D-class blimp

The D class blimp was a patrol airship designed by the US Navy  in the early 1920s. The D-type blimps were slightly larger than the C-type and had many detail improvements. The Navy continued the practice of dividing the envelop production between Goodyear and Goodrich. The control cars were manufactured by the Naval Aircraft Factory. The major improvements were a better control car design. The engines were moved to the rear to reduce noise and allow better communications between crew members. The fuel tanks were suspended from the sides of the envelope. The envelope was identical to the C-type, except an additional six foot panel was inserted for a total length of 198 ft and a volume of 190000 cuft.

Operational history
The D-1 burned the day of its first flight in the Goodyear hangar at Wingfoot Lake, Ohio. The D-2, D-3, D-4 and D-5 were transferred to the United States Army which the Air Ship Board had given the primary role of operating non-rigid airships after World War I. D-1 participated as an observation and photography aircraft at the famed "Mitchell" bombing test of 1921. D-3 also participated in the Mitchell bombing trials, tested experimental mooring masts, D-3 also participated in early "hook-on" experiments to see if it was possible for an airplane to fly up to and hook onto a trapeze hanging from an airship. No actual hook-ons were achieved, but approaches were practiced. D-4 also participated in the Mitchell trials, and in observation jobs. The D-5 was never operated by the Army with that designation. After the loss of D-2, the D-5 was erected with more powerful 180 hp Wright V engines and flown as the D-2-2.

The Navy retained one additional D-type, the D-6. The D-6 was built by the Naval Aircraft Factory, Philadelphia, Pennsylvania, but her design was sufficiently different to separate her from the other five D-class airships. It featured a further improved control car (the "D-1 Enclosed Cabin Car) which had a water tight bottom for landings on water and internal fuel tanks. The D-6 was burned in the Naval Air Station Rockaway hangar fire of 31 August 1921 along with two small dirigibles, the C-10 and the H-1 and the kite balloon A-P.

The last operational D-type, the D-3 was apparently deflated by the Army in early 1924.

Operators

 * United States Navy
 * United States Navy