In August 1972, a black delta-winged aircraft with a drooping nose and four engines stacked underneath its belly lifted off the runway at Zhukovsky. It looked like the North American XB-70 Valkyrie's Soviet cousin. It flew like nothing else in the USSR's arsenal. And within three years, it was in a museum.

The Sukhoi T-4 — nicknamed "Sotka" (сотка, "the hundred," for its 100-tonne class) — was the Soviet answer to the American B-70 and the RS-70 reconnaissance-strike variant. Design began in 1961 under Naum Chernyakov at OKB Sukhoi, aimed at a Mach 3 anti-carrier strike platform to hunt US Navy battle groups with Kh-45 supersonic cruise missiles.

The engineering was staggering:

• Airframe: 74% titanium alloys (VT-20, VT-22) and stainless steel — necessary because Mach 3 skin temperatures hit ~330°C. Sukhoi had to invent new welding techniques and pioneered electron-beam welding at industrial scale for aviation-grade titanium.
• Engines: Four Kolesov RD-36-41 turbojets, 16,000 kgf thrust each, arranged in a "packet" under the fuselage — the same layout as the XB-70. Mach 3.0 cruise at 24,000 meters.
• Avionics: The first fully fly-by-wire aircraft in Soviet history, using a quadruplex-redundant analog flight control system. No mechanical linkages to the flight surfaces at all.
• Drooping nose: Like the Concorde and Tu-144, the nose folded down for takeoff/landing visibility, then locked flush for supersonic flight.

First flight was August 22, 1972 with Vladimir Ilyushin at the controls. The T-4 flew ten times, reached Mach 1.36 (well below its design speed — the flight envelope was being expanded incrementally), and behaved beautifully. A second airframe was 95% complete. A third was on the jigs.

Then Andrei Tupolev happened. The T-4 was competing for the same production capacity Tupolev wanted for what would become the Tu-160 Blackjack. Tupolev, the elder statesman of Soviet aviation, lobbied hard. In 1974 the program was quietly suspended; in 1976 formally cancelled. The reason cited was cost — 1.3 billion rubles spent, projected 2 billion more for production tooling. The real reason was politics. The completed prototype sits at the Central Air Force Museum in Monino to this day.

Why it deserves resurrection in 2026: Every technical obstacle that made the T-4 monstrously expensive has collapsed.

• Titanium manufacturing: Friction stir welding and additive manufacturing (electron beam melting from companies like Norsk Titanium and Sciaky) now produce aerospace-grade titanium parts at ~30% the cost of subtractive machining. The T-4's core cost driver — hand-welding titanium honeycomb — is a solved problem.
• Fly-by-wire: The analog quadruplex system Sukhoi hand-built is now a $50,000 COTS avionics package.
• Propulsion: Modern variable-cycle engines (like GE's XA100) can cruise efficiently at Mach 2.5–3 without the fuel burn that made the T-4 uneconomical. The RD-36-41 burned kerosene at a rate that gave it a combat radius of only ~3,000 km. A modern equivalent would nearly double that.
• Mission relevance: Long-range, high-speed penetrating strike against maritime targets is exactly the Pacific-theater problem the US Navy and PLAN are grappling with in 2026. Hypersonic weapons need hypersonic-adjacent carriers.

The T-4 was a 100-ton titanium proof that the Soviets could build anything the Americans could. It was killed by a bureaucratic knife-fight, not physics.