1930(Neptun L 9)
- Designation: R101
- Dimensions: 777 x 131 ft.
- Gas Volume: 5.5 million cu. ft. of hydrogen
- Engines: 5 Beardmore MkI Tornado 8 cylinder 585 bhp diesel engines = 71 mph
- Crew: 42
- Builder: Royal Airship Works, Cardington, Bedfordshire
- First flight: 1 Oct 1930
- Service: Originally designed at a length of 735 ft., with 4.9 million cu. ft. of volume. On completion, she was the largest airship to date. Her net lift was disappointing, however, so she was cut in half and an extra bay added, increasing her length and volume significantly. Crashed near Beauvais, France 5 Oct 1930, while on a flight from London to Calcutta; 48 out of 54 passengers and crew were killed, including Lord Thompson, Secretary for Air. This disaster effectively killed British rigid airship development.