From appendix 6: We are not talking exactly about the formula ramjet rocket that is widespread in small and medium missiles.

-It is a combination of turbo and ramjet, or AirTurbo-Ramjet.

-Exhaust gases are directed to a peripheral fan turbine, which first allows operation at low speed, and then at high speed in ramjet mode.

-The diagram below is a heat exchanger (also called regenerative system).

-The figure is obtained from the Flight Magazine, though the manufacturer is not mentioned.

“ATR diagram” (PiP)

It is planned for supersonic speeds, being a step beyond the VCE (see) and before the Scramjets.

"Dibujo de un turbo-cohete hipersónico”"

-It can take off and land horizontally from the ground. Below we have a cutaway drawing of two of them, being the lower one with the short nozzle for lower altitudes, and the upper one with the long nozzle for higher altitudes.

-In the 1990s, several options have been considered to reach such high speeds, in excess of Mach 6 and above.

"Two formulas for supersonic flight"

-First we have the ramjet, and below it the turbofan ramjet.

“Two more engine models”

-Following the turbo-ramjet and the concept of turbo-expander-ramjet.

-And now we continue with a rocket that has the air increased with liquid air.

"Rocket that has the air increased with liquid air"