On April 13, 1972, the U.S. Air Force announced its selection of General Dynamics (YF-16) and Northrop (YF-17) for the Light-Weight Fighter (LWF) program. The Air Force tasked each company with building two prototypes of their unique designs.
Established in early 1972, the LWF program pursued three key objectives: exploring the integration of new technologies, reducing financial risk through a “low-cost” fighter concept, and providing the Department of Defense (DoD) with a viable option to meet operational requirements. The program balanced experimental and practical goals, which explained why the prototypes carried standard Air Force armament: a 20mm Gatling gun and Sidewinder missiles.
The concept of an affordable fighter formed the cornerstone of the LWF program. DoD analyst Pierce M. Sprey introduced this idea in his 1968 “FX2 Study” report (with “FX” already designated for the future F-15 Eagle). Sprey’s analysis revealed that a $32 billion investment over ten years would yield only 1,200 F-4/F-111/F-15 fighters. However, by pursuing a more austere and lighter design, the Air Force could potentially field a force of 4,200 fighters. Initially, the Air Force showed little enthusiasm for the project, viewing the FX2 as an “F-15 killer” since Sprey’s report challenged the acquisition of expensive aircraft. The FX2 concept later evolved into a “hi-low mix” strategy, combining expensive and affordable aircraft. By 1970-71, as the F-15 program gained momentum, the Air Force warmed to the idea of an experimental “low-cost” fighter program that would incorporate new technologies.
Development Of The Yf-16
On April 13, 1972, General Dynamics (Convair Division, later reorganized as Fort Worth Division) secured a $37.9 million contract to develop and build two YF-16 prototypes. The US Air Force provided flexible specifications, giving manufacturers considerable latitude in their design approaches. This freedom became evident in the distinct solutions presented by General Dynamics and Northrop in the Light Weight Fighter (LWF) program, with Northrop’s YF-17 evolving from their in-house P.530 “Cobra” project.
General Dynamics had explored the concept of a cost-effective light fighter since 1971. While the company had faced challenges with the F-111 program, these experiences sharpened their focus on finding optimal solutions. Rather than viewing the F-111 setbacks as a liability, they demonstrated General Dynamics’ enhanced awareness of potential pitfalls and their determination to avoid them. The Texas-based company recognized the Air Force’s growing interest in lighter, more affordable fighters, as indicated in the “FX2 Study.” This alignment of vision contributed to the YF-16’s rapid development – the team completed the project in just 21 months, compared to Northrop’s 25-month timeline for the YF-17. The first YF-16 rolled out of the factory on December 13, 1973.
A Smart Plane
The YF-16 emerged as a compact, single-engine fighter incorporating numerous technological advances developed in NASA laboratories and tested on Air Force aircraft. Key innovations included:
- Vortex/apex surface control, featuring razor-sharp leading edges and streamlined wing-fuselage junctions with pronounced sweep
- “Lifting body” design that enhanced fuselage lift at high angles of attack through mechanical and aerodynamic means
- “Fly-by-wire” electronic flight control system that provided faster response times
- Configuration Sensitive Stability Control (CSS) for improved lateral stability across all flight conditions
- Variable Wing Camber with automated leading-edge slats programmed according to speed and angle of attack
The aircraft also introduced pilot-friendly features that earned praise from test pilots: a side-stick controller replacing the traditional center-mounted stick, a reclinable seat adjusting from 13Β° to 30Β° based on G-forces, and a bubble canopy offering unmatched visibility.
To balance these cutting-edge features, General Dynamics took a pragmatic approach to components: of the 432 parts in the YF-16, 254 came from proven aircraft. The prototype incorporated systems from various successful platforms: the A-7’s environmental control system, the F-4’s nose wheel, B-58 “Hustler” main landing gear components (including recycled tires), the C-5A’s starter, and various electronics and equipment from the F-15 and F-111.
The prototype YF-16, tested only in clear weather, lacked radar capabilities but demonstrated impressive weapons integration versatility. During trials leading to its selection on January 14, the aircraft fired 12,948 20mm rounds and seven Sidewinder missiles at both subsonic and supersonic speeds, while also delivering ten 2,000-pound Mk-84 bombs. Removable 180-gallon fuel tanks supplemented its range.
With a wingspan of 30 feet and length of 47 feet, the YF-16 achieved a maximum weight of 27,000 pounds in air-to-ground configuration (limited to two Mk-84s) and 17,500 pounds in air-to-air setup. The production F-16 was designed to reach 33,000 pounds in maximum air-to-ground configuration, though landing gear limitations prevented testing at this weight.
The YF-16’s Pratt & Whitney F100-PW-100 turbofan engine, shared with the F-15, delivered 25,000 pounds of thrust with afterburner. This power gave the YF-16 a thrust-to-weight ratio exceeding 1:1 in the critical air combat speed range of Mach 0.8 to Mach 1.6. General Dynamics chose a single-engine design after studies showed only 20% of peacetime accidents stemmed from engine failure. While dual engines offered greater combat survivability, achieving adequate separation between engines would have compromised aerodynamics and performance. The F100 engine choice brought multiple benefits: proven reliability, commonality with the F-15, weight savings, reduced development costs, and 20-30% better fuel efficiency.
An Unexpected Maiden Flight
The YF-16 No. 1 took to the air unexpectedly during a high-speed taxi test at Edwards Air Force Base in late January 1974. The aircraft experienced severe lateral oscillations, prompting General Dynamics Chief Test Pilot Phil Oestricher to take off rather than risk a crash. The unplanned flight lasted 6 minutes. The Lightweight Fighter (LWF) program, initially scheduled for 18 months of flight testing, underwent rapid acceleration: first condensed to one year, then stripped of time constraints with manufacturers simply instructed to proceed “as fast as possible.”
YF-16 No. 1 (tail number 01567), sporting a distinctive white, red (wings), and blue color scheme for high visibility, completed its official first flight on February 2, 1974. During the 90-minute flight, it reached an altitude of 30,000 feet and a speed of 342 mph (550 km/h). By March 11, 1974, the Air Force announced that the YF-16 had achieved Mach 2.0 at 40,000 feet on its 20th flight. The second prototype, YF-16 No. 2 (tail number 01568), joined the program with its maiden flight on May 9, initially wearing an experimental “air superiority” camouflage featuring irregular sky blue and off-white patterns reminiscent of clouds. By year’s end, after completing the LWF trials, YF-16 No. 2 received a new paint scheme of two similar shades of gray with irregular patterns. Testing had revealed these grays offered superior concealment, whereas the original off-white surfaces occasionally caught sunlight, making the aircraft easily detectable to potential adversaries.
General Dynamics highlighted several program achievements: YF-16 No. 2 reached a maximum speed of Mach 2.02 in mid-August at high altitude and Mach 1.4 at 10,000 feet. In maneuverability tests, the YF-16 sustained turns up to 9G. The second prototype conducted all weapons integration testing. YF-16 No. 1 demonstrated remarkable reliability by completing six flights in a single day in July 1974. Without aerial refueling, it achieved a flight duration of 2 hours and 55 minutes; with refueling, it extended to 4 hours and 10 minutes. While the program targeted 300 flights within a year, the YF-16 exceeded expectations by completing 330 flights (417 hours and 20 minutes) in just ten months.
Polemics And Controversy
The Lightweight Fighter (LWF) program tests unfolded against an intense political backdrop, largely due to the planned replacement of F-104G Starfighters in four NATO countries. The program’s two competitors quickly emerged as leading contenders for this crucial contract. Defense Secretary James Schlesinger suggested in late April 1974 that the final choice would be between the YF-16 and YF-17, with the winner needing to develop a production version for the Air Force’s Air Combat Fighter (ACF) program and present a comprehensive proposal for European nations.
Several major American aerospace companies, including LTV, Rockwell, and Lockheed, expressed strong dissatisfaction with the selection process. Initially, the specifications indicated that data from the two selected LWF programs would be shared with all original bidders, allowing new ACF proposals that could either build upon existing LWF designs or introduce entirely new concepts. However, time pressures mounted. Just before four European defense ministers visited Edwards Air Force Base in mid-September to inspect the competing aircraft, the Air Force announced that the LWF evaluation winner would automatically become the ACF, with a substantial order of 650 aircraft.
General Dynamics claimed victory on January 14, 1975, sparking immediate controversy. Critics suggested the decision favored the powerful Texas congressional delegation, as Fort Worth housed General Dynamics’ main facility. However, the Department of Defense and Air Force maintained that technical merit drove their choice. Air Force Secretary John McLucas explained, “The YF-16 demonstrated significant advantages in agility, acceleration, turning radius, and endurance, particularly in transonic and supersonic flight regimes. Additional benefits included superior G-tolerance, cockpit visibility, and deceleration capabilities. While both aircraft performed admirably, the YF-16 met all program objectives, while the YF-17 fell slightly short of some goals. The performance gap narrowed during subsonic operations but widened considerably at supersonic speeds, highlighting the YF-16’s superior aerodynamics and reduced drag.”
General Stewart, who headed Air Force Systems Command, emphasized, “We optimized these aircraft for maneuverability and air superiority. The YF-16 proved clearly superior in this crucial speed range β ‘exceptionally agile’ best describes its performance.”
After selection, both YF-16 prototypes continued rigorous flight testing, focusing on specific performance metrics and handling characteristics. During the LWF evaluation phase, the YF-16 engaged in simulated combat against the F-4 Phantom II and demonstrated roughly 50% better performance in combat maneuvers. Test pilot Phil Oestricher noted that the YF-16 could execute maneuvers beyond any conventional fighter’s capabilities. However, this raised an important question: Would these impressive maneuvering qualities translate into an effective combat aircraft without compromising other essential capabilities? The transition from the YF-16 to the production F-16 would answer this question, with the first pre-production F-16 scheduled to roll out approximately 18 months later.