{| |} The C-type blimp was a patrol airship developed by the US Navy shortly after World War I, a systematic improvement upon the B-type which was very suitable for training, but of limited value for patrol work. Larger, with two motors, and a longer endurance. Once again, the envelope production was split between Goodyear and Goodrich, with control cars being built by the Burgess division of Curtiss Aeroplane and Motor Company, and the St. Louis Aircraft Corporation. All ten of the "C" type blimps were delivered in late 1918, and examples served at all of the Navy's airship stations in 1919 and 1920. In 1921 the C-7 was the first airship ever to be inflated with helium. The Navy deflated its last two C-type airships, the C-7 and C-9 in 1922.