Ishikawajima-Harima began developing a small turbofan engine in the late 1970s as a competitor for the new jet trainer aircraft being developed by
Kawasaki Heavy Industries. The developmental engine was named the XF3, and it was selected over the
SNECMA Turbomeca Larzac in 1982 to power the
XT-4 trainer. The early developmental models of the engine produced of
thrust, but later models (including the model selected for the XT-4) produced of thrust. The production engine was designated the F3-30 (alternatively, the F3-IHI-30), and it first flew in the XT-4 aircraft in 1985. Production of the qualified engine also began in 1985. After the engine and aircraft were in production there were several incidents where one or two of the high pressure
turbine blades failed, forcing the aircraft to make emergency landings. An investigation revealed that the turbine section was suffering from a vibration
resonance problem, leading to the turbine blade failures. The blades were strengthened and modified to dampen the vibrations. The engine, and the aircraft, returned to service in 1990. Beginning in 1999, IHI began upgrading the fielded engines with a new high-pressure turbine to increase their service life. This variant of the engine was known as the
F3-IHI-30B. In 2003, IHI began updating the engine with a more advanced
FADEC. This updated engine was designated the
F3-IHI-30C. Work on this engine began in earnest in 1986, and a demonstrator engine was built and tested in 1987. IHI was formally awarded a contract for the engine in 1992, after spending the previous years developing and testing the engine internally.
Design The F3 is a two-shaft (or two spool) low-bypass
turbofan. It features a two-stage fan (low-pressure compressor) on the low-pressure shaft, followed by a five-stage high-pressure compressor on the high-pressure shaft. The engine uses an
annular combustor, which feeds a single-stage high-pressure turbine followed by a single-stage low-pressure turbine. The XF3-400 variant includes an afterburner after the low-pressure turbine, the production F3 does not. The two-stage fan uses wide chord blades, and both the production F3 and the advanced XF3-400 use the same fan. Unlike the fan, the five-stage compressor differs between the F3 and the XF3-400, with the advanced XF3-400 benefiting from 3D
computational fluid dynamics (CFD) improvements. The high-pressure turbine blades are
single-crystal blades, and they are cooled by a thin film of air from inside of the blades. The low-pressure turbine blades, like the high-pressure compressor, were improved between the F3 and the XF3-400 using 3D CFD. Both the F3 and the XF3-400 use a FADEC for engine control. ==Variants==