It appears that the Russians have made a significant advance in pulse-detonation engines (PDE).

A PDE is similar in concept to the pulse jet that powered the V1.

The differences are as follows:

• No Moving Parts (pulse jets have shutters)
• The flame front propogates through detonation as opposed to detonation (it’s a supersonic shock)
• It promises higher efficiencies that existing propulsion.
• It can operate from a stand still.

Here is the cycle for the engine: