A rotational engine system comprises a rotational engine and a propulsion system. The rotational engine includes an outer ring enclosure, an inner ring component, and a drive gear. The inner ring component includes a piston and a drive gear engagement portion. The piston is configured to travel within the outer ring enclosure along a circumference of the outer ring enclosure. The drive gear engagement portion is configured to rotate as the piston travels along the circumference of the circular shape of the outer ring enclosure. The drive gear is coupled to the drive gear engagement portion of the inner ring component such that rotation of the drive gear engagement portion rotationally drives the drive gear. The propulsion system is configured to deliver propulsive energy to propel the piston along the circumference of the outer ring enclosure.