This wooden air engine is powered by hand using a large hand pump.
The basic concept of a reciprocating movement changed into rotary motion or rotary motion into reciprocating motion can be traced back to the Roman empire or perhaps even earlier.
The same basic principles are used in today's modern engine where expanding gas is used to drive a piston and a crank is used to convert the movement into rotary motion.
The idea of a flywheel is used to overcome the positions where little or no torque is applied to the crank, the flywheel keeps it moving due to it's moment of Inertia.
This hand powered engine is used as a demonstration of these principles and does require a little practice to get the rhythm and timing right.