- The working principle is similar to the hot air engine, except that this engine draws hot air into the cylinder.
- Heat is drawn into the cylinder, at BDC the inlet valve shuts the heat then cools down this in turn creates a vacuum, this vacuum plus air pressure then forces the piston back up the bore which gives the power stroke. A constant burning flame is used to relight the gas after the main ignition flame has been sucked into the cylinder.
- Model Vacuum Engine by Mick Cherry.
- glue-it.com Model making website with club, shop and museum listings.