YF-17 Cobra: The Air Force passed on this fighter (the Navy said yes)

What you need to know: In the late 1960s, the Fighter Mafia, led by John Boyd, challenged traditional military aviation by advocating lightweight, maneuverable fighter aircraft. Their efforts led to the development of the YF-16 and YF-17 as part of the USAF Lightweight Fighter program.

-While the YF-16 won out and became the F-16 Fighting Falcon, the YF-17 found a new home in the US Navy.

-The Navy, looking for a more affordable and versatile fighter, transformed the YF-17 into the F/A-18 Hornet. Today, the F/A-18 is a mainstay of naval aviation, proving that even a “loser” can become an icon.

How the Combat Mafia Shaped the YF-17 and the Rise of the F/A-18 Hornet

In the late 1960s, a group of U.S. Air Force officers challenged orthodoxy, gaining notoriety and a somewhat derogatory nickname: The Fighter Mafia.

“The Mad Major” John Boyd unofficially led the Fighter Mafia. Boyd was a fighter pilot and military strategist, known for his confrontational style and his intensely passionate pursuit of his interests. Boyd, together with mathematician Thomas P. Christie, developed a theory that would be the linchpin for the Fighter Mafia’s reform efforts: the energy maneuverability theory.

The energy maneuverability theory, which Boyd and Christie published in a two-part text, can be reduced to one basic formula: Ps – V (TD/W). Simply put, the formula reliably predicts aircraft performance. And those predictions indicated that excess weight would have debilitating effects on an aircraft’s maneuverability. So with this now widely accepted information in hand, Boyd and his Fighter Mafia began advocating for a new type of fighter aircraft, one with a high thrust-to-weight ratio, high maneuverability, and a gross weight of less than 20,000 pounds. (For comparison, the F-15 Eagle weighs 45,000 pounds).

Boyd wanted an aircraft capable of “fast transients,” meaning rapid changes in speed, altitude and direction. The result would be a superior fighter, able to quickly gain or lose energy, and thus outmaneuver an opponent; this hypothetical fighter, while on the offensive, would be able to stick to an enemy fighter, and while on the defensive, it could force an enemy to overshoot.

How the YF-17 was born

The specifications the Fighter Mafia sought coalesced into a formal evaluation program known as the Lightweight Fighter (LWF) program, intended to spur the development of an aircraft that met the theory of energy maneuverability. Two lightweight but powerful aircraft were built to compete in the LWF evaluation: the General Dynamics YF-16 and the Northrop YF-17.

The YF-16 – with superior acceleration, endurance, turn rate and rate of climb compared to the YF-17 – won the LFW evaluation. The Air Force placed an order for five fighter wings worth of YF-16s. When the aircraft entered service in 1980, it became known as the F-16 Fighting Falcon. Still, the YF-17, the loser of the LFW evaluation, caught the attention of the US Navy, which was also looking for a lightweight, low-cost fighter.

In the 1970s, the US Navy realized that the F-14 was too large and expensive to be used as a replacement for their entire fighter fleet. Looking for a cheaper alternative, the Navy went along to observe the USAF’s LFX program. While the USAF selected the YF-16, the Navy found the twin-engine YF-17 intriguing.

The Navy didn’t need a pure dogfighting fighter capable of defeating everything else in the air. Thus, the YF-17’s inability to keep pace with the YF-16 was not disqualifying. Furthermore, the Navy strongly preferred twin-engine aircraft – for reasons of engine redundancy (i.e. safety) during the acutely vulnerable catapult launches from aircraft carriers.

The YF-17 was a perfect fit. The Navy further tinkered with the design, scaled up the aircraft and created a larger version. The larger version became the Block IF/A-18 Hornet, variants of which are still in use today (and are currently the star of the world’s highest-grossing movie). Not bad for an aircraft that ‘lost’ its evaluation program half a century ago.

About the Author: Harrison Kass

Harrison Kass is a senior defense writer with more than 1,000 published articles. A lawyer, pilot, guitarist and minor professional hockey player, he joined the United States Air Force as a Pilot Trainee but was medically discharged. Harrison holds degrees from Lake Forest College, the University of Oregon and New York University. He lives in Oregon and listens to Dokken regularly.

Image credits: Creative Commons.