Concorde engines explained: see how four Olympus 593 turbojets, reheat and variable intakes sustained Mach 2 cruise without afterburners.
Concorde used four Rolls-Royce/Snecma Olympus 593 Mk 610 afterburning turbojets. Reheat supplied extra thrust for take-off and transonic acceleration, while variable-geometry intakes slowed and compressed Mach 2 airflow before it reached the compressors. Once established in cruise, Concorde could maintain about Mach 2 without reheat.
Which Olympus 593 engine did production Concorde use?
Production aircraft used the Olympus 593 Mk 610, a two-spool axial-flow turbojet jointly developed by Rolls-Royce and Snecma. Prototypes and pre-production Concordes used earlier Olympus 593 standards, which explains why specifications sometimes differ between references.
| Feature | Production Concorde specification |
|---|---|
| Engines | Four Olympus 593 Mk 610 turbojets |
| Installation | Two paired underwing nacelles |
| Dry thrust | About 31,000 lbf per engine |
| Thrust with reheat | About 38,050 lbf, or 169 kN, per engine |
| Supersonic cruise | Approximately Mach 2 with reheat off |
The Olympus family began as a Bristol engine design, but the 593 was extensively adapted for sustained civil supersonic operation. Our account of Concorde’s propulsion development and operating history explains how that engine programme fitted into the aircraft’s wider story.
How did Concorde’s engines make Mach 2 possible?
The Olympus core was only one part of a closely integrated propulsion system. Concorde’s intakes, turbojets, reheat system and variable exhaust geometry had to work together across take-off, transonic acceleration and Mach 2 cruise.
- Variable-geometry intakes controlled the incoming air. At Mach 2, free-stream air could not enter the compressor at supersonic speed. Movable ramps and spill doors formed controlled shockwaves, slowed the flow to subsonic speed and converted much of its velocity into pressure.
- The turbojet core compressed and heated the air. Fuel burned in the compressed airflow, and the turbines extracted enough energy to drive the compressors. This followed the same compression, combustion, turbine and exhaust cycle used by jet engines generally.
- Reheat supplied temporary extra thrust. Additional fuel was burned downstream of the turbine, increasing exhaust energy without sending that combustion through the turbine. This helped Concorde overcome high take-off requirements and the sharp rise in drag around the speed of sound.
- The exhaust system matched the flight regime. Variable nozzle geometry expanded and accelerated the exhaust efficiently as speed and engine pressure changed.
At cruise speed, ram compression in the intake did a substantial part of the pressure-rise work before air reached the engine. That did not make Concorde a ramjet: its Olympus engines still used compressors, combustion chambers and turbines throughout the flight.
The intake also prevented a serious failure mode called an intake unstart. If the carefully positioned shock pattern collapsed, pressure recovery fell abruptly and drag increased on that side, producing a strong yaw. Concorde’s automatic intake controls moved the ramps and doors to keep the airflow stable and help the intake recover.
Did Concorde use afterburners throughout the flight?
No. Concorde called its afterburning system reheat, and used it only during selected phases. In a normal profile, reheat was used for take-off, cancelled after departure, selected again near the transonic region and switched off at roughly Mach 1.7. The aircraft then continued accelerating and cruised near Mach 2 on dry thrust.
A mistake we see often in simulation is leaving reheat engaged for the entire supersonic cruise. That is neither an authentic profile nor workable fuel planning. If a simulated Concorde cannot settle near Mach 2 after reheat is cancelled, check aircraft weight, climb schedule, fuel-transfer trim, extended landing gear or airbrakes, and whether the add-on models automatic intake scheduling.
Why did Concorde use turbojets instead of turbofans?
Turbojets suited Concorde because they provided high specific thrust with a relatively small frontal area. Their fast exhaust stream was effective at Mach 2, while the narrow installation reduced nacelle size and supersonic drag.
The trade-off was poor fuel economy and high noise during subsonic and low-altitude operation, especially with reheat selected. A high-bypass turbofan is much more efficient on a conventional subsonic airliner, but its large fan and slower bypass stream are not naturally suited to Concorde’s 1960s Mach 2 design. This does not mean every turbofan is incapable of supersonic flight; low-bypass engines power many supersonic military aircraft.
Could the engines alone make Concorde supersonic?
No. The engines provided the thrust, but Concorde also needed its slender ogival delta wing, low-wave-drag fuselage, heat-tolerant structure, fuel-transfer trim system and carefully managed climb profile. Our explanation of how Concorde’s complete airframe and flight systems worked together covers those supporting elements.
Concorde’s defining achievement was therefore not simply fitting four powerful engines. It was matching the Olympus turbojets to intakes and nozzles that remained efficient from a standing start to sustained Mach 2 cruise, without relying on fuel-hungry reheat for the cruise itself.