The Manson engine is a hot air engine that was first described by A. D. Manson in the March 1952 issue of Newnes Practical Mechanics-Magazines. Manson Engines can be started both ways (clockwise and anti-clockwise). It has a stepped piston. The front part is acting as a displacer and the back part as work piston (displacer and piston move as a single component). The engine only requires three moving parts (piston, piston rod and crank).
The engine is double acting, as it is using both the expansion of the warmed air and the contraction of cooling air to exploit work.
The engine has no commercial or practical application. The engines are built mainly as desk toys, physics demonstrations, and novelties.
^ abC2 DE 19904269 C2, Michael Ruppel, "Heißluftmotor - Heat engine has a simplified design with combined piston and valve and with alternate sides of the piston vented in either limits of the piston movement", published 2000-11-9, issued 2001-6-5
^GB application 2554458A, Christopher Guise, "Improvement to Manson engine", published 2000-11-09
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