What engines did Concorde use for supersonic flight?

Concorde used four Rolls-Royce/Snecma Olympus 593 Mk 610 afterburning turbojet engines. Each production engine developed about 31,000 lbf (138 kN) without reheat and 38,050 lbf (169 kN) with it. Reheat helped at take-off and through transonic acceleration; Concorde then cruised near Mach 2.02 with reheat switched off.

In our Aviation & Real-World Flying coverage, this distinction matters: the Olympus 593 was the gas-turbine engine, while Concorde’s intake, reheat and variable exhaust nozzle formed a tightly matched propulsion installation. Treating the quoted engine thrust as the whole Mach 2 story leads to several common errors.

What engine did production Concorde use?

Production Concordes used the Rolls-Royce/Snecma Olympus 593 Mk 610, a two-spool axial-flow turbojet with reheat. Four engines were installed in two paired nacelles beneath the wing.

The quoted thrust values are reference ratings, not fixed thrust delivered at every speed and altitude. Actual installed thrust changes with atmospheric conditions, engine setting, intake pressure recovery, nozzle geometry and flight Mach number. Dry thrust means operation without reheat; it does not mean that the main combustion chambers have stopped burning fuel.

The Olympus family had Bristol military-engine ancestry, but the 593 was extensively developed for sustained civil supersonic flight. Prototype and pre-production Concordes used earlier development standards, which is why figures taken from test aircraft do not always agree with Mk 610 production specifications. Our full set of production Concorde weights and performance figures provides the wider aircraft context.

How does Olympus 593 thrust compare with Concorde’s maximum take-off weight?

At Concorde’s 408,000 lb maximum take-off weight, the four engines had a combined quoted maximum reheat thrust of 152,200 lbf. Dividing those figures gives a simple static thrust-to-weight ratio of about 0.37, but that is not a measure of Mach 2 cruise performance.

An aeroplane does not need thrust equal to its weight because the wing supports the weight; thrust must overcome drag and provide acceleration. At supersonic speed, intake pressure recovery, exhaust-nozzle performance, altitude and airframe drag matter more than a comparison between take-off weight and a static engine rating.

Did Concorde have afterburners?

Yes. Concorde had afterburners, although its crews and technical documents called the system reheat. Extra fuel was sprayed and burned in the jet pipe downstream of the turbines, raising exhaust velocity and thrust without passing the additional combustion through the turbine stages.

A normal flight used reheat during two main periods:

• Take-off: reheat supplied the additional thrust needed by a heavy aircraft using a relatively small delta wing at low speed. It was cancelled after departure according to the climb and noise-abatement procedure.
• Transonic acceleration: reheat was selected again near Mach 0.95 to help the aircraft through the high-drag region around Mach 1, then switched off at roughly Mach 1.7.

Concorde did not use reheat throughout supersonic cruise. After it was cancelled near Mach 1.7, the aircraft continued towards Mach 2 using high dry power, efficient intake and nozzle operation, and the lower aerodynamic drag available at cruise altitude. The precise selection points could vary with operating procedure and conditions; our explanation of the Mach 2 acceleration, climb and cruise profile puts those phases in order.

How did the Olympus 593 engines make Mach 2 possible?

The Olympus 593 could sustain Mach 2 only as part of Concorde’s complete propulsion system. Its variable intakes and exhaust nozzles were as important at supersonic speed as the turbojet core between them.

1. The variable intake controlled Mach 2 airflow. Movable ramps and spill doors created and positioned a sequence of shock waves. These slowed the incoming air to subsonic speed before it reached the compressor while recovering much of its kinetic energy as pressure.
2. The turbojet core compressed and heated the air. Low- and high-pressure compressor sections raised its pressure, fuel burned in the combustion chambers, and turbines extracted enough energy to drive the two compressor spools.
3. Reheat added temporary thrust. Burning more fuel downstream of the turbines helped during take-off and transonic acceleration, where the available dry thrust alone did not provide the required performance margin.
4. The variable exhaust system matched the flight condition. Changing nozzle geometry maintained suitable engine back-pressure and expanded the exhaust efficiently as engine power, altitude and Mach number changed.

At Mach 2, the compressor still received subsonic air. Concorde was therefore not a ramjet, nor did it change into one during cruise: the Olympus compressors, combustion chambers and turbines continued operating throughout the flight.

What was a Concorde intake unstart?

An intake unstart occurred when the carefully controlled shock-wave pattern broke down or moved out of position, causing an abrupt loss of pressure recovery. Drag could rise sharply on the affected side, producing a noticeable yaw as well as disturbing airflow to the engine.

Concorde’s automatic intake-control system moved the ramps and spill doors to keep the shock system stable and assist recovery. An intake unstart was not simply another name for an engine flameout or compressor stall, although severe inlet-flow disruption could affect the engine behind it.

Why did Concorde use turbojets instead of turbofans?

Turbojets gave Concorde high specific thrust from engines with a relatively small frontal area. That allowed narrow nacelles, reduced supersonic installation drag and produced the high exhaust velocity suited to a 1960s airliner designed for sustained Mach 2 flight.

A high-bypass turbofan has a large fan and moves a greater mass of air at lower velocity, which is highly efficient for subsonic airliners but creates difficult diameter, intake and drag compromises at Mach 2. This does not mean every turbofan is incapable of supersonic flight: low-bypass afterburning turbofans are widely associated with supersonic military aircraft.

The Olympus installation’s disadvantages were severe noise and heavy fuel consumption during low-altitude, subsonic and reheat operation. Concorde accepted those penalties to obtain efficient high-speed cruise from the technology and materials available during its development.

Could the Concorde engines alone make the aircraft supersonic?

No. The engines supplied thrust, but Concorde also required its slender ogival delta wing, low-wave-drag fuselage, variable intakes, heat-tolerant structure, fuel-transfer trim system and carefully managed climb profile.

Fuel was moved aft as the aerodynamic centre of lift shifted during acceleration, reducing the control deflection and trim drag that would otherwise waste engine thrust. Our account of how Concorde’s wing, fuel trim and propulsion systems worked together covers those supporting systems without treating the Olympus as an isolated component.

Why does a simulated Concorde lose speed when reheat is switched off?

A simulated Concorde usually loses speed after reheat cancellation because it is too low, too heavy, incorrectly trimmed, carrying excess drag or using the wrong intake configuration. A mistake we see constantly is treating reheat as an always-on Mach 2 switch rather than temporary assistance for specific flight phases.

1. Check the cancellation point. Do not switch off the second period of reheat immediately after passing Mach 1. A representative Concorde profile retains it until roughly Mach 1.7, although the exact add-on procedure takes precedence.
2. Confirm a clean configuration. Landing gear, airbrakes or other drag-producing surfaces must be fully retracted. Small configuration errors become costly at supersonic speed.
3. Check weight, altitude and flight path. A heavily loaded aircraft forced towards Mach 2 at low altitude may not accelerate correctly. Follow the model’s climb-and-acceleration schedule rather than trying to reach cruise speed in level flight too early.
4. Set the correct centre of gravity. Concorde transferred fuel aft for supersonic flight to reduce trim drag. Depending on the add-on, this may be automatic, manually controlled or only approximated.
5. Verify intake operation. Some models schedule the ramps and spill doors automatically; others expose part of the system to the crew. An incorrect mode can reduce pressure recovery or trigger a simulated intake unstart.

Leaving reheat selected for the entire cruise hides the underlying problem and destroys realistic fuel planning. Add-ons differ substantially in how deeply they reproduce the engineer’s station and intake controls, so compare the model’s indications with our guide to the real engine, reheat and intake controls in Concorde’s cockpit.