Since Türkiye's twin-engine UCAVs (in development) will hit supersonic speeds, would it make sense to implement Divertless Supersonic inlet (DSI)?
Diverterless Supersonic Inlet with its ugly bump is an ingenious invention of an Italian scientist, Antonio Ferri in the 1950s. However it could not be exploited to the full then, due to the lack of computer power to implement it fully, through Computational Fluid Dynamics.
It solves the unwanted interference of boundary layer airflow problems without any moving parts and imparts low RCS characteristics to the plane by hiding the fanblades of the engine.
If you check the intake of f22, it uses a serpentine shaped ramp intake, that has a gap between the fuselage and the inlet to stop the boundary layer airflow to impede with inlet’s airflow.
But if you look at the YF35’s DSI set up, it has a bump to deflect and decrease supersonic air flow speed to give controlled air pressure to the compressors.
The function of the air intake is mainly to prevent boundary layer ingestion and pressure recovery across various angles of attack. They accomplish this feat by separating the turbulent boundary layer of the fuselage from the air entering the compressor via different means and they control the location of shock waves formed in them.
The DSI achieves this with more than 95% efficiency.
There are however certain limitations; because the DSI has no moving parts and they provide most efficient pressure recovery only at a particular Mach numbers, usually between Mach 1-2. The efficiency decreases with both positive and negative deviation from the sweet spot. Therefore, an intake with a mobile device such as a cone or a ramp can be efficient at larger range of Mach as they can mechanically move the mobile devices to control the position of the shock wave.
Since modern fighters are not limited by speed/ thrust and rather emphasise on low observability, it is not surprising that we are now seeing the DSI application in a variety of combat platforms more and more.