Editing Piston (section)

====Slipper pistons====
[[File:Ricardo slipper piston (Autocar Handbook, 13th ed, 1935).jpg|thumb|upright|Slipper piston]]
A '''slipper piston''' is a piston for a petrol engine that has been reduced in size and weight as much as possible. In the extreme case, they are reduced to the piston crown, support for the piston rings, and just enough of the piston skirt remaining to leave two lands so as to stop the piston rocking in the bore. The sides of the piston skirt around the gudgeon pin are reduced away from the cylinder wall. The purpose is mostly to reduce the reciprocating mass, thus making it easier to balance the engine and so permit high speeds.{{sfnp|Ricardo|1922|page=149}} In racing applications, slipper piston skirts can be configured to yield extremely light weight while maintaining the rigidity and strength of a full skirt.<ref>{{Citation|title=Piston with improved side loading resistance|date=2009-10-12|url=https://patents.google.com/patent/US20100089358A1/en|access-date=2018-04-22}}</ref>  Reduced inertia also improves mechanical efficiency of the engine: the forces required to accelerate and decelerate the reciprocating parts cause more piston friction with the cylinder wall than the fluid pressure on the piston head.{{sfnp|Ricardo|1922|pages=119–120, 122}} A secondary benefit may be some reduction in friction with the cylinder wall, since the area of the skirt, which slides up and down in the cylinder is reduced by half. However, most friction is due to the [[piston rings]], which are the parts which actually fit the tightest in the bore and the bearing surfaces of the wrist pin, and thus the benefit is reduced.

{{Commons category-inline|Slipper pistons}}