By changing the stroke length or the pump rate the production rate can be changed.
The stroke length is determined by the cranks on the crankshaft.
The amount of air in the system, or lack of it, is adjustable and determines the stroke length.
The user can then set the stroke length and the stroke speed to his personal preference.
The relative proportion of offset distance vs. stroke length ranges from very small to almost 20%; viz.
Because of those factors, single acting cylinders are recommended for applications that require no more than 100mm of stroke length.
This was not a "completely new engine", however: the stroke length of 68.5 mm remained unchanged as did the 2-stroke 4-cylinder configuration.
The stroke length on both cylinders was 21 inches.
The pistons are usually less than half an inch (13 mm) in diameter with similar stroke lengths.
As before, the stroke length was fixed at 69.8 mm: differences in engine size were achieved by varying the cylinder bore.