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Encyclopedia > Turboprop
A schematic diagram showing the operation of a turboprop engine.
A schematic diagram showing the operation of a turboprop engine.
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The P&W PT6, one of the most popular turboprop engines.

A Turboprop engine is a type of gas turbine engine which uses most of its power to drive a propeller. The propeller of a turboprop is very similar to that used by piston or reciprocating engines, but turboprops usually use a constant velocity propeller. Turboprop engines are generally used on small or slow subsonic aircraft, but some aircraft outfitted with turboprops have cruising speeds in excess of 500 kts (925 Km/h). Image File history File links Turboprop_operation. ... Image File history File links Turboprop_operation. ... Image File history File links Turboprop_P&W_PT6A-67D.jpg‎ Reason for deletion request: File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Turboprop Pratt & Whitney Canada PT6 ... Image File history File links Turboprop_P&W_PT6A-67D.jpg‎ Reason for deletion request: File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Turboprop Pratt & Whitney Canada PT6 ... The PT6 is a turboprop aircraft engine manufactured by Pratt & Whitney Canada and is the most popular turboprop in history [1]. It has an unusual design in that the air enters from the rear of the engine and the power section is at the front. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... piston + connecting rod Components of a typical, four stroke cycle, DOHC piston engine. ... Components of a typical, four stroke cycle, DOHC piston engine. ... A knot is a unit of speed, abbreviated kt or kn. ...


A turboprop consists of an intake, compressor, combustor, turbine and a propelling nozzle. Air is drawn into the intake and compressed by the compressor. Fuel is then added to the compressed air in the combustor. The hot combustion gases expand through the turbine, to provide power to the turbine. Part of this power goes to the compressor, and the rest, through the reduction gearing, to the propeller. Further expansion of the gases occurs in the propelling nozzle, where the gasses are expelled, providing approximately 25% of the thrust. Compressor has several meanings: A gas compressor is a mechanical device that takes in a gas and increases its pressure by squeezing a volume of it into a smaller volume. ... A ring of can type combustors circles the mid section of this gas turbine. ... WWII era steam turbine used for ship propulsion. ... Propulsion method may refer to a number of different articles: For a list of space transport methods, see spacecraft propulsion. ... Rocket Nozzle A nozzle is a mechanical device designed to control the characteristics of a fluid flow as it exits from an enclosed chamber into some medium. ...


A turboprop engine is similar to a turbojet, but has additional fan blades in the turbine stage to recover more power from the engine to turn the propeller. Turbojets are the simplest and oldest kind of general purpose jet engine. ... WWII era steam turbine used for ship propulsion. ...


In a turboprop much of the jet thrust is sacrificed in favor of shaftpower, which is obtained by extracting additional power (to that necessary to drive the compressor) from the turbine expansion process. While the power turbine may be integral with the gas generator section, many turboprops today feature a Free Power Turbine, on a separate coaxial shaft. This enables the propeller to rotate freely, independent of compressor speed. Owing to the additional expansion in the turbine system, the residual energy in the jet is fairly low (<10% of total thrust, including that of the propeller).


Because the propeller is very much larger in diameter than the power turbine, the tip speed of the propeller can become supersonic. Consequently, to prevent this, a speed reduction gearbox is inserted between the power turbine and propeller shafts. The gearbox is part of the engine, whereas in a turboshaft the (helicopter) rotor reduction gearbox is remote from the engine. Schematic diagram showing the operation of a simplified turboshaft engine. ... The Bell 206 of Canadian Helicopters Robinson Helicopter Company (USA) R44, a four seat development of the R22 A helicopter is an aircraft which is lifted and propelled by one or more horizontal rotors, Helicopters are classified as rotary-wing aircraft to distinguish them from conventional fixed-wing aircraft. ...


Residual thrust on a turboshaft is avoided by further expansion in the turbine system and/or truncating and turning the exhaust through 90 degrees, to produce two opposing jets.


Apart from the above, there is very little difference between a turboprop and a turboshaft.


Turboprops are very efficient at modest flight speeds (below 724 km/h or 450mph), because the jet velocity of the propeller (and exhaust) is relatively low. Consequently, small commuter aircraft and military transports tend to feature turboprop engines. Although turboprops are used in some General Aviation applications, their high price deters more widespread acceptance except for very high performance STOL applications. One of the most common turboprop military aircraft is the C-130 Hercules transport. STOL is an acronym for Short Take-Off and Landing, used in the aircraft industry to describe airplanes with very short runway requirements. ... The Lockheed C-130 Hercules is a four-engine turboprop cargo aircraft and the main tactical airlifter for military forces worldwide. ...


While most modern turbojet and turbofan engines use axial-flow compressors, turboprop engines usually contain at least one stage of centrifugal compression, because of the small size of the engines. Turbojets are the simplest and oldest kind of general purpose jet engine. ... CFM56-3 turbofan, lower half, side view. ... The axial flow compressor is an improvement on the centrifugal compressor previously used in turbine engines,though small and micro turbines use centrifugal compressors with relative advantages (in terms of pressure ratios achieveable per stage of compression). ... A centrifugal compressor, also called a radial blower, squirrel cage, or squirrel wheel compressor, consists of an axle to which is mounted a cylindrical assembly of compressor blades. ...


Propellers lose efficiency as aircraft speed increases, which is why turboprops are not used on higher-speed aircraft.


History

A Rolls-Royce RB.50 Trent on a test rig at Hucknall, in March 1945
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A Rolls-Royce RB.50 Trent on a test rig at Hucknall, in March 1945

The world's first Turboprop was the 'Jendrassik Cs-1' designed by the Hungarian machanical engineer György Jendrassik. It was produced and tested in the Ganz Factory in Budapest between 1939 and 1942. It was planned to fit to the Varga RMI-1 X/H twin-engined reconnaissance bomber designed by László Varga in 1940, but the programme was cancelled. Jendrassik had also designed a small-scale 75 kW turboprop in 1937. ImageMetadata File history File links Rolls-Royce_RB50_Trent_Turboprop_On_Test_Rig_At_Hucknall. ... ImageMetadata File history File links Rolls-Royce_RB50_Trent_Turboprop_On_Test_Rig_At_Hucknall. ... The Jendrassik Cs-1 was the worlds first working turboprop engine. ... György Jendrassik (1898-1954) was born in Budapest, Hungary. ...


The first British turboprop engine was the Rolls-Royce RB.50 Trent, a converted Derwent II fitted with reduction gear and a Rotol 7' 11" five-bladed propeller. Two Trents were fitted to Gloster Meteor EE227 — the sole "Trent-Meteor" — which became the first relatively reliable turboprop powered aircraft. From their experience with the Trent, Rolls-Royce developed the Dart, which became one of the most reliable turboprop engines ever built. Dart production continued for more than fifty years. Rolls-Royce plc is the second-largest aircraft engine maker in the world, behind General Electric Aviation. ... Rolls-Royce Trent 900 on A380 prototype Rolls Royce Trent is a family of high-bypass turbofan engines manufactured by Rolls-Royce. ... The Derwent was the second jet engine design to be put into production by Rolls-Royce. ... Rotol was a British company set up jointly by Rolls-Royce and the Bristol Aeroplane Company during World War Two for the manufacture of aircraft propellers. ... The Gloster Meteor was the first jet fighter aircraft of the British Royal Air Force, introduced into service only weeks after the Third Reichs Messerschmitt Me 262, in August 1944 during World War II. It was thus the second fighter jet in history and the first of the WWII... The Rolls Royce Dart was a long-lived turboprop engine. ...


While the Soviet Union had the technology to create a jet powered strategic bomber comparable to the Boeing B-52, they instead produced the Tu-95 Bear which uses 4 contra-rotating propellers with supersonic tip speeds to achieve maximum cruise speeds in excess of 575 mph, faster than many of the first jet aircraft, and comparable to jet cruising speeds for most missions. The Bear would serve as their most successful long range combat and surveillance aircraft and symbol of Soviet power projection throughout the end of the 20th century. The USA would incorporate contra-rotating turboprop engines in experimental tail-sitting VTOL and fighter aircraft during the 1950s, but none would be adopted into service. The Boeing B-52 Stratofortress is a long-range strategic bomber flown by the United States Air Force since 1955, replacing the Convair B-36. ... The Tupolev Tu-95 (NATO reporting name Bear) is the most successful Tupolev strategic bomber and missile carrier from the times of the Soviet Union, still in service as of 2006 and expected to remain in service with the Russian Air Force until at least 2010 [1]. The Bear is...


The first American turboprop was the General-Electric T-31. America skipped over turboprop airliners in favor of the 707, but the technology of the Lockheed Electra would be used in both the long-lived P-3C Orion as well as the classic C-130 Hercules, one of the most successful military aircraft in terms of length of production ever produced. This is a disambiguation page &#8212; a navigational aid which lists other pages that might otherwise share the same title. ... The Lockheed P-3 Orion is a patrol aircraft of the United States military used primarily for anti-submarine warfare. ... The Lockheed C-130 Hercules is a four-engine turboprop cargo aircraft and the main tactical airlifter for military forces worldwide. ...


A European consortium is currently developing the 11,000 shp TP400-D6 turboprop for the Airbus A400M military transport. The engine is all-axial and has a two shaft core, with a free power turbine mounted on a third coaxial shaft. EuroProp International TP400-D6 is the powerplant for the Airbus A400M. When it enters service it will be the most powerful turboprop aircraft in the Western world. ... The Airbus A400M is a four-engine turboprop aircraft, designed by Airbus Military to meet the demand of European nations for military airlift. ...


The most popular turboprop engine ever built is the legendary Pratt & Whitney Canada PT6. The PT6 is a turboprop aircraft engine manufactured by Pratt & Whitney Canada and is the most popular turboprop in history [1]. It has an unusual design in that the air enters from the rear of the engine and the power section is at the front. ...


See also

  • Wikibooks: Jet propulsion

  Results from FactBites:
 
Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal (0 words)
Most of a turboprop engine's power is used to drive a propeller, and the propellers used are very similar to the propellers used in piston or reciprocating engine-driven aircraft (with the exception that turboprops usually use a constant velocity propeller).
Turboprop engines are generally used on small or slow subsonic aircraft, but some aircraft outfitted with turboprops have cruising speeds in excess of 500 kts (926 km/h, 575 mph).
In a turboprop much of the jet thrust is sacrificed in favor of shaftpower, which is obtained by extracting additional power (to that necessary to drive the compressor) from the turbine expansion process.
The Turboprop/Turboshaft Engine (111 words)
A turboprop engine uses thrust to turn a propeller.
A turboshaft is similar to a turboprop engine, differing primarily in the function of the turbine shaft.
Instead of driving a propeller, the turbine shaft is connected to a transmission system that drives helicopter rotor blades; electrical generators, compressors and pumps; and marine propulsion drives for naval vessels, cargo ships, high speed passenger ships, hydrofoils and other vessels.
  More results at FactBites »

 
 

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