High Quality Content by WIKIPEDIA articles! The F-1 is a rocket engine developed by Rocketdyne and used in the Saturn V. Five F-1 engines were used in the S-IC first stage of each Saturn V, which served as the main launch vehicle in the Apollo program. The F-1 is still the most powerful single-chamber liquid-fueled rocket engine ever developed. The RD-170 has slightly more thrust, using a cluster of four smaller combustion chambers and nozzles.