MM21 - The Ross-Drive engine

Technical details
Year of construction 2002
Power piston stroke 14 mm
  diameter 12 mm
Displacer piston stroke 14 mm
  diameter 19,5 mm
Flywheel  diameter 64 mm
  material PMMA
Idle speed 600 rpm
Energy source alcohol
Mass 300 g 


This engine was made after the pattern of MM05, but smaller by a third. By using accordingly smaller DURAN test tubes and matching sectional aluminium as well as PMMA for the chassis it was possible to build a small transparent and smoothly running engine, of which I made two, one being sold at Ebay.