turbojet

At lower speeds, the turbojet provided most of the compression and most of the energy from fuel combustion.

Ramjets can't operate at slow speed therefore it uses a turbojet design to get it going.

For turbojet engines altitudes of about 40 km appear to be possible, whereas for ramjet engines 55 km may be achievable.

It's not quite the same as the SR-71 Blackbird engine which is a turbojet engine that morphs mid-flight into a ramjet.

Then at high speed, the J-58 transitions from a turbojet to a functional ramjet.

A thrust-to-weight ratio of 10:1 is impressive, but not out of line with what you'd expect to see from a full-sized turbojet.

Given that it's turbojet powered, that missile is almost certainly subsonic and better suited for taking out prop-driven drones like the Predator.

Of course, could also have a turbine, that is, with little blades like in a turbojet engine -- these tend to be expensive.

TurboJET in Hong Kong use Boeing hydrofoils (Jetfoil) between HK and Macau [1][2].

At higher speeds, the turbojet largely ceased to provide thrust; instead, air was compressed by the shock cones and fuel burned in the afterburner.

Similarly, in 1930, Frank Whittle patented the turbojet.

> A unique hybrid, the engine can be thought of as a turbojet inside a ramjet.

This was due to the "turbojet-assisted ramjet" design of the Pratt and Whitney J-58.

From that link, "the system delivers 10% more thrust [...] than a small turbojet." They are still very deeply limited by compressor technology, regardless of whether they use combustion or electric propulsion.

Turbojet only become efficient over Mach 1.