While the Bell XV-15 was proving tilt-rotors in 1977, Canada had already proven tilt-wings — a fundamentally different and arguably superior solution — almost a decade earlier. The Canadair CL-84 Dynavert, designed by Polish-Canadian engineer Karol "Karl" Frydrych starting in 1957, made its first transition from hover to forward flight on January 7, 1966. It was, by every metric that mattered, the most successful VTOL transport ever built up to that point. And Canada built four of them, flew them spectacularly, and then walked away.

The concept was elegantly brutal: rather than tilting just the engines (V-22) or just the rotors, the CL-84 tilted the entire wing through 100 degrees, with two Lycoming T53 turboshafts driving 14-foot interconnected propellers. A tail-mounted contra-rotating rotor handled pitch in the hover. Because the wing tilted with the props, the prop wash never blasted across a stationary wing — eliminating the catastrophic download penalty that costs the V-22 roughly 10% of its hover lift to this day.

The performance numbers were staggering for 1965:

• Cruise speed: 309 mph (517 km/h) — faster than any helicopter for the next 50 years
• Hover ceiling: 12,000 ft out of ground effect
• Payload: 12 troops or 4,000 lb of cargo, VTOL
• Transition time: Hover to full forward flight in 10 seconds

It demonstrated shipboard operations aboard USS Guadalcanal and USS Guam in 1972-73, performed at the Paris Air Show, and was evaluated by the U.S. Navy, Marines, Army, and Air Force simultaneously. Test pilots loved it. The Marines wanted 200 of them.

Why did it die? A combination of bad luck and worse politics:

• The first prototype (CF-VTO-X) crashed on September 12, 1967 due to a hydraulic pump failure in the propeller pitch-change mechanism — not an aerodynamic flaw. Both pilots ejected safely.
• The second prototype crashed in 1973, again from a mechanical (not design) issue.
• Canada's Liberal government under Trudeau was slashing defense spending; the 1971 White Paper on Defence killed Canadian funding.
• The U.S. military was bleeding cash into Vietnam and unwilling to adopt a Canadian airframe over domestic programs.
• Bell and Boeing were already lobbying for what would eventually become the JVX program — the V-22 — using tiltrotor, not tilt-wing.

Why now? The CL-84's two killers were both materials-science problems, not concept problems. The hydraulic pitch-change mechanism that destroyed the first prototype would today be a fly-by-wire electric actuator with triple redundancy — the same tech now flying on the F-35B's lift fan. The interconnected driveshaft cross-coupling the two engines (heavy, complex, lossy) becomes trivial with modern turboelectric distributed propulsion: spin both wings electrically from a single turbogenerator, eliminate the mechanical crossshaft entirely. Composite wing structures cut the empty weight by 25-30%. And the tilt-wing's fundamental advantage — no download penalty, cleaner aerodynamics in cruise — is exactly what the Army's Future Long-Range Assault Aircraft (FLRAA) program is paying billions to recover with the V-280 Valor, which still uses tiltrotor architecture.

One surviving Dynavert sits at the Canada Aviation and Space Museum in Ottawa. It is, quite literally, a working answer to a question the Pentagon is currently spending $70 billion to re-ask.