its's good to hear, there is still interest on these items.
@ metiz: PDE means Pulse Detonation Engine - that are detonation pulses, no continuous run
...but no kidding, you are right, pulse rate can be increased from now 1.4Hz to about 5...10 Hz by using high pressure gas injection and high speed spolenoid valves (or piezo valves). That would be next development step.