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F-16XL: The Fighter Jet Revolution That Almost Happened

F-16XL Fighter concept
F-16XL Fighter Concept. Image Credit: Creative Commons.

Key Points and Summary – In the early 1980s, the F-16XL emerged as a revolutionary redesign of the F-16, featuring a distinctive “cranked delta wing.”

-This experimental fighter offered double the payload or nearly double the range of a standard F-16, alongside higher speeds and early stealth features.

-Despite its vastly superior performance, the F-16XL lost the competition for a new strike fighter to the larger, twin-engine F-15E Strike Eagle.

-Insider accounts suggest the program was ultimately sidelined because its high capability and lower cost were perceived as a political threat to the then-developing, high-priority F-22 Raptor program.

The F-16XL Fighter Had It All..And Failed…

WARSAW, POLAND – The aircraft that was supposed to start a revolution in fighter performance rolled out of the Fort Worth, Texas, General Dynamics facility on 2 July 1982.

At first glance, the aircraft looked like a subscale version of another design from three decades hence – back when the factory was then a division of Convair Aviation, the B-58 Hustler.

But this aircraft was instead an F-16 that had been modified with a cranked delta wing.

The then-head of US Air Force (USAF) Aeronautical Systems Division (ASD) Lt. Gen. Lawrence Skantze, introduced the aircraft by saying that it was “our responsibility to take the fighter craft we have today and evolve those into higher performers, better performers, and improve their margin and hone the edge of their cutting abilities as the future goes before us.”

Meet the F-16XL 

The F-16XL was an example of that kind of geometric improvement in an aircraft design.

The final result of a cooperative program between General Dynamics and the USAF, this aircraft demonstrated, at a modest cost, that the F-16XL could deliver double the range or payload of the standard-design F-16 of the day.

The “father” of the F-16, Harry J. Hillaker, then became chief project engineer for the advanced versions of the aircraft.

He also had the level of experience required to lead these efforts.  Hillaker had been part of the advanced design effort for every primary aircraft produced at Fort Worth since 1942.

He held the lead engineering role on the F-16 program and later served as director of F-16 marketing before being tapped to lead the F-16XL development.

Hillaker said, as a lengthy article on the program explains, that “the objective of the F-16XL program was to achieve a logical evolution from the basic F-16 that would provide significant improvements in all mission performance elements.”

Performance Enhancement

The F-16XL design retained all the basic F-16 advantages, including low procurement and operating costs.

The primary objectives of the program were to enhance the range and payload of the aircraft; however, other aspects of its performance were also improved by the new design.

One was survivability at longer ranges.

The increased performance of the GE F110 engine installed in the two-seat F-16XL gave the aircraft 6,000 lbs more thrust.

This meant higher thrust in full military power, which is the top of non-afterburning performance, and increased penetration speed.

Simultaneously, the aircraft’s signature was managed by integrating some of the first- and second-generation signature management modifications to make the plane a more low-observable platform.

Also, increasing maneuver agility and reducing vulnerable areas improved the survival rate that would be required with a longer-range and deeper-penetration platform.

In this respect, the F-16XL was the forerunner to the practice of determining how to deliver weapons and lower the aircraft’s signature most effectively.

The writings on the program state that these improvements “resulted from the design team’s innovative approach to integrating the weapons and airframe rather than hanging weapons on in the conventional high-drag, destabilizing manner.”

Mission Accomplished

The design team was credited with achieving several notable objectives in enhancing mission performance.

An F-16XL in an air-to-surface mission it could carry twice the payload of the F-16A and at ranges of up to forty-four percent farther.

It could also do so without the need for external fuel tanks, while carrying four AIM-120 Advanced Medium-Range Air-to-Air Missiles (AMRAAM) and two AIM-9 Sidewinder infrared (IR) missiles.

With equal payload/weapons and then adding external fuel tanks, the mission radius could nearly double.

When configured for a solely air-to-air mission, an F-16XL with four AMRAAMs and two AIM-9s could go forty-five per cent farther than an F-16A and could do so while conducting a combat action that was equal to thirty per cent of its internal fuel.

The F-16XL could also dash supersonically with a load of bombs at either high or low altitude.

It could climb at high rates even loaded with bombs.

It had a speed advantage of up to eighty-three knots over the F-16A at sea level at military power setting (no afterburner) and a 311 knots advantage in afterburner at altitude while carrying a bomb load.

What Could Have Been

Two additional aspects of the F-16XL contribute to survivability.

One is an improved instantaneous maneuver ability, coupled with greatly expanded flight operating limits when carrying bombs.

A second is a reduced radar signature resulting from the configuration shaping.

Why Did the F-16XL Fail? 

Ultimately, executives involved in the program provided reasons for its failure to move forward after the initial prototypes.

One was that the F-16XL was competing with the first generation of the F-15E designs.  The USAF, said one designer, “will pick a bigger, twin-engine bomb truck over a single-engine aircraft every time.”

Another was that the aircraft, as often happens in the world of fighter designs, was “too good,” said another.

At various times, when what became the F-22 was a program in trouble, more than one designer stated that it could have easily been modified more extensively, made more stealthy, and could have performed much of the F-22’s mission at a much lower cost.

“This was too much of a threat to the program at the time and the XL had to be sidelined,” said one designer.

The aircraft was ultimately sent to NASA and leased to conduct supersonic laminar flow testing.

Like many chapters in aerospace history, this was an aircraft ahead of its time.

It is another example of “what could have been” that we will never know what the F-16XL was capable of.

About the Author: Reuben F. Johnson

Reuben F. Johnson has thirty-six years of experience analyzing and reporting on foreign weapons systems, defense technologies, and international arms export policy. Johnson is the Director of Research at the Casimir Pulaski Foundation. He is also a survivor of the Russian invasion of Ukraine in February 2022. He worked for years in the American defense industry as a foreign technology analyst and later as a consultant for the U.S. Department of Defense, the Departments of the Navy and Air Force, and the governments of the United Kingdom and Australia. In 2022-2023, he won two awards in a row for his defense reporting. He holds a bachelor’s degree from DePauw University and a master’s degree from Miami University in Ohio, specializing in Soviet and Russian studies. He lives in Warsaw.

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Reuben Johnson
Written By

Reuben F. Johnson has thirty-six years of experience analyzing and reporting on foreign weapons systems, defense technologies, and international arms export policy. He is also a survivor of the Russian invasion of Ukraine in February 2022. He worked for years in the American defense industry as a foreign technology analyst and later as a consultant for the U.S. Department of Defense, the Departments of the Navy and Air Force, and the governments of the United Kingdom and Australia. In 2022-2023, he won two awards in a row for his defense reporting. He holds a bachelor's degree from DePauw University and a master's degree from Miami University in Ohio, specializing in Soviet and Russian studies. He lives in Warsaw.

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