Computational Analysis of Towed Solar Platform Aircraft

The use of single-sheet planform areas on aircraft can enable both lighter weight construction by eliminating internal wing structures and increased solar power collection through use of bifacial photovoltaic sheets (“bifacial sheets”); the result is > 4X Watts of collected solar energy per kilogram of structure. For single-sheet construction, structural constraints teach toward low aspect ratio designs that do not rely on lift forces being transferred crosswise across wingspans, enabled by towed platform technology. The challenge is developing good aerodynamic lift at aspect ratios of 1.0 and lower. Simulation of digital prototypes identified that the distributed propulsion technologies of Lift Span Tech and cross-over propulsor are particularly effective in single-sheet planform designs. Towed platform technology enables flexible designs that are robust. The combination of robustness and good performance enable 24/7 flight and day missions from the same design. When combined with distributed propulsion, bifacial sheets can displace battery weight, increase lift, prevent boundary layer separation, enable lower-aspect-ratio aircraft at high L/D efficiency, and enable takeoff and landing over shorter and more-diverse surfaces.