Due to the extremely time consuming nature of building the fusealge pod, it's construction was started while other tasks were being done that didn't require the vacuum system. The pod is the heart of the model, holding the engine, wing, cargo, and radio components together. Last year's pod had an inner layer of 5 oz Kevlar, and skin matrix of 1/8" balsa, and an outer shell of 5 oz carbon fibre. It was stronger than hell, 2.5 lbs, and could be used as a deadly weapon if needed. When the model crashed onto its nose during flight trials from a altitude of about 150 ft, the pod was almost completely undamaged (the balsa between the outer and inners layers split, which was easily repaired with a little C/A and accelerator). This year the goal was lightness, without costing too much in strength. The pod construction uses the "lost foam" method, where a foam blank is laminated in material, then dissolved out with acetone to leave the finished shell. Nice and easy, if a little time consuming.
Above Middle: Here you can see the foam being cut to its outline. The blue battery is just acting as a weight. The laminations are held together with a generous bead of 3M77.
Above Right: After the basic pod shape is established, the various bevels are cut with the foam bow. This saves planform area, and makes the finished pod a little more aerodynamic.
Above Middle: Here's another shot of the slicing process.
Above Right: Here you can see the various bulkheads being added. Note that you only need to tack them in place, so a couple of well-placed beads of 5 min epoxy should be fine. You don't need much of a bond to the foam, since it's going to be removed later anyway
Above Middle: Now, carve or hot-wire cut a piece to act as the wing saddle. I used the lower bed off of an endcut from an overly large foam core. Sanding the required incidence angle was a bit of a pain, but worked out in the end.
Above Right: The saddle piece being bonded into place. I'm only using the wing core to avoid denting the saddle with my weights.
Above Middle: Here comes the first round of reinforcements. I like working with Kevlar due to it's shear and abrasion resistance, but the cloth I have is a little heavy (5-6 oz I think). Consequently, I only added a layer around the firewall and nose-gear mount; it's tacked in place with 3M77 . The fibreglass patch and balsa square are to be added to the rear of the pod, with the fibreglass (2 oz) against the foam, and the balsa over top of that.
Above Right: Here are the materials, ready to laminate. I like to wet-out the 'glass cloth layers on the sheet of wax paper that you see taped to the bench, since that allows me to remove as much epoxy as possible.
Above Middle: Here we see the bottom surface being worked on. As in the next few photos, there's a layer of 2 oz 'glass cloth under a layer of 1/16" balsa. The balsa basically just adds thickness to the walls of the finished pod, which makes them a LOT stiffer.
Above Right: And the wing saddle being "balsa-ed". This is thrilling.
Above Middle: Right side being done. This is what, day five of pod making? Yawn.
Above Right: After the pod is completely encased in 'glass and balsa, fill in any inside or strange contours with filler. Carbon and 'glass cloth don't like contouring to them, and neither will the airflow.
