Editing Jet engine (section)

===Hybrid===
Combined-cycle engines simultaneously use two or more different principles of jet propulsion.
{| class="wikitable"
|-
!'''Type'''
!'''Description'''
!'''Advantages'''
!'''Disadvantages'''
|-
![[Air turborocket|Turborocket]]
|A turbojet where an additional [[oxidizer]] such as [[oxygen]] is added to the airstream to increase maximum altitude
|Very close to existing designs, operates in very high altitude, wide range of altitude and airspeed
|Airspeed limited to same range as turbojet engine, carrying oxidizer like [[LOX]] can be dangerous. Much heavier than simple rockets.
|-
![[Air-augmented rocket]]
|Essentially a ramjet where intake air is compressed and burnt with the exhaust from a rocket
|Mach 0 to Mach 4.5+ (can also run exoatmospheric), good efficiency at Mach 2 to 4
|Similar efficiency to rockets at low speed or exoatmospheric, inlet difficulties, a relatively undeveloped and unexplored type, cooling difficulties, very noisy, thrust/weight ratio is similar to ramjets.
|-
![[Precooled jet engine|Precooled jets]] / [[Liquid air cycle engine|LACE]]
|Intake air is chilled to very low temperatures at inlet in a heat exchanger before passing through a ramjet and/or turbojet and/or rocket engine.
|Easily tested on ground. Very high thrust/weight ratios are possible (~14) together with good fuel efficiency over a wide range of airspeeds, Mach 0–5.5+; this combination of efficiencies may permit launching to orbit, single stage, or very rapid, very long distance intercontinental travel.
|Exists only at the lab prototyping stage. Examples include [[RB545]], [[Reaction Engines SABRE]], [[ATREX]]. Requires liquid hydrogen fuel which has very low density and requires heavily insulated tankage.
|}