Abstract: An improved combustion engine, compressor, pump, or fluid driven motor in single cylinder (20 of FIG. 1) or multiple cylinder (20 of FIG. 13), versions wherein a normally cylindrical rotor (50) external to drive or driven bearings (64, 65, 65A, 65B), has a patterned cam track (between 52 and 53) for transforming the piston (32) linear reciprocating motion to rotary motion. Two cam tracks (52, 53) can be offset coaxially to allow for continuous unidirectional rotation of said bearings.

Abstract: Airship tail fins (20) deflect under excessive load on axii (108,110) to protect the airship hull (22) and also reduce angles of attack to disturbing airflow. A propulsion engine (24) may be mounted to the tail fin structure. A longitudinally elongated roller (36) may be mounted to the lower tail fin to act as landing gear. Two widely separated lower tail fins may control pitch and roll when moored by providing secure attachment points, as at shaft (38), for ground handling.