Jet engines are relatively simple in their basic design, but advancements in gas turbine engine technology have mostly done away with the cool-looking bucket-type reverse thrust systems. These thrust mechanisms used to be on most jet engines, but thanks to newer, more efficient engine designs they are no longer commonly used in commercial jets, though some private jets with smaller and cheaper engines still use them. Two halves of the “bucket” hydraulically transition from shielding the exterior of the turbine engine to clamping together behind the turbine, which redirects the jet wash and slows the forward motion of the plane once it has landed.
Most modern commercial jet engines have a cold section that encircles the entire combustion chamber in a jacket of cool air to increase efficiency. This advanced design allows for a more subtle reverse thrust mechanism where flaps lift on the sides of the turbine, redirecting the cool air forward, thus decreasing the plane’s forward momentum. Bucket-type reverse thrusters look much more dramatic in their operation, and thus are way cooler to watch.
Reverse thrust doesn’t actually reverse the direction of the jet engine’s rotation as that would be incredibly mechanically taxing and realistically infeasible. Engaging reverse thrust just involves deflecting the flow of the jet wash. Effectively, it reverses the rearward flow of air that normally pushes the plane forward, and instead directs the thrust forward in the opposite direction of travel, slowing the plane down.
If you’ve ever flown commercially, you know that as soon as the plane touches down on the runway, the engines get significantly louder. That sudden volume increase is caused by engaging reverse thrust. Reverse thrust creates a lot of noise because the jet engine suddenly switches from moving with the flow of air, to redirecting the extremely high-speed jet wash forward against the direction of travel, and forcing it into oncoming air. This sudden change of airflow causes the loud wind noise when reverse thrust is engaged. Next time you’re plane spotting, keep an eye out for small private jets engaging their oh-so-retro bucket-type reverse thrust mechanisms.
