A model "Heinrici" hot air engine built to the Edgar Westbury design written up in "Model Engineer". I had a similar one in last year, there's a clip of that one running here in case you've forgotten what they sound like running (pretty much silent actually). This one is water-cooled as per Westbury's instructions and has been equipped with a neatly-done gas burner, complete with hose and fitting for one of the commercially available "camping gas" canisters.
Height 21 1/2 inches
Flywheel 6 inch diameter