Hi Guys Recently I have started a new hobby into RC planes. What I have noticed is extensive use of Carbon composites weight yet sturdy structures. Now the problem is that these structures seem to be cut (milling/drilling/laser cutting/water jet cutting) from a sheet (or laminates) of carbon composites. Here are the problems: Don't carbon composites have very bad wear properties. If nuts are too tightened , they not only tend to scratch the material but the laminate also often cracks. I have seen lots of immature hobbyists due that. There is often not enough material between the holes and the edge, ie critical holes for attachment are too close to the edge of the component. There does not seem to be enough fibre to support in-plane loads around the hole There are often slots in the components to reduce weight (topology optimization?). They seem to be machined later into the sheet rather being included in the original manufacturing. I am assuming they either buy off the shelf prepeg sheets and cut them as and when required. Shouldn't a better practice be to incorporate in the holes/slots directly in the original manufacturing method (say making a proper mold for hand layup or vacuum bagging instead and avoid machining altogether). I understand, hobbies don't require such detailed engineering and need to be cost effective, but I want to know how a professional would do it? Here are some of opinions on the same, kindly correct me where ever I am off the track. Composite ideally should not be joined by bolts. In cases bolts seem the most economical option, at least washers should be used to redistribute the loading over a larger area? Holes near edges is poor design. There is should be enough material ( in terms of number effective load carrying fibres ) around a hole/slot. Is there any empirical relation for that (both for woven and single direction fibres). Or do we just use appropriate stress concentration factors as we do with most metals? Any tips on incorporating the slots/holes in the original composite manufacturing process, rather than machining them later (irrespective of how complicate the mold might become). Looking forward to suggestions from you guys.