The Fritz-X was a German air-to-ground guided glide bomb, and was also known
as FX-l 400 or SD-1400.
It could be controlled during its drop by an observer in the parent aircraft
passing commands via a radio link. It was basically a 1400kg armor-piercing bomb
to which small wings and a tail unit containing the guidance mechanism had been
added. Signals received by the radio receiver in the bomb caused spoilers on the
tail surfaces to be raised into air stream, thus modifying the bomb's
Development began in 1939 and final trials were done in Italy in early 1942. Its
most notable success was the sinking of the Italian battleship Roma on 9
September 1943, which was achieved by hits with three Fritz-X bombs.