Compressed air powered, 3 cylinder radial engine

This is a working 3 cylinder radial engine, powered by compressed air. It transforms potential energy stored in form of a pressurised air to kinetic energy in form of rotaty motion.

1. To fully build it you need:

• 608 ball bearing
• 8 x M4 16mm bolts
• 18 x M3 7mm (or even shorter) bolts

• 10 x M8 nut

  
  I also highly suggest that you use 400 grit sandpaper to smoothen the cylinder walls, mating surfaces between cylinders and the block and the disc valve or crankshaft if necessery.

2. When building focus on:

• really low friction when rotating - these engines are quite low on power so they may struggle to keep themselves running, especially on low pressures (I advise you also to use some kind of oil like prafin oil from pharmcay to further reduce friction and wear on the plastic parts)

• air tightness - it comes second in terms of importance because it comes with a cost of friction which is highly unwanted
   

  If you are unsure about something while constructing this engine please feel free to ask me any questions regarding the matter. I am eager to help out.

3. Principle of working: The engine relies on a rotating disc valve to operate. The valve redirects air through chanels to the cylinder where it pushes the piston down. The exhaust is executed by the ports in the cylinder walls which are fully uncovered at bottom dead center of the piston stroke. Then piston comes back up and the cycle repeats. There are 3 pistons which are 120 degrees out of phase thus they have 60 degrees of power stroke overlap. This should mean that the engine is self starting.