Why do standard aircraft cylinder oversizes range from 0.010 inch to 0.030 inch?

The reason standard aircraft cylinder oversizes range from 0.010 inch to 0.030 inch primarily relates to the design and performance characteristics of the cylinders. Aircraft engine cylinders often have relatively thin walls, and this geometry must be managed carefully to ensure structural integrity and effective heat dissipation.

When cylinders are oversized beyond a certain dimension, their walls become thinner, which can negatively impact their ability to withstand the pressures and temperatures typical of aircraft operations. Nitriding is a heat treatment process often applied to enhance the surface hardness and wear resistance of the cylinder walls, but it is not a substitute for adequate wall thickness.

The specific oversize ranges allow for sufficient material removal to restore cylinder surfaces to serviceable conditions after wear or damage while still maintaining structural integrity and performance. These ranges are thus carefully chosen to balance durability and operational effectiveness while providing enough leeway for machining.

This context highlights why the choice related to the walls being relatively thin and the potential for nitriding is the best answer, as it directly addresses the physical design characteristics that dictate the acceptable oversize limits in aircraft cylinders.