In May 1964, at Edwards Air Force Base, a stubby little jet with two enormous holes in its wings lifted straight up off the desert floor. The Ryan XV-5A Vertifan wasn't using rotors, tilting ducts, or vectored thrust. It was using fan-in-wing propulsion: two 62.5-inch-diameter lift fans buried flush inside the wings, plus a smaller one in the nose, all driven by tip-turbine exhaust diverted from a pair of General Electric J85-GE-5 turbojets. When the louvers above the fans closed, it was a conventional jet doing 547 mph. When they opened, it was a flying carpet.

The aircraft was built by Ryan Aeronautical in San Diego under a 1961 U.S. Army contract worth roughly $35 million for two prototypes (about $370 million today). The fan technology came from General Electric's X353-5B lift-fan system, which used a clever bit of fluid mechanics: hot exhaust from the J85s was ducted to the rim of each lift fan, where it spun small turbine buckets at the blade tips. This meant the fans produced about 2.6 times the thrust of the raw jet exhaust they consumed — a thrust augmentation ratio that made vertical takeoff actually affordable in fuel terms, unlike the Harrier's brute-force vectored thrust.

Why did it die?

• Two fatal crashes. On April 27, 1965, test pilot Lou Everett was killed when his ejection seat fired during a transition test — the airframe survived; the pilot didn't. A second prototype crashed on October 5, 1966, when pilot David Tittle ejected while inverted at low altitude during a hover demonstration.
• Transition complexity. The conversion between fan lift and jet cruise required precise scheduling of louvers, diverter valves, and throttles. 1960s analog flight controls couldn't reliably automate it.
• The Army lost VTOL. The 1966 Johnson-McConnell agreement gave fixed-wing combat aircraft to the Air Force. The Army's appetite for armed VTOL evaporated overnight.
• Vietnam. Helicopter doctrine consumed every available rotorcraft dollar through 1972.

Here's the case for 2026: the fan-in-wing concept's hardest problem was control authority during transition, and that problem is solved. Modern fly-by-wire systems run the F-35B's lift fan / roll-post / swivel-nozzle ballet at 400 Hz without breaking a sweat. Ryan's tip-turbine drive eliminates the F-35B's heavy shaft, clutch, and gearbox — the Rolls-Royce LiftSystem weighs about 4,500 lb and consumes 27,000 horsepower through a mechanical driveshaft running through the airframe. Tip-turbine drive replaces all that with ductwork.

Modern materials make it even more attractive. The original GE fans used steel rotors that ran hot and heavy. Ceramic matrix composite (CMC) tip turbines — already flying on the LEAP engine's HP turbine shrouds — could handle 2,400°F gas paths with a fraction of the weight. Carbon-fiber fan blades with hollow titanium leading edges (standard on the GE9X) would let the same fan diameter produce 40-60% more thrust.

The application that actually wants this: autonomous logistics VTOL. DARPA's ANCILLARY program and the Marines' Aerial Logistics Connector requirement both ask for 1,000-lb-payload VTOL with 300+ kt cruise. Tilt-rotors are mechanically baroque. Lift-plus-cruise quadcopters can't cruise efficiently. A fan-in-wing UAV with CMC tip turbines and modern FBW splits the difference — clean wing in cruise, no exposed rotors, no transition gymnastics that need a human pilot. Ryan was right; the louvers just needed software.