Originally Posted by Windependence
Now that I think of it, didn't Don Stackhouse post somewhere about having devised an all wooden spar that rivaled the carbon capped ones in strength? I want to say he did.
Could be. It's sitting on top of the shelf in the corner at the moment. When we first designed the 3-meter Chrysalis, we planned to use carbon spar caps, since it was a given that the plane would have to tolerate winch launching. In an open class ship like this, I figure that means dealing with 300 pounds of winch line tension. However, after doing most of the engineering work for that, we discovered that there was a worldwide shortage of carbon (the French had bought it all for that new super-widebody airliner of theirs) and we could not hit our price targets.
So, back to the drawing board, this time with all wood, except for the joiners (the other given with a 3 meter is a two or three piece wing). The wing is still able to handle 300 pounds of line tension, is still thin for a wide speed range, but it's all wood. However, in spruce or something similar it would need to be nearly solid wood to have the required strength, so we did have to go to a different species. Even so, it still took a full box spar beefy enough that there is absolutely no need for leading edge sheeting.