“We climbed at more than 20,000 feet per minute, leaping from 4,000 to 27,000 feet in sixty-seven seconds. Jim eased the power back while turning into the supersonic corridor and getting cleared by Edwards Control to begin a supersonic run,” F. Clifton Berry wrote after riding in the F-16XL.

“Jim applied afterburner and the aircraft accelerated smoothly from Mach 0.95 through 1.0 and to 1.2 in seconds. Even with the heavy bomb load aboard, the aircraft went supersonic without a tremble. Handling characteristics at mach 1.2 with the heavy ordnance load were remarkably similar to those of the standard F-16 without bombs.”

The F-15E, on the other hand, offered only 15 hardpoints–which it’s important to note, is still a lot. The F-15E also delivered a higher top speed (Mach 2.5 versus 2.05) and a higher service ceiling at 60,000 feet (compared to the F-16XL’s 50,000). Most importantly, however, the F-15E leveraged not one, but two engines. Because these aircraft were intended to fly deep into enemy airspace without much support, the Air Force believed it was likely that these planes would see a great deal of anti-aircraft fire. Having two engines meant one could be damaged by enemy fire, but the aircraft could still limp home on the other.

The F-16XL may have been one of the most capable fighters to never make it into production

It was likely the perceived survivability of two engines, in conjunction with the lower cost of development, that saw the F-15E win the contract. But many within the Air Force saw the F-15E’s win as bittersweet. The Strike Eagle was indeed an incredibly capable platform, but the F-16XL’s fans felt as though the fighter wasn’t meant to compete with the Strike Eagle, so much as support it–much like the F-16 and F-15 support one another today. Like the YF-23 that lost to Lockheed Martin’s F-22 Raptor, the F-16XL has since been remembered as an aircraft that might have been better than the jet we ultimately got… with concerns about dollars and cents making the decision, rather than maximum capability.

Of course, that may not be an entirely fair assessment. The F-16XL was indeed a capable aircraft, but the F-15E has since proven itself in combat time and time again. The Strike Eagle was clearly not a bad choice, but with the F-16XL’s incredible chops in mind, there could be little doubt that the Air Force would have been better off with both of these capable fighters in their stable… if only money truly were no object.

Instead of fighting alongside the Strike Eagle as many hoped, the F-16XL program found its way to NASA, where both prototypes participated in a number of aeronautical research projects. In fact, some of the tests conducted using the F-16XL would go on to play a role in developing the supercruise capability for America’s top-tier air superiority fighter of today, the F-22 Raptor.

This article first appeared at Sandboxx.

Image: Wikipedia.