We’ve written several times about structural batteries in this blog, from Dr. Emile Greenhalgh’s early research at Imperial College to more recent efforts along the same line. Interestingly, the basic idea remains very much the same over a decade. Energy storage would take place in a monocoque-type structure that could use carbon fiber, fiberglass, and even graphene as a structural material, while acting as a battery. Now some of this thinking is being applied to hydrogen storage in wings. “TubeStruct™” APUS, an aircraft design, structure and certification operation in Strausberg, Germany, offering a full range of services including flight training. They recently announced two new craft, both featuring hydrogen fuel systems contained in a novel “… patented structurally integrated hydrogen storage system, known as TubeStruct™.” In the shadow drawings of the airplanes, the tubes appear as though they could double as redundant wing spars. The i-2, a four-seat Normal-Category (CS-23) aircraft; and “The APUS i-6 is a technology demonstration platform …