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Warren (Staff) - 2/18/2020 11:03:52 AM

You will be surprised how much the curvature helps with stiffness.  A typical bonnet or boot skin, which is relatively flat, without a core may have 6 or 7 layers of a 210gsm cloth - less if an additional support frame or foam core is used.  Something like this you might be able to use less.  Perhaps a single layer of a 210gsm cloth on the surface, and then a couple of layers of 450gsm cloth to back up.  The 210gsm cloth is around 0.25mm thick and the 450gsm 0.5mm thick per layer so you would end up with something just over a mm thick.  With the double curvature that should certainly hold it's shape and have a nice bit of stiffness.  If it has a bit too much flex or twist, you could add some foam core material as Matt suggested above. 

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Matt (Staff) - 2/17/2020 8:08:15 AM

I'm not quite sure I understand what you mean by a better result? - Assuming you mean what would give the most strength in this area then there wouldn't be any different between multiple layers of woven carbon fibre tape and multiple layers of woven carbon fibre cloth, they're really just two different formats of the same thing. Therefore, given the large size of this 'lip' then I'd suggest that woven carbon fibre cloth would be the most practical way to reinforce this area.

The shape, size and way this panel is mounted might mean that it really doesn't need much by way of additional stiffness and certainly the convex dome-like shape will naturally be a strong shape anyway. If you did find that after making it as a single skin that needs some additional stiffness then you could always add some 3mm closed cell foam sandwiched underneath another layer of carbon fibre. This could be done after the main part was made and simply wet-laid on and then vacuum bagged down.