Timelines · Aviation · 7 of 9
A hundred passengers at twice the speed of sound — the only supersonic airliner that ever worked.
1969·Mach 2.04 (~2 180 km/h)·7 220 km·4× RR/Snecma Olympus 593 reheated turbojets, 169 kN each·92–128
· THE STORY
Concorde crossed the Atlantic in under three and a half hours, cruising at Mach 2 with a hundred passengers drinking champagne — for 27 years, twice as fast as any airliner before or since. Its needle nose drooped down so the pilots could see the runway, and its delta wing let the same aircraft cruise faster than a rifle bullet yet land at ordinary airport speeds.
· WHY IT MATTERED
Fighters can dash supersonic on afterburner for minutes; Concorde held Mach 2 for hours on dry engines alone. The whole design — intake, engine and wing — was tuned so supersonic cruise was its efficient operating point, a feat no other airliner and few military jets have matched. The demo’s reheat toggle shows why afterburning all the way would have been impossible.
· WHY IT MATTERED
At cruise, the moving ramps in Concorde’s intakes slowed the Mach-2 stream to gentle subsonic speeds, recovering so much pressure that the intakes contributed the majority of the propulsion system’s compression and a huge share of its thrust. The engine behind them saw easy air — the box it sat in did the hard work.
· WHY IT MATTERED
A slender ogival delta flies clean at Mach 2, and at low speed generates swirling leading-edge vortices that let it land at 300 km/h without flaps or slats — the nose-high, drooped-nose landing attitude is that vortex lift at work.
· WHY IT MATTERED
Skin friction heated the nose to ~127 °C at Mach 2.04 — the ceiling for its aluminium structure, and the reason Concorde stretched several centimetres in flight. The cruise Mach number was set by metallurgy, not thrust: with more exotic materials it had thrust to go faster.
· TRY IT
The same live turbojet model, preset to Concorde’s Mach-2 cruise. Flick the reheat toggle: thrust jumps, but look at what happens to TSFC — that fuel bill is why Concorde lit the burners only for take-off and the push through Mach 1, and why being able to cruise dry made a supersonic airliner possible at all.
Timelines · Aviation · go deeper · Concorde
Anyone can go supersonic with afterburners. Staying there with them OFF was the real trick.
transonic push only·Mach 2, afterburners off·shock staircase, free compression·Mach 2 at 18 km — only
· THE IDEA
Afterburner — reheat — is brute force: dump fuel into the exhaust and buy enormous thrust at ruinous fuel burn. Concorde used it only to punch through the draggy transonic region, then switched it off and did something no other airliner has done since: cruise at Mach 2 on dry thrust alone, efficiently, for hours. The secret sat ahead of the engines — an intake so clever it did half the engine’s job before a single blade turned.
· WHY IT MATTERS
Drag piles up viciously around Mach 1 — the transonic hump. Rather than carry engines big enough to cruise through it dry, Concorde lit its afterburners for a few minutes to shove through, then shut them down. Brute force as a tool, not a lifestyle: the fuel-burn arithmetic of reheat would have emptied the tanks over the Atlantic.
· WHY IT MATTERS
A jet engine’s blades cannot swallow supersonic air. Concorde’s intake ramps generated a staircase of shockwaves that slowed the Mach 2 stream to about Mach 0.5 in the space of a few metres — and compression is exactly what shocks do, so the intake delivered air already squeezed, for free. At cruise the intakes contributed a remarkable share of the total thrust; the engines finished what the aerodynamics started.
· WHY IT MATTERS
Everything about the aircraft — the slender delta, the intake geometry, the engine cycle — was tuned for one condition: Mach 2 at 18 km. There it was genuinely efficient; everywhere else it paid. That single-mindedness is why Concorde was magnificent, why only fourteen ever carried passengers, and why nothing has replaced it.