My big question that nobody has yet answered is whether the 3D printed metal parts could ever be airworthy. Most aircratf metal is VERY selective. When we restore, we mostly use 2024-T3 Aluminum for skin. We can also use 2024-O soft Aluminum, form it, and then heat treat it to make it into -T3 hardness. Some parts are 7075 and some are other alloys. The strength requirments demand aviation-grade alloys.
If they plane to just display these aircraft, there is no problem.
If they plan to FLY these 3D printed parts, I predict some dire consequences unless they 3D print in wax and use a lost-wax method to cast a part in a proper alloy and heat treat it to the proper hardness for aviation strength and corrosion resistance.
So far, we have restored an old Bell YP-59A Airacomet with proper aviation-grade Aluminum alloys, and properly heat-treated parts that were made with O-Aluminum. Personally, I'd not fly a plane that had 3D printed parts in structural places. Canopies endure a LOT of stress in flight. The stress is all outward and the airflow is trying to suck the canopy off the aircraft. When we needed to construct a canopy frame, the tubing was steel and we welded on some steel gussets that we could attach the Plexi to with bolts. We needed a canopy bow and we made one out a 3 pieces. The top cap was machined by our small group (3 of us) out of a solid piece of 7075 and we carefully removed material until it was the correct shape. 7075 is already hardened, so no further strengthening was needed.
The canopy jettison mechanism was robbed from a Grumman Tigercat, courtesy of Steve Hinton. It was a small bit too thick and I machined off about 0.23" in overall thickness to make it fit. Everything else was fabricated from 2024-T3 or -T6 Aluminum. We didn't do a Finite Element Analysis on the Emergency Canopy Release, but the Airacoment is also not going to see speeds as high as even a standard Tigercat can make. Our piece started off pretty stout and we only removed 230 mills of thickness from a piece that was over 4 inches thick, and everyone who has experience at stress analysis says we will never see a problem.
Wonder if we could say the same had we 3D printed a scintered-metal part? To date, I don't know anyone who can tell me and the testing of the part would be VERY expensive to certify it for flight. Making a 3D model to be scanned and read into a CNC machine program is one thing. Flying a 3D printed part is quite another. My guess is that if they plan to fly it, they print a bit oversize, sand it smooth, and scan it into a machining code program for rendering on a CNC machining center from Aviation grade alloys.