Advanced Short Take-Off/Vertical Landing (ASTOVL) 1983-1994
The Defense Advanced Research Projects Agency (DARPA) began a program in 1983 to begin looking at the technologies available to design and manufacture a follow-on supersonic replace for the AV-8 Harrier. The program, known as ASTOVL, would eventually lead become a joint U.S.-U.K. collaboration.
The Advanced Short Takeoff Vertical Landing (ASTOVL) Program started as a joint research and technology effort in 1983 between the US DoD and the UK Ministry of Defense (MoD). Its aim was to support the eventual development of a supersonic STOVL strike fighter. Four powered lift concepts were selected for initial study, and preliminary assessments were performed in 1985. Further studies indicated that none of the original four concepts were completely suitable. However with the projected thrust available from the F-119 engine then in advanced development, two revised evolutions of these four concepts showed significant promise. These were the Shaft Driven Lift Fan (SDLF) and the Gas Coupled Lift Fan (GCLF).
In 1987 the results of the ASTOVL program made clear that the technologies available were not yet advanced enough to generate a replacement that the US and UK would have been satisfied with. At this time, DARPA secretly approached the Lockheed Skunk Works in the hopes that they would be able to develop an aircraft like they had hoped would have appeared from the first phase of ASTOVL. Lockheed told DARPA that they had some ideas that could be matured and that, if they were successful would meet the goals that DARPA was trying to achieve. At the same time, DARPA continued with ASTOVL Phase II as a cover for the covert work being done at the Skunk Works. In 1988, the ASTOVL program came under DARPA control as a result of the Nunn-Quayle Research and Development Initiative to fund cooperative efforts between the U.S. and NATO allies.
When the original ASTOVL agreement between the US and UK expired in 1991, the international program officially ended. However, discussion of a follow-on collaborative technology maturation and demonstration program with the UK continued. In parallel, the airframe and engine companies continued their design efforts while DARPA and the Navy worked to establish a development program. These design efforts were focused on a STOVL Strike Fighter, "Desired Operational Capabilities", document signed by the Department of the Navy in February 1988. Initial efforts had been focused on developing a STOVL Strike Fighter for the Marine Corps, however a major finding in the study efforts was that by replacing the STOVL propulsive lift apparatus with additional fuel tanking, a highly capable F-16 class Air Force variant could be attained. This would result in a highly common aircraft and eliminate many of the challenges typically associated with developing a common Navy/Air Force aircraft since the structural requirements of a STOVL aircraft are much more similar to an Air Force aircraft than a Navy catapult/arresting gear aircraft.
Hence a revised DARPA/U.S. Navy ASTOVL Program was formulated in early 1992 with the aim of demonstrating an affordable STOVL strike fighter for the U.S. Marine Corps with a Conventional Takeoff and Landing (CTOL) variant for possible U.S. Air Force service. With this new emphasis, the program adopted the name Common Affordable Lightweight Fighter (CALF).
|Join the GlobalSecurity.org mailing list|