<br><font size=2 face="sans-serif">Concerns of the Reverse Avalanche damaging planes is real, but do not think that fatigue plays a role here. Composites or either good or broken, and in the case of our planes, the damage is usually easy to see. As far as the CF wing tube and the fuse go, if you do X amounts of snaps, it does not weaken the structure with every snap, unless something is indeed already broken. Look for the signs of cracked glue joints and paint.<br>
The situation that would scare me are the planes that use styrofoam as a core material. Core sturctures work great for our planes because a 2mm thick core structure give an "apparent" stiffness equal to the modulus of a solid laminate of equal thickness without all the weight. Stiffness equates into a solid feeling-flying plane. This core structure, while having a near stiffness of the solid laminate by no means has the strength, and is in fact much weaker. To make matters worse, soft cores such as the styrofoam will buckle, and the core integrity is gone and so is the structural ridgidity, which means a flex, and possible structural failure. Such a problem would most likely show up as a chip of paint comming off the fuselage.</font>
<br><font size=2 face="sans-serif">The bending of an Aluminum wing tube shows the yield strength not the failure strength of the aluminum has been exceeded. CF tubes have no yield strength only a failure strength which is higher than the aluminum. CF wing tubes if exceeded in strength will go from perfectly good to simply broken. This will happen only once, not gradually, and that one time is the moment the strength is exceeded.<br>
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Gray Fowler<br>
Principal Chemical Engineer<br>
Composites Engineering</font>