A small toy aircraft with an engine model of COX 049 and a piston about 11MM in diameter
The gap between the piston and the cylinder wall is large, and the piston ring is sealed with the cylinder wall
0. 25-0.8 this is not possible. It should be within 0.01 plus or minus
First of all, the piston is not round, and the side view is not square. This is due to thermal expansion at different parts of the piston in a high temperature environment.The local minimum gap of about 0.04, depending on the design, the smallest place probably in the piston to stop opening of the lower end of 15 to 20mm perpendicular to the piston pin position, of course not absolute, the design of the skirt length is not the same.The largest part of the gap is the fire bank, which is the place above the first ring, usually at 0,7~0.8mm
