| PW1120 | |
|---|---|
 | |
| Type | Turbojet |
| National origin | United States |
| Manufacturer | Pratt & Whitney |
| First run | 1980s |
| Major applications | IAI Lavi |
| Developed from | Pratt & Whitney F100 |
The Pratt & Whitney PW1120 turbojet is a derivative of the F100 turbofan. It was installed as a modification to a single F-4E fighter jet, and powered the canceled IAI Lavi.
The development of the PW1120, according to Israeli Air Force (IDF/AF) specifications, started in June 1980. It retained the F100 core module, gearbox, fuel pump, forward ducts, as well as the F100 digital electronic control, with only minor modifications. Unique PW1120 components included a wide chord low pressure (LP) compressor, single-stage uncooled low pressure (LP) turbine, simplified single stream augmentor, and a lightweight convergent/divergent nozzle. Full scale testing was initiated in June 1982, and flight clearance of the PW1120 was tested in August 1984. The PW1120 had 70 percent similarity with the F100, so the IDF/AF would not need a special facility for spare parts. It would be built under licence by Bet-Shemesh Engines Limited in Israel.
IAI installed one PW1120 in the starboard nacelle of an F-4E-32-MC of the IDF/AF (Number 334/66-0327) to explore the airframe/powerplant combination for an upgrade program of the F-4E, known as Kurnass 2000 ("Heavy Hammer") or Super Phantom and to act as an engine testbed for the Lavi. The powerplant was more powerful, and more fuel efficient than the General Electric J79-GE-17 turbojet normally installed in the F-4E. The structural changes included modifying the air inlet ducts, new powerplant attachment points, new or modified powerplant baydoors, new airframe mounted gearbox with integrated drive generators and automatic throttle system. It also included a modified bleed management and air-conditioning ducting system, modified fuel and hydraulic systems, and a powerplant control/airframe interface. It was first flown on 30 July 1986.
Two PW1120 powerplants were installed in the same F-4E and it was flown for the first time on 24 April 1987. This proved very successful, allowing the Kurnass 2000 to exceed Mach 1 without the afterburners, and endowing a combat thrust-to-weight ratio of 1.04 (17 per cent better than the F-4E). This improved the sustained turn rate by 15 per cent, the climb rate by 36 per cent, medium-level acceleration by 27 per cent and low-level speed with 18 bombs from 1,046 km/h to 1,120 km/h (654 - 700 mph or 565 kn to 605 kn). It was demonstrated at the Paris Air Show in 1987.
Related development
Related lists
The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a combination of the preceding generation engine technology of the turbojet, and a reference to the additional fan stage added. It consists of a gas turbine engine which achieves mechanical energy from combustion, and a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust.
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 afterburner is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat. The afterburning process injects additional fuel into a combustor in the jet pipe behind the turbine, "reheating" the exhaust gas. Afterburning significantly increases thrust as an alternative to using a bigger engine with its attendant weight penalty, but at the cost of increased fuel consumption which limits its use to short periods. This aircraft application of "reheat" contrasts with the meaning and implementation of "reheat" applicable to gas turbines driving electrical generators and which reduces fuel consumption.
The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core.
The General Electric F110 is an afterburning turbofan jet engine produced by GE Aerospace. It was derived from the General Electric F101 as an alternative engine to the Pratt & Whitney F100 for powering tactical fighter aircraft, with the F-16C Fighting Falcon and F-14A+/B Tomcat being the initial platforms; the F110 would eventually power new F-15 Eagle variants as well. The engine is also built by IHI Corporation in Japan, TUSAŞ Engine Industries (TEI) in Turkey, and Samsung Techwin in South Korea as part of licensing agreements.
The Pratt & Whitney F119, company designation PW5000, is an afterburning turbofan engine developed by Pratt & Whitney for the Advanced Tactical Fighter (ATF) program, which resulted in the Lockheed Martin F-22 Raptor. The engine delivers thrust in the 35,000 lbf (156 kN) class and was designed for sustained supersonic flight without afterburners, or supercruise. Delivering almost 22% more thrust with 40% fewer parts than its F100 predecessor, the F119 allows the F-22 to achieve supercruise speeds of up to Mach 1.8. The F119's nozzles incorporate thrust vectoring that enable them to direct the engine thrust ±20° in the pitch axis to give the F-22 enhanced maneuverability.
The Pratt & Whitney J58 is an American jet engine that powered the Lockheed A-12, and subsequently the YF-12 and the SR-71 aircraft. It was an afterburning turbojet engine with a unique compressor bleed to the afterburner that gave increased thrust at high speeds. Because of the wide speed range of the aircraft, the engine needed two modes of operation to take it from stationary on the ground to 2,000 mph (3,200 km/h) at altitude. It was a conventional afterburning turbojet for take-off and acceleration to Mach 2 and then used permanent compressor bleed to the afterburner above Mach 2. The way the engine worked at cruise led it to be described as "acting like a turboramjet". It has also been described as a turboramjet based on incorrect statements describing the turbomachinery as being completely bypassed.
The Pratt & Whitney TF30 is a military low-bypass turbofan engine originally designed by Pratt & Whitney for the subsonic F6D Missileer fleet defense fighter, but this project was cancelled. It was later adapted with an afterburner for supersonic designs, and in this form it was the world's first production afterburning turbofan, going on to power the F-111 and the F-14A Tomcat, as well as being used in early versions of the A-7 Corsair II without an afterburner. First flight of the TF30 was in 1964 and production continued until 1986.
The Pratt & Whitney F100 is an afterburning turbofan engine designed and manufactured by Pratt & Whitney to power the U.S. Air Force's "FX" initiated in 1965, which became the F-15 Eagle. The engine was to be developed in tandem with the F401 which shares a similar core but with the fan upscaled for the U.S. Navy's F-14 Tomcat, although the F401 was later abandoned due to costs and reliability issues. The F100 would also power the F-16 Fighting Falcon for the Air Force's Lightweight Fighter (LWF) program.
The Pratt & Whitney J57 is an axial-flow turbojet engine developed by Pratt & Whitney in the early 1950s. The J57 was the first 10,000 lbf (45 kN) thrust class engine in the United States. The J57/JT3C was developed into the J52 turbojet, the J75/JT4A turbojet, the JT3D/TF33 turbofan, and the XT57 turboprop. The J57 and JT3C saw extensive use on fighter jets, jetliners, and bombers for many decades.
The General Electric J79 is an axial-flow turbojet engine built for use in a variety of fighter and bomber aircraft and a supersonic cruise missile. The J79 was produced by General Electric Aircraft Engines in the United States, and under license by several other companies worldwide. Among its major uses was the Lockheed F-104 Starfighter, Convair B-58 Hustler, McDonnell Douglas F-4 Phantom II, North American A-5 Vigilante and IAI Kfir.
The Pratt & Whitney J52 is an axial-flow dual-spool turbojet engine originally designed for the United States Navy, in the 40 kN class. It powered the A-6 Intruder and the AGM-28 Hound Dog cruise missile. As of 2021 the engine was still in use in models of the A-4 Skyhawk.
The General Electric F404 and F412 are a family of afterburning turbofan engines in the 10,500–19,000 lbf (47–85 kN) class. The series is produced by GE Aerospace. Partners include Volvo Aero, which builds the RM12 variant. The F404 was developed into the larger F414 turbofan, as well as the experimental GE36 civil propfan.
Reaktionsmotor 12 (RM12) is a low-bypass afterburning turbofan jet engine developed for the Saab JAS 39 Gripen fighter. A version of the General Electric F404, the RM12 was produced by Volvo Aero. The last of the 254 engines was produced on 24 May 2011, at which time it had reached 160,000 flight hours without any serious incidents.
A jet engine performs by converting fuel into thrust. How well it performs is an indication of what proportion of its fuel goes to waste. It transfers heat from burning fuel to air passing through the engine. In doing so it produces thrust work when propelling a vehicle but a lot of the fuel is wasted and only appears as heat. Propulsion engineers aim to minimize the degradation of fuel energy into unusable thermal energy. Increased emphasis on performance improvements for commercial airliners came in the 1970s from the rising cost of fuel.
The Westinghouse J40 was an early high-performance afterburning turbojet engine designed by Westinghouse Aviation Gas Turbine Division starting in 1946 to a US Navy Bureau of Aeronautics (BuAer) request. BuAer intended to use the design in several fighter aircraft and a bomber. However, while an early low-power design was successful, attempts to scale it up to its full design power failed, and the design was finally abandoned, deemed a "fiasco" and a "flop".
The Volvo RM8 is a low-bypass afterburning turbofan jet engine developed for the Saab 37 Viggen fighter. An augmented bypass engine was required to give both better fuel consumption at cruise speeds and higher thrust boosting for its short take-off requirement than would be possible using a turbojet. In 1962, the civil Pratt & Whitney JT8D engine, as used for airliners such as the Boeing 727, was chosen as the only engine available which could be modified to meet the Viggen requirements. The RM8 was a licensed-built version of the JT8D, but extensively modified for supersonic speeds, with a Swedish-designed afterburner, and was produced by Svenska Flygmotor.
The familiar study of jet aircraft treats jet thrust with a "black box" description which only looks at what goes into the jet engine, air and fuel, and what comes out, exhaust gas and an unbalanced force. This force, called thrust, is the sum of the momentum difference between entry and exit and any unbalanced pressure force between entry and exit, as explained in "Thrust calculation".
The Pratt & Whitney F401 was an afterburning turbofan engine developed by Pratt & Whitney in tandem with the company's F100. The F401 was intended to power the Grumman F-14 Tomcat and Rockwell XFV-12, but the engine was canceled due to costs and development issues.