See how aircraft carrier catapults use steam or electromagnetic force, attach to aircraft, and set the correct power for a safe launch.
In real-world carrier aviation, catapults launch aircraft by coupling a deck shuttle to the aircraft’s nose-gear launch bar, holding the aircraft at take-off power, then accelerating the shuttle along the deck. Steam pressure or electromagnetic force supplies enough extra acceleration for the aircraft to reach safe flying speed at the bow.
For our Aviation & Real-World Flying readers, the key point is that a catapult accelerates the aircraft horizontally; it does not throw it upwards. Engine thrust, ship speed and wind over the deck all contribute to the airspeed available when the aircraft leaves the carrier.
How does an aircraft carrier catapult launch work?
A catapult launch is a controlled sequence of alignment, attachment, tensioning, engine run-up and rapid acceleration.
- Position the aircraft: Deck crew align its nosewheel with the catapult track. A jet-blast deflector is raised behind jet aircraft where required.
- Connect the launch gear: On most present-day carrier aircraft, a hinged launch bar on the nose gear engages the catapult shuttle. A holdback bar connects the aircraft to a deck fitting so it cannot creep forwards during tensioning and engine run-up.
- Tension the system: The shuttle moves forwards slightly to remove slack. Deck crew verify the attachment, control surfaces, aircraft configuration and clear deck ahead.
- Set launch power: The pilot advances the engines to the prescribed setting and completes the aircraft-specific checks. Catapult power is set from approved launch data rather than estimated by the pilot or deck crew.
- Authorise the launch: Once the pilot, launch officer and catapult crew are satisfied, the launch command reaches the catapult controls. Procedures and hand signals vary between carrier types and navies.
- Fire the catapult: The holdback fitting releases under the designed launch load while the shuttle pulls the aircraft forwards. At the end of the stroke, the launch bar separates from the shuttle and the aircraft continues over the bow under its own engine power.
The catapult stroke takes only a few seconds. Our explanation of the complete carrier take-off and recovery sequence covers how this launch fits into wider flight-deck operations.
What connects the aircraft to the catapult?
Most present-day catapult-compatible aircraft use a nose-gear launch bar, but this arrangement is not universal. Older naval aircraft often used a bridle connected to reinforced points on the airframe; the bridle linked the aircraft to the shuttle and fell away after launch.
The launch bar and holdback bar have different jobs. The launch bar pulls the aircraft forwards, while the holdback assembly restrains it until catapult force reaches the release load. Confusing the two is a common mistake in simplified diagrams and flight simulators.
How do steam catapults and EMALS differ?
Steam catapults drive pistons with pressurised steam, while the Electromagnetic Aircraft Launch System, or EMALS, moves the shuttle with a linear electric motor.
| Feature | Steam catapult | EMALS |
|---|---|---|
| Driving force | Steam enters cylinders beneath the deck and pushes pistons connected to the shuttle. | Successive linear-motor sections create an electromagnetic field that drives an armature connected to the shuttle. |
| Power control | A metered steam charge and launch-valve operation determine the available force. | Electronic controls regulate force throughout the launch stroke. |
| Main machinery | Steam supply, cylinders, seals, valves and water brakes. | Electrical generation, energy storage and conversion equipment, controls and linear motors. |
| Force profile | Power is adjusted for each aircraft, but the acceleration curve is less flexible. | The acceleration curve can be programmed more precisely for different aircraft weights and structures. |
Both systems perform the same operational job: accelerate a fully loaded aircraft to its calculated launch speed within the limited deck length. At the end of a steam launch, water brakes absorb the energy of the pistons; EMALS controls and stops its moving equipment electrically.
How is the correct catapult power calculated?
Catapult power is calculated from the aircraft’s required end speed and the conditions affecting that particular launch.
- Aircraft type and gross weight
- Wing, flap and external-store configuration
- Required launch speed
- Wind over the flight deck
- Ship speed and heading
- Catapult condition and operating limits
Wind over the deck matters because the aircraft needs airspeed, not merely speed relative to the ship. A carrier steaming into the wind provides useful airflow before the aircraft starts moving along the deck, reducing the additional deck-relative acceleration needed from the catapult.
Too little catapult energy is called a cold cat; the aircraft may leave the bow below its intended flying speed. Excessive energy produces a hot cat, imposing unnecessary acceleration and structural loads. Launch settings are independently checked because entering the wrong aircraft weight can create either condition.
Does the pilot pull back during a catapult launch?
The pilot follows the aircraft’s specific launch technique rather than making a normal runway rotation. Many carrier jets use predetermined take-off trim and assume the correct fly-away attitude as they clear the bow; other aircraft require carefully timed control input.
Pulling back aggressively while still attached can over-rotate the aircraft or risk a tail strike. Propeller-driven carrier aircraft and jets also differ, so a procedure learnt for one type should not be applied automatically to another. Once the catapult stroke begins, there is no normal pilot-controlled abort; an engine failure or other serious problem is handled under the aircraft’s emergency procedure.
Do all aircraft carriers use catapults?
Only carriers configured for catapult-assisted take-off use them. CATOBAR carriers combine catapults with arrested recovery, while STOBAR ships use a ski-jump for take-off and arresting gear for landing. STOVL carriers support aircraft capable of short take-offs and vertical landings.
A ski-jump changes the aircraft’s flight path but does not provide the powerful mechanical acceleration of a catapult. This is why carrier design, aircraft design and launch method must be compatible.
How are carrier catapults represented in flight simulators?
In a flight simulator, a visible carrier and a functioning catapult are separate features. Microsoft Flight Simulator users should first check how to identify carriers with usable launch systems, because many ship models are scenery objects without catapult logic.
DCS World models more of the aircraft-specific deck interaction on supported carrier modules; our DCS carrier launch procedure explains launch-bar engagement, power-up and launch signalling. In FSX Acceleration, the controls and required positioning differ, so use the specific FSX catapult setup and launch steps rather than assuming the real-world sequence is reproduced automatically.