F-104S "ASA" prototype 311°Gruppo during take-off at Decimomannu AB 1986

Based upon the CL-901 Lockheed concept the FIAT factory in Italy delevoped an improved version of the F-104G. The aircraft had modified inlets with extra doors to serve the needs of the more powerfull General Electric GE-19 engine. 
It had extra fins on its aft fuselage to improve the stability in flight and it was capable of firing the more modern Sparrow radar-guided missiles using the new adopted NASARR R-21G/H radar 
which has moving-target indication and tracking capability. More sophistated avionics made the S complete. The "S" was choosen for the capability of carrying the Sparrow missiles. 
In total 246 aircraft were manufactured and two F-104Gs were modified to F-104S prototype. 

"Aux Air Doors": these doors are located on each inlet duct. The doors are opened only during takeoff to provide an increased air supply to the engine for added thrust.

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