Op dinsdag 6 december 2016 11:58:23 UTC+1 schreef Ross:
I tend to disagree with most of that.
UD is difficult on complex shapes yes, but what is complex about a wing? It is basically straight. If you can laminate it with wet laminate, you can do it with prepreg.


Not really. Wing skins need 45/-45 fibers. Easy enough to put in a single tapered wing, but multiple tapers, fairings or wing tips are pretty awkward for either prepregs or thick BIAX/TRIAX.
Fuselage is worse.

Don't see the issue with postcure. No need for it to be done in the mold with Prepreg. We were postcuring suspension to 180-220 deg C out of the mold and had no issues. They were cured at 130 to start with.
As far as thermal expansion goes, why not make your molds out of tooling prepreg? Works like a charm, and if you have a decent glider you will make plenty of gliders out of the mold and you will always have the same shape. Beats having to rework your molds every couple of years
Pretty expensive to make such a mold since you need a plug that can withstand that temperature too. Solid aluminium requires major adjustment (thermal expansion during cure), inconel is $$$.
That's one of the biggest advantages of infusion. Cure at 30C or so, join parts etc and pull from the molds. Then, with a very slow ramp-up (5C/hour) you can postcure to 100-120C and you have a plane that can be painted any color and won't need rework for spar bumps and other annoying issues.