Title: " While composite props are making inroads, the century-old technology of wood more than holds its own. "
http://www.avweb.com/news/features/Wooden-Props-226059-1.html
Here are three excerpts I have cut and pasted. Hit the link for the complete story. I had no idea UAVs were so heavily into wood. Seems lately I have had no idea about a lot of things .
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More than a century after the Wrights carved their paddles out of select spruce and while composites continue to make strides, wood as a prop material is, if not enjoying a resurgence, at least holding its own in the propeller market. Surprisingly, if it weren't for carefully crafted birch props, more than a few edge-of-tech UAVs would be beached.
"Metal props are basically high materials costs and lower labor costs. You have a forging and that's a significant investment in forging dies," he explains. "For a wood prop, the materials costs are relatively low. But there's a very high labor cost. Composites are exactly between the two; lower labor costs than wood, but higher than metal. For composites, materials cost is not a key driver.
Wood excels in two other characteristics. "A wood prop naturally damps harmonics. It eats them up and dissipates them. A metal prop is like a tuning fork, it takes a harmonic and really enhances it and you can feel that back in the airframe. A composite prop, again, is in the middle. It doesn't damp as well as wood, but it doesn't enhance harmonics like a metal prop does,"
