ORIGINAL: JPMacG

Reading through this thread made me curious about the amount of thermal expansion we really might encounter using a plastic push rod. I did some homework and came up with the following:

Assume the pushrod is 30 inches long (typical for a 40 sized plane)
Assume there is a 30 degree F increase in temperature

The CTE of plastic varies widely with the type of plastic. The lowest I found was 15 parts per million per degree F (for polyimide) and the highest was 110 ppm per deg F (for polypropylene).

Doing the arithmetic, the pushrod would grow in length about 0.1 inch for the high-CTE plastic and about 0.01 inch for the low-CTE plastic.