Summary and Key Points: The F-16 Fighting Falcon, a critical component of the U.S. Air Force for over five decades, made headlines when it was cleared for use by Ukraine. Among its many variants, the F-16XL stands out for its unique design and capabilities, although it never entered service.

-Developed as a contender for the Enhanced Tactical Fighter competition, the F-16XL lost to the F-15E Strike Eagle but found a second life with NASA. The F-16XL featured a cranked arrow wing design that offered greater lift, maneuverability, and range than the base F-16.

-Today, the F-16XL prototypes are preserved as iconic examples of innovative aircraft design.

The F-16XL: A Forgotten Falcon That Soared with NASA

The F-16 Fighting Falcon made headlines last year when the White House granted Ukraine the green light to fly them amidst the ongoing invasion.

The American-made supersonic multirole fighter aircraft was initially designed for the U.S. Air Force more than five decades ago. While the platform may be aging, it plays a critical role in the service’s fleet.

Over the last fifty years, several Fighting Falcon variants emerged, all featuring enhanced capabilities designed to keep the platform relevant in the modern era.

However, not all these variants made it to the service phase.

Notably, General Dynamics’ F-16XL was turned over to NASA a few years after losing the USAF’s Enhanced Tactical Fighter competition to the F-15E Strike Eagle.

The Fighting Falcon Platform

Following the lessons learned in the Vietnam War, U.S. officials recognized the need for an air superiority fighter.

Engineers outlined that a small, lightweight aircraft that could maneuver with minimal energy loss would be an ideal fit. The Air Force initially opposed the Advanced Day Fighter concept as the service felt it would jeopardize its F-15 Eagle program.

Ultimately, however, the idea of competitive prototyping was finalized and the Lightweight Fighter proposal was funded. By the 1970’s, the F-16 Fighting Falcon was designed.

Introducing the F-16XL

Shortly after manufacturer General Dynamics was awarded the Lightweight Fighter program contract, subsequent Fighting Falcon variants were conceptualized.

The Air Force desired a replacement fighter for its F-111 Aardvark and McDonnell Douglas submitted its new Fighting Falcon design to go up against the new F-15E Eagle. The USAF ultimately awarded McDonnell Douglas the contract. However, this wasn’t the end of the rope for the F-16XL idea.

The F-16XL’s NASA legacy

Two of these F-16XL prototypes referred to by their serial numbers #849 and #848 were eventually relegated to NASA’s Langley Research Center. Both jets were used in a variety of experiments that only concluded in the late 1990’s.

In 1995, F-16XL #849 participated in a sonic boom study where it successfully flew 200 feet behind a NASA SR-71 Blackbird to ascertain the boundary of the airframe’s supersonic shockwave. NASA heavily modified the two Fighting Falcon variants, installing a turbine-drive suction system and a thickened left-wing pulled in boundary layer air flowing over the wing.

The F-16XL was designed with a cranked arrow shape that accomplished greater lift than the base F-16.

As Alex Hollings from Sandboxx described it, “This new wing design, which saw a 50-degree angle near the root of the wing for supersonic performance and a 70-degree angle where the wings extended for subsonic handling.” Weighing nearly 600 pounds less than earlier variants, the F-16XL possessed greater maneuverability. The F-16XL could also carry twice the ordinance of the F-16A and deliver it 50% farther.

While the F-16XL prototypes are currently sitting in storage at the Air Force Flight Center Museum at Edwards and on display at the Museum Air Park, they are still revered by aviation buffs.

About the Author: Maya Carlin 

Maya Carlin, National Security Writer with The National Interest, is an analyst with the Center for Security Policy and a former Anna Sobol Levy Fellow at IDC Herzliya in Israel. She has by-lines in many publications, including The National Interest, Jerusalem Post, and Times of Israel. You can follow her on Twitter: @MayaCarlin. 

All images are Creative Commons.