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Marek S-Hayward Marble Mantis


This is an interesting variation on the Stirling engine, which uses three glass marbles as the displacer. It's also unusual in that it uses a ratchet mechanism instead of a crank to convert the linear motion of the power piston into circular motion of the driving wheel.

A glass test tube forms the displacement cylinder and also encloses the power cylinder. The power cylinder consists of a small free moving syringe. The rear end of the tube is heated by a single wick meths burner. The heated air expands and pushes the power piston forward. As the power piston travels forward, the piston rod rides up over the ratchet wheel, causing the displacement cylinder to tilt upwards at the front. This allows the three marbles to roll back towards the rear end, displacing the enclosed air forward into the cold part of the tube. As the air cools, the power piston retracts, causing the tube to tilt in the other direction and the marbles to roll back down towards the rear, displacing the air back into the hot part.

The model was purchased as a kit and assembled by me.

Make Marek S-Hayward
Model Marble Mantis
Made 2019
Description Marble Stirling engine tricycle
Cylinders 1
Cylinder Type Glass syringe
Bore mm 9.5
Stroke mm 30
Mechanical Condition Good
Cosmetic Condition Good
Paintwork N/A
Purchased 11 April 2019
Purchase cost 34.99
Additional cost