A manned prototype, the SPAS-4 demonstrator (C-FRLM, named ‘Face’) has a volume of 41,500 cu.ft. (1,180 cu.m.). It is a 43′ (13.1 m.) diameter sphere and seats the pilot and one passenger. The SPAS-4 airship is powered by two 50 hp. engines.
21st Century Airships SPAS-4
All Aero 