Im thinking about using Doug Fir for my Air Camper. If Doug Fir is stronger can I reduce the woods cross sectional dimension?
Yes you could, but you need to know the engineering behind this to do it right. Also, once you go through all the calculations and effort, you are only going to save about 10 pounds. Personally, I think it would be easier to shave 10 pounds off the pilots weight than to try to save 10 pounds re-engineering the plane. Steve Eldredges Doug Fir Air Camper is lighter than some of the all spruce Air Campers, and as far as I know, he built his to the dimensions shown on the plans.