The Honeywell/ITEC F124 is a low-bypass

turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which ac ...

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 The McDonnell Douglas (now Boeing) T-45 Goshawk is a highly modified version of the British BAE Systems Hawk land-based training jet aircraft. Manufactured by McDonnell Douglas (now Boeing) and British Aerospace (now BAE Systems), the T-45 i ...

and the

SEPECAT Jaguar The SEPECAT Jaguar is an Anglo-French jet attack aircraft originally used by the British Royal Air Force and the French Air Force in the close air support and nuclear strike role. It is still in service with the Indian Air Force. Originall ...

, and currently powers the Aero L-159 Alca and the

Alenia Aermacchi M-346 The Aermacchi M-346 Master is a family of military twin-engine transonic advanced jet trainers and light combat aircraft. Originally co-developed with Yakovlev as the Yak/AEM-130, the partnership was dissolved in 2000 and then Alenia Aermacchi ...

. The F124 has a rather unusual design for a two spool gas turbine engine, using both

axial Axial may refer to: * one of the anatomical directions describing relationships in an animal body * In geometry: :* a geometric term of location :* an axis of rotation * In chemistry, referring to an axial bond * a type of modal frame, in music * ...

and

centrifugal Centrifugal (a key concept in rotating systems) may refer to: *Centrifugal casting (industrial), Centrifugal casting (silversmithing), and Spin casting (centrifugal rubber mold casting), forms of centrifigual casting *Centrifugal clutch *Centrifug ...

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.

Development

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 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 ev ...

"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 Piaggio & C. SpA (Piaggio ) is an Italian motor vehicle manufacturer, which produces a range of two-wheeled motor vehicles and compact commercial vehicles under seven brands: Piaggio, Vespa, Gilera, Aprilia, Moto Guzzi, Derbi, and Scarabeo. Its ...

. The development would consist of the non-afterburning TFE1042-6 for light attack aircraft/advanced trainer, and TFE1042-7 for the

AMX AMX may refer to: Companies and finance * AMX LLC, a manufacturer of commercial and residential control systems * AMX index (Amsterdam Midkap Index), a stock market index of Euronext Amsterdam * América Móvil (Mexican Stock Exchange ticker symbol ...

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 The General Electric F404 and F412 are a family of afterburning turbofan engines in the class (static thrust). The series is produced by GE Aviation. Partners include Volvo Aero, which builds the RM12 variant. The F404 was developed into the la ...

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. Garrett introduced the TFE742 concept in the early 1990s. Consisting of an uprated core from the TFE1042, the TFE742 was promoted for a twin-engine version of the

BAe 146 The British Aerospace 146 (also BAe 146) is a short-haul and regional airliner that was manufactured in the United Kingdom by British Aerospace, later part of BAE Systems. Production ran from 1983 until 2001. Manufacture by Avro International ...

, the

MPC 75 MPC 75 was an aircraft project of the company "MPC Aircraft GmbH" a subsidiary of "Deutsche Airbus". Work on the project was done mainly between 1988 and 1992 in Hamburg, Germany. Predevelopment work was finished, however the project never got ...

, and other prospective aircraft. Targeting the 70-130 seat passenger aircraft market, the TFE742 was a , high-bypass turbofan driven by a

gearbox Propulsion transmission is the mode of transmitting and controlling propulsion power of a machine. The term ''transmission'' properly refers to the whole drivetrain, including clutch, gearbox, prop shaft (for rear-wheel drive vehicles), differe ...

. In the mid-1990s,

AlliedSignal AlliedSignal was an American aerospace, automotive and engineering company created through the 1985 merger of Allied Corp. and Signal Companies. It subsequently purchased Honeywell for $14.8 billion in 1999, and thereafter adopted the Honeywell n ...

considered developing a

turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. Fuel ...

engine for the European

Future Large Aircraft The Airbus A400M AtlasNamed after the Greek mythological figure. is a European four-engine turboprop military transport aircraft. It was designed by Airbus Military (now Airbus Defence and Space) as a tactical airlifter with strategic capabil ...

military transport (later known as the

Airbus A400M The Airbus A400M AtlasNamed after the Greek mythological figure. is a European four-engine turboprop military transport aircraft. It was designed by Airbus Military (now Airbus Defence and Space) as a tactical airlifter with strategic capabil ...

), which was to be based on the core of the TFE1042. AlliedSignal, AIDC, and other Asian partners also derived an industrial gas turbine from the TFE1042, initially as the AS1042, which evolved into the ASE120.

T-45 Goshawk / BAE Systems Hawk

In the early 1990s, the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

considered the re-engining their fleet of

trainer aircraft with the F124. In 1994, after flight testing a T-45 with the engine, the USN elected not to. The possibility of a F124-powered T-45 arose again in 1996 when

McDonnell Douglas McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it produ ...

offered an F124-engined T-45 to the

Royal Australian Air Force "Through Adversity to the Stars" , colours = , colours_label = , march = , mascot = , anniversaries = RAAF Anniversary Commemoration ...

as a competitor for their trainer requirement.

BAe BAE Systems plc (BAE) is a British multinational arms, security, and aerospace company based in London, England. It is the largest defence contractor in Europe, and ranked the seventh-largest in the world based on applicable 2021 revenues. ...

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 The Rolls-Royce Turbomeca Adour is a two-shaft low bypass turbofan aircraft engine developed by Rolls-Royce Turbomeca Limited, a joint venture between Rolls-Royce (UK) and Turbomeca (France). The engine is named after the Adour, a river in sou ...

(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.

L-159

In 1994, the F124 engine was selected to power the Czech Aero L-159 Alca light combat aircraft. The combination first flew in 1997.

M-346

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 The United Arab Emirates (UAE; ar, اَلْإِمَارَات الْعَرَبِيَة الْمُتَحِدَة ), or simply the Emirates ( ar, الِْإمَارَات ), is a country in Western Asia (The Middle East). It is located at th ...

announced that their M-346 trainers would be powered by the F124-GA-200.

X-45A

The F124 engine powered the Boeing X-45A unmanned combat aerial vehicle demonstrator in the early 2000s.

T-5 Brave Eagle

In 2017 the Aerospace Industrial Development Corporation announced that their AIDC T-5 Brave Eagle would use a variant of the F124.

Possible Jaguar usage

The afterburning F125 engine was being considered, in 2009, by the

Indian Air Force The Indian Air Force (IAF) is the air arm of the Indian Armed Forces. Its complement of personnel and aircraft assets ranks third amongst the air forces of the world. Its primary mission is to secure Indian airspace and to conduct aerial w ...

as a replacement for the

engines in their

aircraft. The new engine would be both lighter and more powerful. It was successfully demonstrated in 2007. This proposal of

to up-engine its fleet of

ground attack aircraft stalled after a decade in August 2019 owing to the high cost involved. Jane's quoted that Honeywell quoted a price of USD2.4 billion for 180 F-125IN turbofan engines as replacements for the Rolls-Royce Turbomeca Adour Mk 811 powerpacks originally installed in the Jaguars.

Design

The F124 engine is a low-bypass, two-spool engine (meaning that there are two rotating shafts, a high-pressure shaft and a low-pressure shaft). The fan/low-pressure compressor has three stages with titanium blades. The first stage has 30 blades, and the overall pressure ratio for the three-stage fan 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. The high-pressure compressor (HPC) has an uncommon arrangement for a small turbofan engine, with both

and a

stages on the same shaft. There are four axial stages and a fifth centrifugal stage. All the blades and the impeller are made from titanium. The fuel is burned in an annular combustor and the core flow passes through a single-stage high-pressure turbine (HPT) followed by a single-stage low-pressure turbine. The HPT is air-cooled. The bypass air from the fan and the exhaust from the core are mixed before exiting through a common nozzle. In the F125 variant of the engine, the mixed flow passes through the afterburner section. The F124 does not have an afterburner.

Variants

;F124-GA-100 *This is the original variant of the engine. It powered the Boeing X-45 demonstrator. ;F124-GA-200 *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

, as well as other small upgrades.ITEC TFE1042-70. ''Jane's Aero Engines''. Last Updated 30 Apr 2009. Accessed 22 Dec 2009. This variant is used in the

Aermacchi M-346 The Aermacchi M-346 Master is a family of military twin-engine transonic advanced jet trainers and light combat aircraft. Originally co-developed with Yakovlev as the Yak/AEM-130, the partnership was dissolved in 2000 and then Alenia Aermacchi ...

.Dubai 09: UAE selects Honeywell's F124 engines for M-346 fleet (2009)
Flight Global
16 Nov 2009. Accessed 22 Dec 2009. ;F124-GA-400 *Variation of the F124-GA-100, modified for the

and the BAE Hawk. The engine was flight tested in the T-45, but the

decided not to re-engine the aircraft with this engine. ;F125-GA-100 *Also known as the TFE1042-70. This is the basic afterburning variant of the engine. 325 produced for the AIDC F-CK-1 Ching-kuo program. ;F125X *Proposed advanced variant of the F125 engine, with a maximum thrust of 12,500 lbf (56 kN).ITEC ready to start F125X turbofan
. ''Flight International''. 8 Apr 1992, p. 13. Accessed 23 Dec 2009. ;F125XX *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.

Applications

;F124 * Aero L-159 Alca * AIDC T-5 Brave Eagle *

Alenia Aermacchi M-346 Master The Aermacchi M-346 Master is a family of military twin-engine transonic advanced jet trainers and light combat aircraft. Originally co-developed with Yakovlev as the Yak/AEM-130, the partnership was dissolved in 2000 and then Alenia Aermacchi ...

* Boeing X-45 ;F125 * AIDC F-CK-1 Ching-kuo