I just love this plane to death, I'm on my 3rd (no don't ask, it flys so well it makes me cocky. My current one I got about 6 months ago, and I believe it has World's new covering. I say this because it is a bit more grainy than the other versions I had. Seems a lot thinner and more prone to tears also. One "problem" I'm having with this new stuff is that it seems to absorb fuel and cause a stain. Started where the hinges were put in, around the horns, around the landing gear blocks and small pin holes caused by rocks etc. Now the staining has started in the top of the wing where there are no holes. I'm begining to get concerned about fuel causing the balsa to weaken. Has anyone else experienced this?