11. During his time there, thousands of free-piston engines had been sold. 12. The aircraft is powered by a modified Continental O-200 piston engine . 13. Today, most general aviation piston engine powered aircraft are naturally aspirated. 14. It is powered by an air-cooled piston engine driving a fixed pitch propeller. 15. Thus the 1975 Chevrolet Monza was launched carrying a conventional piston engine instead. 16. The first successful application of the free-piston engine concept was as air compressors. 17. Jet engines were taking over from piston engines in the air. 18. The free-piston engine was patented in 1934 by Raul Pateras Pescara. 19. The aircraft was powered by two wing mounted Avco Lycoming turbocharged piston engines . 20. Mechanically, gas turbines can be considerably less complex than internal combustion piston engines .
