Propulsion System Classification

Classification and operating principles of air-breathing engines (variants of gas turbines and ramjets) and non-air-breathing engines (chemical-, electric-, and nuclear-rockets) are discussed in this chapter. \(\bullet \) How the suitability of air-breathing engines for different flight ranges—subsonic to hypersonic—changes from turboshaft to scramjet is addressed. \(\bullet \) Merits and demerits of solid-, liquid-, and hybrid-rockets are discussed. Compared to solid rockets, liquid engines find wider applications. \(\bullet \) Most electric rockets, contrary to chemical ones, are of unlimited energy but limited by power. And, this makes them suitable for interplanetary travel and beyond. Working principles of resistojets, arcjets, ion engines, and Hall-, pulsed-plasma-, magneto-plasmadynamic-, and pulsed-inductive-thrusters are explained. Features of flight-proven electric thrusters are tabled. \(\bullet \) For interplanetary travel and beyond by humans, a relatively large power with unlimited energy through nuclear propulsion is the requirement. \(\bullet \) Number of concept questions and numerical problems with answers are included at the chapter end.