The https://www.homebuiltairplanes.com/forums/hangar-flying/16359-goodyear-inflatobird.html thread got me thinking about inflatable structures. In the past, there have been some attempts to make composite kit parts easier to ship such as Steve Rahm's Fold-A-Plane technique for the Vision. Has anyone ever tried inflatable male molds for composite construction?
It seems to me that you could end up with something pretty neat by laying up prepreg (or maybe geodetic strips) over an inflatable mold, which you just deflate and pull out once the composites have cured. Basically, you'd create the external shape (laminate or geodetic) and the spar caps, fuselage longerons, etc. and then, once the mold is removed, bond in the internal spar webs, bulkheads, firewall, end ribs and other reinforcements, all of which would be CNC-cut from flat sheets. Since tapered shapes would be easy to do, the final product wouldn't look quite so amateurish as some.
Inflatable molds made of heavy-duty Zodiac boat-type laminate materials would be long-lasting and reusable--they could be rented to an amateur builder for a fee, returned and rented out to the next builder. By keeping to simple shapes and interchangable (and perhaps all-moving) tail surfaces, you could limit the number of molds, maybe even going so far as a symmetrical airfoil so that left and right wings can be identical (à la Emigh A-2 Trojan). The fuselage could be made on one big plug with the deflated mold pulled out the front, then the firewall bonded in place and the excess trimmed off.
Thoughts? Any pros or cons that I am missing?
Cheers,
Matthew
It seems to me that you could end up with something pretty neat by laying up prepreg (or maybe geodetic strips) over an inflatable mold, which you just deflate and pull out once the composites have cured. Basically, you'd create the external shape (laminate or geodetic) and the spar caps, fuselage longerons, etc. and then, once the mold is removed, bond in the internal spar webs, bulkheads, firewall, end ribs and other reinforcements, all of which would be CNC-cut from flat sheets. Since tapered shapes would be easy to do, the final product wouldn't look quite so amateurish as some.
Inflatable molds made of heavy-duty Zodiac boat-type laminate materials would be long-lasting and reusable--they could be rented to an amateur builder for a fee, returned and rented out to the next builder. By keeping to simple shapes and interchangable (and perhaps all-moving) tail surfaces, you could limit the number of molds, maybe even going so far as a symmetrical airfoil so that left and right wings can be identical (à la Emigh A-2 Trojan). The fuselage could be made on one big plug with the deflated mold pulled out the front, then the firewall bonded in place and the excess trimmed off.
Thoughts? Any pros or cons that I am missing?
Cheers,
Matthew
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