So, let's look at the diagram - this is the so-called speed characteristic of a pulse jet engine, the dependence of thrust (on the left) and specific fuel consumption (on the right) on the flight speed. The diagram was obtained in our program for two types of engines with the same pipe diameter - 140 mm, one valved, the second valveless.
What do we see? We see a complete disaster with the valveless engine.
1. Valveless engine thrust, all other things being equal, is 30% lower than valved.
2. With such low thrust, valveless engine has too much aerodynamic drag, also specific thrust falls down too quickly, and as a result of which this the engine thrust catastrophically falls with flight speed
.3. In fact, a valveless engine does not allow UAVs to fly at speeds over 400 km/h
4. At the same time, it has a catastrophically high specific fuel consumption, 20-30% higher than the fuel consumption of a valved engine.
5. On the contrary, a valved engine feels quite good even at speeds of 800-900 km/h, i.e. in 2 times more than valveless can get to, and still has an acceptable fuel consumption at these speeds.
Our conclusions are disappointing for fans of valveless engines:
1. Valveless engines are not suitable for high-speed UAVs at all.
2. It is unclear for what purpose the project of the WAVE Engine Corp. company was made.
3. Target projects like the Russian Enics E95 are poorly suited even for targets, because during short-term flights, artillerymen and missilemen may not have enough time to aim
.4. The main advantage of a valveless engine - the absence of valves - is not really an advantage, since the excessively high fuel consumption does not allow it to be implemented in practice.
5. In fact, a valveless engine is good mainly only for demonstration runs in your own garage - its use on aircraft is ineffective. That is, a valveless pipe is not an aircraft engine at all.
6. The valved engine made in Germany 80 years ago remains an unattainable leader in technology - German doctors and professors Diedrich, Gosslau, Zobel, Schulz-Grunow, as well as the inventor himself, Herr Schmidt, made a thing that no one has managed to surpass
.7. High-speed UAVs with a valved pulse jet engine can be quite real, but in the case of mass production only, by thousands of UAVs, in another case, for individual production, it is better to forget about pulsejets, they have no advantages over turbojet engines.
Something like that, in this context...
Unfortunately, our opinion is that anyone who tries to fit a valveless engine into a UAV doesn't really understand the principles of pulse jet engine working and only has a calculator, a cutter and a welder at their garage. We feel sorry for such "designers". We even suspect that the gentlemen from the WAVE Engine Corp. are the same...
What to do? We don't know...