The F-16 Block 30 fighter was equipped with a diverterless supersonic inlet, which took the place of the aircraft’s original intake diverter
The F-16 Fighting Falcon, which has been the cornerstone of the US Air Force’s (USAF) fighter force for more than 30 years, has played a significant role in maintaining air superiority. The F-16, which originated from a competition in 1972 that demanded a lightweight, highly maneuverable fighter jet, emerged victorious and went into production in the same year. An agreement to form a consortium between the United States and the four NATO members—Belgium, Denmark, the Netherlands, and Norway—was a component of its original manufacture. From then on, the F-16 changed from being a day fighter with air superiority to an all-weather, multirole aircraft that is still in service today all over the world.
A diverterless supersonic inlet, or DSI, was even added to an F-16 as part of the Joint Strike Fighter (JSF) program, which is now the F-35 Lightning II. According to Code One Magazine, the inlet bump functions in conjunction with the forward-swept inlet cowl to reroute undesired boundary layer airflow away from the inlet at high aircraft speeds during supersonic flight. This effectively performs the function of heavier, more intricate, and more expensive diverters that are employed by a number of modern fighter aircraft. Twelve flights were conducted over nine days in December 1996 as part of the flight test program.
Lockheed Martin conducted the DSI’s first research in the early 1990s. On December 11, 1996, the first Lockheed DSI was flown as a part of a project called Technology Demonstration. It was mounted on an F-16 Block 30 fighter, taking the place of the original intake diverter on the aircraft. The modified F-16 had handling qualities akin to a regular F-16 and a top speed of Mach 2.0, which is the F-16’s clean approved maximum speed. It was also shown that subsonic specific excess power was slightly improved.
In mid-1994, the DSI idea was included as a trade study item to the Joint Advanced Strike Technology (JAST, subsequently renamed JSF) program. It was compared to a traditional “caret”-style intake. Subsequently, a DSI was integrated into the Lockheed Martin F-35 Lightning II’s design, as it demonstrated superior performance while being 30% lighter and requiring less production and maintenance than conventional inlets.
Conventional aircraft inlets have a large number of heavy-moving parts. As opposed to previous diverter-plate inlets, DSI removes all moving parts, making it significantly less complex and more dependable. The aircraft’s total weight is also decreased by the reduction of moving parts.
By removing radar reflections between the aircraft’s skin and diverter, DSIs also significantly enhance the very-low-observable characteristics of the aircraft. Furthermore, because the “bump” surface offers an extra layer of protection for the engine fans against radar waves, it lessens the engine’s exposure to radar, hence lowering a substantial source of radar reflection. According to analysts, the DSI lessens the requirement for using radar-absorbent materials (RAMs).
Photo by Lockheed Martin