The General Electric J85 first ran on a test stand in 1956. Eisenhower was president. The Soviets had not yet launched Sputnik. Sixty-five years later, the same engine — virtually unchanged in its core architecture — is being kept alive by a fresh $178 million Air Force contract that will run through 2030.

It is, by some distance, the longest continuous production run of any military jet engine in history. And the Pentagon’s reason for keeping it going is simple: the aircraft that depend on it are not retiring any time soon, and nobody wants to pay to redesign them.

The Engine That Wouldn’t Die

The J85’s design brief was simple: build the smallest possible afterburning turbojet that could power a target drone. GE delivered, the engine worked, and within five years it had been adopted for crewed aircraft — first the Northrop T-38 Talon trainer, then the F-5 Freedom Fighter, then the A-37 Dragonfly attack jet of Vietnam fame.

What makes the J85 special is not its raw performance — many modern engines outperform it on every metric — but its sheer reliability and ease of maintenance. A J85 can be removed from a T-38 by two ground crew with hand tools in under three hours. Modern turbofans typically require a full hangar and overhead crane.

Why the Pentagon Keeps Buying It

The T-38 Talon is supposed to be replaced by the new Boeing T-7A Red Hawk, which uses a modern GE F404 derivative. But the T-7A’s production schedule has slipped repeatedly, and the existing 500-aircraft T-38 fleet has to keep flying training sorties at the same rate while the changeover happens. That means continued spares, continued depot overhauls, and continued new-build engines — at $178 million across the next four years.

The Export Math

Even if the USAF retired its J85 fleet tomorrow, GE would have a queue of customers asking for engines. Twenty-five air forces still operate F-5 Tigers — Switzerland, Iran (yes, still flying its 1970s Tigers), Brazil, Singapore, Mexico, Turkey, and the United States itself, which uses Tigers as Navy aggressor aircraft. Every one of them needs new J85s on a rolling cycle.

That makes the J85 the rare case where a 70-year-old design is more profitable to GE than some of its modern engines, simply because the development costs were paid off in the Kennedy administration. Every new engine is essentially pure margin.

A 2030s Retirement, Maybe

The realistic retirement window for the J85 is somewhere in the late 2030s, when the T-7A finally reaches full operational tempo and the last F-5 squadrons either get European or American replacement aircraft. Until then, the engine that started its career powering target drones for Eisenhower will keep going — quietly, reliably, and at a price the Pentagon cannot find a reason to refuse.

Sources: Defence Blog, US Air Force contract announcement, GE Aviation press release.