F-35 Lightning II Joint Program Office

Diverterless Inlet

The F-35’s diverterless inlet lightens the overall weight of the aircraft. Traditional aircraft inlets were comprised of many moving parts and are much heavier than newer diverterless inlets. The diverterless inlet also eliminates all moving parts.

When an aircraft is flying, the speed of the air relative to the engine is equal to the plane’s flight speed. However, current turbine engines are unable to handle supersonic airflow. This is because shock waves associated with supersonic speeds can damage or cause dangerous vibrations in turbine blades, resulting in loss of thrust or engine failure.

Consequently, in aircraft travelling at supersonic speeds, the air entering the inlet must be slowed down to subsonic speeds before reaching the compressor and turbine blades of the jet engine. Additionally, the airflow must also be at the optimal speed and volume to achive maximum thrust.

The DSI bump design functions as a compression surface and creates a pressure distribution that prevents the majority of the boundary layer air from entering the inlet at speeds up to Mach 2. In essence, the DSI does away with complex and heavy mechanical systems.