Over four decades, the F404 developed and produced at GE’s Lynn, Massachusetts, plant has powered thousands of F/A-18 Hornets for the U.S. Navy and other Allied nations, as well as other aircraft applications, most notably the U.S. Air Force (USAF) F-117 Stealth Fighter.
Earlier this year, the Navy took its last operational F404-powered F/A-18C Hornet out of service. This completes the Navy’s transition to the newer F/A-18 Super Hornet, powered by GE’s F414 successor engine.
However, the F404 engine continues to power more than 250 F/A-18 Hornets with the U.S. Marines and with U.S. Allies around the world. Also, it is being modernized for new aircraft, including the USAF T-X trainer and Korea’s T-50 aircraft. “There’s lots of runway ahead for the F404,” says Dan Meador, GE Aviation’s senior account manager for U.S. Navy and Marine Programs in Washington, D.C.
Remarkably, the F404 and its successor engines have been selected to power 20 aircraft applications since the late 1970s.
Often called the “ubiquitous fighter engine,” the F404 is one of the great GE Aviation success stories—an engine born and popularized through a company commitment to an affordable, lightweight fighter jet design. Put an emphasis on affordable.
The F404 launch came at a critical juncture for GE Aviation’s fighter engine enterprise, which struggled in the mid-1970s. Between 1970 and 1975, the U.S. government selected rival Pratt & Whitney to provide the exclusive jet power for the new USAF twin-engine F-15 and single-engine F-16 fighters, as well as the Navy twin-engine F-14. That trend began to reverse itself with the arrival of the F404.
The F404’s genesis dates to 1969 when the Lynn team launched the GE15 development engine for lightweight fighters being studied by the U.S. and abroad. An outgrowth of the GE1 building block technology program of the early 1960s, the GE15 was a dual-shaft, low-bypass turbofan with an efficient compressor and simple mechanical structure in the 14,000-pound thrust class.
At the time, Northrop was pursuing jet designs to replace its popular F-5 fighter, a small, low-cost aircraft sold since the early 1960s to U.S. Allies worldwide. GE’s rugged J85 turbojet powered that aircraft, so Northrop naturally looked to GE to create an engine for the F-5 successor. The GE15 design supported Northrop’s design efforts and evolved into what GE designated the J101 fighter engine.
In 1972, the plot thickened when the USAF awarded GE with a life-saving $10 million contract to further define the mostly self-funded J101 design for smaller fighter jets, including Northrop’s YF-17 lightweight fighter prototype. At the time, GE leaders, including GE Vice Chairman Jack Parker and the aviation division’s leader, Gerhard Neumann, viewed the J101 engine as filling a jet-power thrust void in the U.S. military arsenal between GE’s J85 and P&W’s new F100 fighter engine for the F-15.
GE called the J101 design a “continuous bleed” or “leaky” engine because continuous flow of air from the fan cooled the afterburner and nozzle downstream. This clever design feature allowed the engine to operate at higher temperatures and pressures, but with less installed drag. The combustor was based on the design of the new CF6 commercial engine. Also, advanced film-cooling technology in the afterburner enabled GE to increase turbine inlet temperatures. In the parlance of the times, it was a compact, hot-rod engine.
That same year, General Dynamics and Northrop received separate USAF contracts to create fighter prototypes for the “Light-Weight Fighter” (LWF) competition being conducted by the U.S. Department of Defense. For the competition, GE and Northrop teamed on the J101-powered YF-17 prototype fighter jet against General Dynamics and P&W with their F100-powered YF-16 prototype.
The big decision came down in 1975: The USAF selected the P&W F100-powered, single-engine YF-16 over the GE J101-powered YF-17 for the LWF program. The U.S. government envisioned this winning aircraft in both USAF and Navy fleets.
Was GE shut out from yet another fighter aircraft program? Not so fast. The Navy had reservations about deploying the YF-16 (later designated the F-16) for carrier service with its single engine and narrow landing gear. Instead, the Navy selected the twin-engine YF-17 prototype.
GE had its opening. The J101 engine, modified for higher thrust, evolved into the F404 engine. The YF-17, redesigned for carrier requirements, became the F/A-18 Hornet. With one change: McDonnell Douglas became the aircraft contractor and Northrop the prime subcontractor.
The Lynn team’s focus on affordability arguably led to the engine’s most significant attribute. The year before, defense officials had disclosed to the aviation press that two J101s cost less than one F100 powering the F-16. The F404 was based on the J101 core but with a larger fan for increased airflow and a larger nozzle. The increased airflow boosted F404 thrust to 16,000 pounds to make the F/A-18 more maneuverable.
GE committed to 30 percent lower maintenance costs for the F404-powered F/A-18 compared to the Navy’s GE J79-powered F-4s. Also, F404 had 40 percent fewer parts and half the weight of the J79 engine while generating similar thrust. In all, the F404 represented a significant technology advance for the military fighter sector. One of the most successful fighter engine/aircraft combinations in military aviation history was off the ground.
By the time the Navy took delivery of the first F404-powered F/A-18 in 1978, the engine had already demonstrated significant capability in a very attractive thrust class for several other applications. In 1981, as the F/A-18 became an integral part of the Navy fleet, the USAF secretly selected a non-afterburning F404 variant for the F-117 Stealth Fighter, an aircraft unknown to the public for several more years.
By the early 1990s, the F/A-18 Hornet began to give way to the Navy’s larger and more capable F/A-18 Super Hornet, powered by the successful GE F414 engine. Today, more than 1,650 F414s are powering Super Hornets. And, like the F404, the successor engine is winning new aircraft applications, such as Sweden’s Saab JAS 39 Gripen and India’s HAL Tejas Light Combat Aircraft.
Meanwhile, the F404 continues to evolve with new aircraft applications. “Today’s F404 is not your daddy’s F404,” Meador says. “For example, the United States Air Force’s next generation training aircraft, the T-X, will be powered by a single F404-102 that will include a FADEC [full authority digital electronic control] and other new technologies.”
One of military aviation’s great fighter jet engines will be with us for many more decades.