The F110 emerged from an intersection of efforts in the 1970s by General Electric to reenter the U.S. fighter engine market and the U.S. Air Force's desire to address the reliability, longevity, and maintenance issues with the
Pratt & Whitney F100 engines that powered its
F-15s and
F-16s. In 1975, General Electric used its own funds to begin developing the F101X, a derivative of its F101 engine for the
B-1 bomber; the F101X would inherit much of the core design while having a smaller fan that was upscaled from the
F404 so that its thermodynamic cycle and thrust were better suited for a fighter engine. The convergent-divergent iris nozzle was also derived from the F404. The cancellation of the B-1A by the
Carter Administration (in lieu of the Advanced Technology Bomber which became the
B-2) meant a loss of business for General Electric, and provided further impetus to provide the F101X for the fighter engine market. The engine attracted the interest of the Air Force's Engine Model Derivative Program (EMDP), and in 1979 began funding it as the F101 Derivative Fighter Engine, or F101 DFE. The Air Force saw the F101 DFE as a potential alternative to the F100 and also a way to coerce better performance from Pratt & Whitney in addressing issues with the F100. Seeking to drive unit costs down and improve contractor performance, the Air Force implemented the Alternate Fighter Engine (AFE) competition between the F100 and F110 in 1983 in what was nicknamed "The Great Engine War", where the engine contract would be awarded through competition. The Air Force would buy both engines starting in 1984, with contracts being competed every fiscal year and the percentages of F100 versus F110 would vary based on contract; the competitions eventually ended in 1992. The F101 DFE was also tested in the
F-14B prototype in 1981, and the aircraft saw considerable performance improvement over the existing
Pratt & Whitney TF30. Although further testing was halted by the Navy in 1982, it would use the results of the Air Force's AFE evaluation to choose the powerplant for future F-14s. The F101 DFE was eventually chosen by the Navy in 1984 and was designated
F110-GE-400. In contrast to the ambitious raw performance goals for the F100 of high thrust and low weight, the F110 placed a greater emphasis on balancing between reliability, operability, and performance. The fan and inlet guide vanes were designed to smooth airflow to increase resistance to compressor stalls. The engine has an electronic and hydromechanical control system that make it more forgiving of rapid throttle inputs. The main difference between the -100 and the -400 is the latter's augmentor section, being about 50 inches longer. The -100, used on the F-16C/D Block 30/40, had an uninstalled static thrust of in intermediate power and in afterburner; the figures for the -400, used on the F-14B/D, were and respectively.
Further developments In the mid-1980s, the Air Force sought greater power for its tactical fighters and began Improved Performance Engine (IPE) programs for the F100 and F110, with the goal of achieving thrust in the class, while retaining the durability improvements achieved in the F100-220 and F110-100. The result would be the Pratt & Whitney F100-PW-229 and General Electric
F110-GE-129. Compared to the F110-100, the -129 incorporated component improvements, including a full authority digital engine control (
FADEC), that allowed maximum thrust to be achieved in a wider range of conditions and across larger portions of the flight envelope, while retaining 80% commonality; bypass ratio was slightly reduced to 0.76. The -129 produces of thrust in intermediate power and in full afterburner, and was first fielded in 1992 on the F-16C/D Block 50; the engine would also power enhanced F-15E variants, starting with the F-15K for South Korea. A non-afterburning variant of the F110, designated the
F118, would power the B-2 stealth bomber and the re-engined
U-2S reconnaissance aircraft. A variant of the F110-100 fitted with a 3-dimensional axisymmetric
thrust vectoring nozzle, referred by General Electric as the Axisymmetric Vectoring Exhaust Nozzle (AVEN), was tested on a specially modified F-16 called the
NF-16D VISTA under the Multi-Axis Thrust-Vectoring (MATV) program; the nozzle could vector the exhaust up to 17 degrees from the axial line in any direction. The F110 would see the development of a further enhanced variant starting in 2000 with the
F110-GE-132, initially referred to as the F110-GE-129EFE (Enhanced Fighter Engine). Flight tests began in 2003, and the first engine was delivered in 2005. Technology from the -132 as well as from commercial
CFM56 developments have been applied to the F110 Service Life Extension Program (SLEP), and F110-129 upgraded with SLEP technology were given the designation -129C. Further improved subvariants with 6,000-cycle intervals were designated -129D (for the F-16) and -129E (for the F-15). The -129E also powers the
TAI Kaan prototype. ==Major applications==