Editing Air-augmented rocket (section)

==Variations==
===Shrouded rocket===
The simplest version of an air-augmentation system is found in the shrouded rocket. This consists largely of a rocket motor or motors positioned in a duct. The rocket exhaust entrains the air, pulling it through the duct, while also mixing with it and heating it, causing the pressure to increase downstream of the rocket. The resulting hot gas is then further expanded through an expanding nozzle.{{sfn|Brevig |1968|p=444}}

===Ducted rocket===
A slight variation on the shrouded rocket, the ducted rocket adds only a [[de Laval nozzle|convergent-divergent nozzle]]. This ensures the combustion takes place at subsonic speeds, improving the range of vehicle speeds where the system remains useful.{{sfn|Brevig |1968|p=444}}

===Ejector ramjet (et al)===
The ejector ramjet is a more complex system with potentially higher performance. Like the shrouded and ducted rocket, the system begins with a rocket engine(s) in an air intake. It differs in that the mixed exhaust enters a diffuser, slowing the speed of the airflow to subsonic speeds. Additional fuel is then injected, burning in this expanded section. The exhaust of that combustion then enters a convergent-divergent nozzle as in a conventional ramjet, or the ducted rocket case.{{sfn|Brevig |1968|p=444}}