|F124 / F125|
|Honeywell F124 cutaway|
|National origin||United States / |
Taiwan (Republic of China)
|Manufacturer||International Turbine Engine Corporation / |
|First run||1979 |
|Major applications||Aermacchi M-346 |
Aero L-159 Alca
AIDC F-CK-1 Ching-kuo
|Number built||460 (by 2004) |
|Unit cost||Est. $2.5 million USD (2005 dollars).|
|Developed from||Honeywell TFE731|
The Honeywell/ITEC F124 is a low-bypass turbofan engine derived from the civilian Honeywell TFE731. The F125 is an afterburning version of the engine. The engine began development in the late 1970s for the Republic of China (Taiwan) Air Force AIDC F-CK Indigenous Defence Fighter (IDF), and it first ran in 1979. The F124/F125 engine has since been proposed for use on other aircraft, such as the T-45 Goshawk and the SEPECAT Jaguar, and currently powers the Aero L-159 Alca and the Alenia Aermacchi M-346. The F124 has a rather unusual design for a two spool gas turbine engine, using both axial and centrifugal compressors in its high-pressure compressor. There are currently only three production variants of the engine, although several more have been proposed throughout its lifespan.
In 1978, Garrett announced joint research on the TFE1042 afterburner with Swedish company Volvo Flygmotor AB in order to provide an engine for the AIDC F-CK Indigenous Defence Fighter (IDF) being developed for the Republic of China (Taiwan) Air Force (ROCAF). The TFE731 Model 1042 was touted as a low bypass ratio "military derivative of the proven commercial TFE731 engine" and "provides efficient, reliable, cost effective propulsion for the next generation of light strike and advanced trainer aircraft", with thrust of 4260 lbf (18.9 kN) dry and 6790 lbf (30.2 kN) with afterburner. After initial negotiation, the investment was going to be divided between Garrett, Volvo, AIDC, and Italian company Piaggio. The development would consist of the non-afterburning TFE1042-6 for light attack aircraft/advanced trainer, and TFE1042-7 for the AMX or F-5 upgrade. Garrett would be responsible for the core engine, and Volvo would be responsible for the fan section and the afterburner. The engine first ran for 3 hours at a Volvo test facility in 1979.
AIDC also suggested upgrading TFE1042-7 to 8000 lbf (31 to 36 kN) thrust as twin engine solution, in order to compete with General Electric F404 for applications such as the JAS 39 Gripen. However, the Gripen project decided to continue with a single engine F404 variant, built by Volvo, and Volvo left the project to at that point to focus on the Gripen work. Piaggio asked to participate at a later date due to financial reasons and left the program as well. Thus only Garrett and AIDC invested in the new International Turbine Engine Corporation (ITEC), with the contract signed in 1982.
In 1988, ITEC decided to invest in the 12,000 lb TFE1088-12, which was re-designated as TFE1042-70A (for political reason as well). Preliminary study had shown that IDF could supercruise with the new engine. At the same time, GE decided to enter the market with J101/SF, a smaller version of F404. However, after the IDF order was cut in half due to budget concerns, the TFE1088-12 engine upgrade plan ended as well. The F-CK IDF first flew in 1989, and aircraft were delivered through 1999.
- T-45 Goshawk / BAE Systems Hawk
In the early 1990s, the United States Navy considered the re-engining their fleet of T-45 Goshawk trainer aircraft with the F124. In 1994, after flight testing a T-45 with the engine, the USN elected not to do that.
The possibility of a F124-powered T-45 arose again in 1996 when McDonnell Douglas offered an F124-engined T-45 to the Royal Australian Air Force as a competitor for their trainer requirement. BAe wanted to offer the F124 as an option on their entry for the RAAF trainer requirement, the BAE Hawk (which the T-45 is based on), but ITEC refused to give BAe permission to offer it. ITEC's decision turned out to be a mistake, as the RAAF select the Hawk as their trainer. However, after the selection of the aircraft, the RAAF decided to have a separate competition between the F124 and the Rolls-Royce Turbomeca Adour (which was BAe's selection) to power the new trainers. In 1997 the RAAF elected to use the Adour engine, effectively ending the F124's chances of being used on Hawk or T-45 aircraft.
In 2000, Alenia Aermacchi announced that their new M-346 trainer/light attack aircraft would be powered by the F124 engine, choosing it over its common rival, the Adour. In 2009, the United Arab Emirates announced that their M-346 trainers would be powered by the F124-GA-200.
- Possible Future Uses
The afterburning F125 engine is being considered, as of 2009, by the Indian Air Force as a replacement for the Rolls-Royce Turbomeca Adour engines in their SEPECAT Jaguar aircraft. The new engine would be both lighter and more powerful. It was successfully demonstrated in 2007.
The F124 engine is fundamentally a low bypass, two spool engine (meaning that there are two rotational shafts, a high-pressure shaft and a low-pressure shaft). The fan/low-pressure compressor section is made of three stages with titanium blades. The first stage has 30 un-shrouded blades, and the overall pressure ratio for the three stage fan section is 2.5:1. Some of the air is bypassed (Bypass ratio of 0.472:1), and the rest is fed to the high-pressure compressor section.
The high-pressure compressor (HPC) of the F124 is a fairly unusual design among turbofan engines; it employs both axial and a centrifugal compressors in a single design. There are four axial stages that lead to a fifth centrifugal stage. All the blades and the impeller are made from titanium.
The compressed air is combusted in an annular combustor and then exhausted to a single-stage high-pressure turbine (HPT) followed by a single-stage low-pressure turbine. The HPT is air-cooled. The exhaust is mixed, meaning the bypass air from the fan and the exhaust from the core exit through a common nozzle. In the F125 variant of the engine, the exhaust passes through the afterburner section. The F124 does not have an afterburner.
- This is the original variant of the engine. It powered the Boeing X-45 demonstrator.
- Slightly de-rated variant of the F124-GA-100; the maximum thrust is 6250 lbf (27.80 kN) and the engine weighs 28 lb (13 kg) less. This variant utilizes an all new accessory gearbox, as well as other small upgrades. This variant is used in the Aermacchi M-346.
- Variation of the F124-GA-100, modified for the T-45 Goshawk and the BAE Hawk. The engine was flight tested in the T-45, but the United States Navy decided not to re-engine the aircraft with this engine.
- Also known as the TFE1042-70. This is the basic afterburning variant of the engine. Used in the AIDC F-CK-1 Ching-kuo.
- Proposed advanced variant of the F125 engine, with a maximum thrust of 12,500 lbf (56 kN).
- Further advanced variant of the F125 engine, this one producing 16,400 lbf (73 kN) of thrust. If it were built, there would have been a related F124XX non-afterburning variant, producing 10,800 lbf (48 kN) of thrust.
- Type: Turbofan
- Length: 102.1 in (259 cm)
- Diameter: 36 in (91.4 cm)
- Dry weight: 1050 lb (521.6 kg)
- Compressor: 3 axial fan (low pressure compressor) stages, 4 axial high pressure compressor stages, 1 centrifugal high pressure compressor stage
- Turbine: 1 stage high pressure turbine, 1 stage low pressure turbine
- Maximum thrust: 6280 lbf (28 kN)
- Overall pressure ratio: 19.4:1
- Bypass ratio: 0.49:1
- Specific fuel consumption: 0.78 lb/lbf-hr (82.6 kg/kN-hr)
- Thrust-to-weight ratio: 5.3:1
- Honeywell F124 (TFE1042). Forecast International[permanent dead link]. Archived Jul 2005. Accessed 22 Dec 2009.
- Hua, Hsi-Chun (1997). Story of Yun Han (in Chinese). China Productivity Center.
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- Norris, Guy (1996). "ITEC turns down BAe on RAAF". Flight International. 3 Apr 1996, p. 5. Accessed 23 Dec 2009.
- "BAe's Hawk trainer chosen for RAAF's lead-in fighter project", Flight International. 20 Nov 1996, p. 22. Accessed 23 Dec 2009.
- Lewis, Paul and Phelan, Paul (1997). "RAAF stays with Adour on Hawk". Flight International. 5 Mar 1997, p. 14. Accessed 23 Dec 2009.
- "F124 engine turns Yak-130 into the Aermacchi 346". Flight International. 25 Jul 2000, p. 8. Accessed 23 Dec 2009.
- Govindasamy, Siva (2009). "Dubai 09: UAE selects Honeywell's F124 engines for M-346 fleet". Flight Daily News. 16 Nov 2009. Accessed 23 Dec 2009.
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- Grevatt, Jon. "Taiwan starts production of XAT-5 prototype". janes.com. Janes. Retrieved 8 May 2019.
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- F124. Honeywell F-124 page Archived 2015-01-08 at the Wayback Machine. Accessed 22 Dec 2009.
- Dubai 09: UAE selects Honeywell's F124 engines for M-346 fleet (2009). Flight Global. 16 Nov 2009. Accessed 22 Dec 2009.
- "ITEC ready to start F125X turbofan". Flight International. 8 Apr 1992, p. 13. Accessed 23 Dec 2009.
- Gas Turbine Engines. Aviation Week & Space Technology Source Book 2009. p. 119.
- Ching-Kuo (IDF) page on airforce-technology.com[unreliable source?]
- Honeywell Tests First Production Configuration F124-GA-200