7 horsepower (5.2 kW) engine drove a P2 , DC generator, rated 28.5 Volts and 200 Amps (several of the same P2 generators, driven by the main engines , were the B-29's DC power source in flight). The putt-putt provided power for starting the main engines and was used after take-off to a height of 10,000 feet (3,000 m). The putt-putt
868-478: The second half of 2018. Boeing produced several hundred T50 / T60 small turboshafts and their derivatives in the early 1960s. Safran produces helicopters and business jets APUs but stopped the large APUs since Labinal exited the APIC joint venture with Sundstrand in 1996. This could threaten the dominance of Honeywell and United Technologies . Honeywell has a 65% share of the mainliner APU market and
899-403: The turbo machine. The gearbox transfers power from the main shaft of the engine to an oil-cooled generator for electrical power. Within the gearbox, power is also transferred to engine accessories such as the fuel control unit, the lubrication module, and cooling fan. There is also a starter motor connected through the gear train to perform the starting function of the APU. Some APU designs use
930-659: Was restarted when the B-29 was descending to land. Some models of the B-24 Liberator had a putt–putt fitted at the front of the aircraft, inside the nose-wheel compartment. Some models of the Douglas C-47 Skytrain transport aircraft carried a putt-putt under the cockpit floor. The first German jet engines built during the Second World War used a mechanical APU starting system designed by
961-507: Was worth $ 800 million (88% civil and 12% military), while the MRO market was worth $ 2.4 billion, spread equally between civil and military. The Space Shuttle APUs provided hydraulic pressure. The Space Shuttle had three redundant APUs, powered by hydrazine fuel. They were only powered up for ascent, re-entry , and landing. During ascent, the APUs provided hydraulic power for gimballing of