Two models in wood of Maudslay's rotary engine

Two models in wood of Joseph Maudslay's rotary engine, 1852

These wooden models represent the rotary engine patented by Joseph Maudslay in 1852; the same thing had, however, been patented by John Trotter in 1805. The engine consists essentially of a rotating cylindrical chamber, within which rotates a smaller cylindrical chamber placed eccentrically so as to touch the first. The inner chamber has a slot at one point, through which projects a radial partition fixed to the outer chamber; the crescent-shaped space between the two chambers is thus divided into two parts, one of which is expanding while the other is contracting, as the chambers revolve. Steam being admitted through a port in the outer chamber causes an unbalanced pressure upon the partition, the opposite side of which is connected with the exhaust by a port in the inner chamber, and so drives the chambers round. One model has the two chambers surrounded by a concentric casing to which the steam is admitted, the exhaust being through the axis. The other model is double and has three concentric rings with radial partitions between them, forming two chambers in which two eccentric rings rotate; no steam ports are shown on this model.