f17582d2_engine___Free_net_encyclopedia__Type
[Description] Intake air is compressed entirely by speed of oncoming air and duct shape (divergent) [Advantages] Very few moving parts, Mach 0.8 to Mach 5+, efficient at high speed (> Mach 2.0 or so), lightest of all airbreathing jets (thrust/weight ratio up to 30 at optimum speed) [Disadvantages] Must have a high initial speed to function, inherently inefficient at slow speeds due to poor compression ratio, difficult to arrange shaft power for accessories, difficult to engineer to be efficient over a wide range of airspeeds. [Type] 
Ramjet
Jet engine - Free net encyclopedia
Type