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Encyclopedia > Propfan
General Electric GE-36 UDF Unducted Fan engine on a McDonnell Douglas MD-81 testbed
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General Electric GE-36 UDF Unducted Fan engine on a McDonnell Douglas MD-81 testbed

A propfan is a modified turbofan engine, with the fan placed outside of the engine nacelle on the same axis as the compressor blades. Propfans are also known as ultra-high by-pass (UHB) engines. The design is intended to offer the speed and performance of a turbofan, with the fuel economy of a turboprop. A General Electric GE-36 unducted fan engine at London-Farnborough Airshow, September, 1988. ... A General Electric GE-36 unducted fan engine at London-Farnborough Airshow, September, 1988. ... The General Electric GE-36 engine was an experimental turbojet engine that was a hybrid between turbojet and turboprop aircraft engines, known as an Unducted Fan or Propfan. ... DC-10, retired from American Airlines fleet at gate McDonnell Douglas was a major American aerospace manufacturer, producing a number of famous commercial and military aircraft. ... The Douglas DC-9 is a twin-engined jet airliner, first manufactured in 1965 and, in much modified form and under a succession of different names, still in production today as the Boeing 717. ... CFM56-3 turbofan, lower half, side view. ... In airplanes, the nacelle is a covered housing separated from the main structure that usually holds engines, fuel, or equipment. ... 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 schematic diagram showing the operation of a turboprop engine. ...


Turboprops have a fairly strict sweet spot at speeds below about 450 mph. The reason is that all propellers lose efficiency at high speed, due to an effect known as wave drag that occurs just below supersonic speeds. This powerful form of drag has a sudden onset, and led to the concept of a sound barrier when it was first encountered in the 1940s. In the case of a propeller this effect can happen any time the prop is spun fast enough that the tips of the prop start travelling near the speed of sound, even if the plane is sitting still. A sweet spot is a place, often numerical as opposed to physical, where a combination of factors suggest a particularly suitable solution. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Wave drag is an aerodynamics term that refers to a sudden and very powerful form of drag that appears on aircraft flying at high-subsonic speeds. ... This page is about high speed motion of bodies such as airplanes through air or other fluids. ... For a solid object moving through a fluid or gas, drag is the sum of all the aerodynamic or hydrodynamic forces in the direction of the external fluid flow. ... U.S. Navy F/A-18 at transonic speed. ...


This can be controlled to some degree by adding more blades to the prop, using up more power at a lower rotational speed. This is why most WWII fighters started with two-blade props and were using five-blade designs by the end of the war. The only downside to this approach is that adding blades makes the propeller harder to balance and maintain. At some point though the forward speed of the plane combined with the rotational speed of the propeller will once again result in wave drag problems. For most aircraft this will occur at speeds over about 450 mph. Combatants Allied Powers Axis Powers Commanders {{{commander1}}} {{{commander2}}} Strength {{{strength1}}} {{{strength2}}} Casualties 17 million military deaths 8 million military deaths {{{notes}}} World War II, also known as the Second World War, was a military conflict that took place between 1939 and 1945. ...

Swept propeller

A method of decreasing wave drag was discovered by German researchers in WWII: sweeping the wing backwards. Today almost all aircraft designed to fly much above 450 mph (700 km/h) use a swept wing. In the 1970s, NASA started researching propellers with similar sweep. Since the inside of the prop is moving more slowly than the outside, the blade became progressively more swept toward the outside, leading to a curved shape similar to a scimitar. Image File history File links Example of swept propeller shape. ... The swept wing of an airliner: British Midland Airbus A320-200 A swept-wing is a wing planform used on high-speed aircraft that spend a considerable portion of their flight time in the transonic. ... NASA logo Listen to this article · (info) This audio file was created from an article revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... A scimitar with a large blade (kilij) This article refers to the scimitar sword. ...

Progress propfan on the Antonov An-70.
Progress propfan on the Antonov An-70.

The propfan concept was intended to deliver 35% better fuel efficiency than contemporary turbofans, and in this they succeeded. In static and air tests on a modified DC-9, propfans reached a 30% improvement. This efficiency comes at a price, as one of the major problems with the propfan is noise, particularly in an era where aircraft are required to comply with increasingly strict Stage III and Stage IV noise requirements. Image File history File links Download high resolution version (892x607, 87 KB) Antonow An-70 engine detail, photo taken bei rvb, provided by user:jno ZMKB Progress D-27 Propfan File links The following pages link to this file: Propfan ... Image File history File links Download high resolution version (892x607, 87 KB) Antonow An-70 engine detail, photo taken bei rvb, provided by user:jno ZMKB Progress D-27 Propfan File links The following pages link to this file: Propfan ... The Douglas DC-9 is a twin-engined jet airliner, first manufactured in 1965 and, in much modified form and under a succession of different names, still in production today as the Boeing 717. ...


General Electric's Unducted Fan (UDF) is a variation on NASA's original propfan concept, and appears similar to a pusher configuration piston engine. GE's UDF has a novel direct drive arrangement, where the reduction gearbox is replaced by a low speed 7 stage turbine. The turbine rotors drive one prop, whilst the other prop is connected to the 'unearthed' turbine stators and rotates in the opposite direction. General Electric Aircraft Engines (GEAE) is the top supplier of aircraft engines in the world and offers engines for the majority of commercial aircraft. ... NASA logo Listen to this article · (info) This audio file was created from an article revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... A British WWI-era F.E.2b pusher. ...


Boeing intended to offer GE's pusher UDF engine on the 7J7 platform, and McDonnell Douglas were going to do likewise on their MD-94X airliner. Both airliners were to use rear-fuselage mounted General Electric GE-36 engines. Similar was the Antonov An-180, powered by two rear-mounted Progress D-27 propfans and planned for a 1995 introduction. Another Russian design was the Yak-46. None of the projects came to fruition, mainly because of excessive cabin noise and low fuel prices. The Boeing Company (NYSE: BA)(TYO: 7661 ) is the worlds leading aircraft and aerospace manufacturer, headquartered in Chicago, Illinois, with its largest production facilities in Everett, Washington, about 30 miles north of Seattle, Washington. ... Boeing 7J7 (artists concept) The Boeing 7J7 was a short- to medium-range airliner proposed by Boeing in the 1980s, but never built. ... DC-10, retired from American Airlines fleet at gate McDonnell Douglas was a major American aerospace manufacturer, producing a number of famous commercial and military aircraft. ... The McDonnell Douglas MD-94X was a planned propfan-powered airliner, intended to begin production in 1994. ... An airliner is a large fixed-wing aircraft (an aeroplane/airplane) initially designed for the transport of paying passengers, and usually operated by an airline company (which owns or leases the aircraft). ... In an aircraft, the fuselage is the main body section that holds crew and passengers or cargo. ... The General Electric GE-36 engine was an experimental turbojet engine that was a hybrid between turbojet and turboprop aircraft engines, known as an Unducted Fan or Propfan. ...


During the 1990s, Antonov also developed the An-70, powered by four Progress D-27s in a tractor configuration; the Russian Air Force placed an order for 164 aircraft in 2003. The 1990s decade refers to the years from 1990 to 1999, inclusive, the last decade of the 20th Century. ... Private Antonov AN-2 in the UK Antonov, aka Antonov Aeronautical Scientific/Technical Complex (Antonov ASTC) (Ukrainian: ) is a Ukraine-based (since 1952) aircraft manufacturing and services company (design office prefix An) with particular expertise in the field of very large aircraft construction. ... The Antonov An-70 is a four-engined military transport aircraft. ... An aircraft constructed with a tractor configuration has the engine mounted with the propeller facing forwards such that the aircraft is pulled through the air, as opposed to the pusher configuration in which the propeller faces backwards and the aircraft is pushed through the air. ... Soviet Air Force, also known under the abbreviation VVS, transliterated from Russian: ВВС, Военно-воздушные силы (Voenno-Vozdushnye Sily), formed the official designation of the airforce of the Soviet Union. ... This is a list of aviation-related events from 2003: Events February 1The Space Shuttle Columbia disintegrates, killing all seven occupants. ...


Propfan engines

  • General Electric GE-36 UDF
  • Progress D-27


The General Electric GE-36 engine was an experimental turbojet engine that was a hybrid between turbojet and turboprop aircraft engines, known as an Unducted Fan or Propfan. ...

Lists of Aircraft | Aircraft manufacturers | Aircraft engines | Aircraft engine manufacturers This list of aircraft is sorted alphabetically, beginning with the name of the manufacturer (or, in certain cases, designer). ... This is a list of aircraft manufacturers (in alphabetic order). ... List of aircraft engines: // Piston engines Allison V-1710 Alvis Leonides Armstrong-Siddeley Puma Armstrong-Siddeley Cheetah Armstrong-Siddeley Nimbus Bentley BR1 Rotary BMW 801 Bristol Aquila Bristol Centaurus Bristol Hercules Bristol Jupiter Bristol Pegasus Bristol Perseus Bristol Phoenix Bristol Taurus Bristol Titan Bristol Hydra Bristol Mercury Clerget rotary Continental... This is a list of aircraft engine manufacturers both past and present. ...


Airports | Airlines | Air forces | Aircraft weapons | Missiles | Timeline of aviation This is a list of airlines in operation. ... This is a list of Air Forces, sorted alphabetically by country. ... This is a list of aircraft weapons, past and present. ... Below is a list of (links to pages on) missiles, sorted alphabetically by name. ... This is a timeline of aviation history. ...


  Results from FactBites:
 
Propfan turbo-engine (2337 words)
In particular, the relatively large hub ratio of the propfan blades, thus the ratio of the inside diameter of the blade to the outside diameter of the blade, is disadvantageously large, since, for aerodynamic reasons, the working turbine must have a certain minimum diameter.
It is also a disadvantage in the above-noted propfan turbo-engine, that the approach flow conditions of the propfan blades, as a result of the gas turbine body, which is arranged upstream of the propfan blades, during normal flight, are disturbed at least in proximity of the hub of the propfan.
In the present case, i.e., in the case of the contra-rotating propfan with a shroud, the approach flow Mach number is set by the contour of the shroud and the design of the propfan rotors, i.e., it is independent of the flying speed.
Propfan turbine engine - Patent 4887424 (1883 words)
A propfan turbine engine as claimed in claim 1, where said cooling means has an intake channel for cooling air of annular ring-shape arranged in front of the intake channel of the gas turbine relative to the direction of air flow.
A propfan turbine engine as claimed in claim 2 wherein said reduction gearing comprises a gear housing, said gas turbine comprises an intake housing, said gear housing and intake housing defining an annular space which is connected to said intake channel of said cooling means, said heat exchanger being disposed in said annular space.
A nose cap 17 and cowlings 18a, 18b and 18c are fastened to the rotors of the propfan stages 11 and 12.
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