Dirigibles Exhibit
DAYTON, Ohio -- Dirigibles are of three types: non-rigid, semi-rigid and rigid. Non-rigid dirigibles, often called blimps, rely on the gas pressure in the envelope to maintain their shape. Semi-rigid dirigibles have a keel that runs along the bottom of the envelope. Rigid dirigibles have an internal structure inside the envelope. This exhibit in the Early Years Gallery at the National Museum of the United States Air Force shows models of the Giffard airship (non-rigid dirigible), the "La France" (semi-rigid dirigible), and the "Zeppelin LZ-1" (world's first rigid dirigible, first flown in 1900). (U.S. Air Force photo)