The orbital family of ICE engine of 1972 has seen a lot of ongoing innovation and crossover variations with other rotary engines (like the Wankel) in past decad

The orbital family of ICE engine of 1972 has seen a lot of ongoing innovation and crossover variations with other rotary engines (like the Wankel) in past decades - such engine variants have had a major place in UAV (and other) drones. * https://en.wikipedia.org/wiki/Sarich_orbital_engine https://en.wikipedia.org/wiki/Sarich_orbital_engine * https://www.orbitaluav.com/ https://www.orbitaluav.com/ * https://www.aieuk.com/225acs-wankel-rotary-engine/ https://www.aieuk.com/225acs-wankel-rotary-engine/