Where does combustion take place? Why the spring? It will just absorb the energy, and convert it to heat. Why?
How does the fuel/air fed to the system? Why a piston at all? Why not just a chamber or bucket of sorts, for the expanding gases to react against?
Why is the piston so small? How much energy transfer do you expect to get from such a small surface area?
How is this an improvement over a standard rotary engine?
The drawing is way to basic to make any kind of assessment.
I know, it was just a quick drawing I made. The entire unit rotates, and is housed in something else that has actual combustion chambers or compressed air feeds.
There is no way you can supply mechanical energy to the piston and compress it against the spring and NOT have the unit rotate on you.
That’s what it’s designed to do.
I think I’ve seen this befor...
http://www.halfbakery.com/