Ever wondered why engine noise gets louder on touchdown at an airport?
Aircraft thrust reversers are systems designed to redirect the exhaust airflow of gas turbine engines forward upon landing, providing additional deceleration during the landing rollout. Essentially, they rotate the direction of the engine thrust without having to rotate the entire engine 180 degrees, helping to slow the aircraft after it touches down on the runway. As a passenger, you will most likely notice a noise that sounds like an increase in thrust but is actually the exhaust being redirected forwards.
Thrust reversers enhance an aircraft’s braking efficiency, particularly during landing on relatively short runways or in adverse weather conditions. By deploying the reversers on touchdown, you can reduce the reliance on the aircraft’s wheel brakes at higher speeds after touchdown. In addition to reversers and wheel brakes, ground spoilers are deployed to ‘dump lift’, and effectively secure the aircraft on the runway. Whilst it’s not required to use reverse thrust in some circumstances, most large passenger aircraft will deploy it on landing.
What do thrust reversers look like?
Thrust reversers can take a variety of forms, but some are far more common. Let’s take a look at the main designs of reverse thrust systems found on commercial and private aircraft.
1. Clamshell reversers – officially called ‘Target-Type Reversers’ these are simple, hinged doors or clamshell-like structures that cover the rear section of the engine exhaust nozzle. When deployed, they redirect the exhaust gasses forward, generating the reverse thrust. This design is most commonly seen on early large passenger jets and business aircraft.
2. Cascade Thrust Reversers – also known as ‘bucket’ reversers, these use a series of blocker doors that extend into the exhaust stream, diverting the airflow forwards. These are commonly found on high bypass turbofan engines, so they are the design you…