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The AstroFlight Sunrise was an unmanned experimental electric aircraft technology demonstrator and the first aircraft to fly on solar power. First conceived in November 1970, the Sunrise first flew on 4 November 1974 from Bicycle Lake, a dry lakebed on the Fort Irwin Military Reservation. The first prototype was destroyed on its 28th flight by turbulence. The improved Sunrise II flew the following year.〔 ==Development== While working as an engineer at Hughes Aircraft, Roland Boucher began design work on an electric-powered aircraft concept in November 1970, calculating that the contemporary nickel-cadmium batteries available would be sufficient to sustain flight using a radio-control model glider. Early experimental projects proved the concept sound and in 1973 Boucher turned his attention to the creation of a high-altitude solar-powered aircraft that would have unlimited endurance.〔 Boucher explained the project to his superiors at Hughes Aircraft in 1972 and after reviewing it, the company released the project to Boucher in 1973. Boucher took a leave of absence from Hughes to pursue the project and joined his brother, Bob Boucher, at AstroFlight, a small model airplane manufacturer in Venice, California. After successfully flying an electric drone carrying a payload on a DARPA project for Northrop Corporation, they then moved onto Project Sunrise. Using commercially available off-the-shelf solar cells producing only 10% efficiency, Boucher calculated that his project would need to be able to fly on about . The aircraft was envisioned as an unmanned sailplane that would have an operating altitude of , powered by a single Samarium–cobalt magnet electric motor, the first motor of its kind in the world. The aircraft would use no batteries and, instead, would descend at night from its operating altitude to about at dawn, before solar energy was once again available for climb. Boucher saw the Sunrise as a proof of concept for a follow on aircraft that would be capable of remaining aloft for months at an altitude of .〔 ''Project Sunrise'' was funded by DARPA commencing in January 1974 and administered by Lockheed Aircraft Corporation of Sunnyvale, California, with the contract specifying a "proof of concept aircraft powered solely by incident sunlight on the wing surfaces."〔 Roland Boucher took on the task of the structural design, aerodynamics, telemetry, control and navigation. He also designed the integration of the solar panel, electric motors, gearbox and the propeller. He selected an Eppler 387 airfoil for the wing. The solar cells were round commercial units provided by Heliotech. The actual airframe was constructed by a team under expert model builder Phil Bernhardt.〔 The Sunrise's wing span was and the aircraft had a gross weight of . The wing loading was a very low 4 ounces per square foot (0.011 kg/sq m). The aircraft structure was built from spruce, balsa and maple. Due to their roughness the solar cells were only mounted on the aft two-thirds of the wing's upper surface.〔 The wing spars were built from spruce spar caps with maple doublers at all attachment points and two balsa shear webs attached to balsa strips on the wing spars. The ribs were made from balsa. This construction resulted in a balsa spar box with tapered spruce caps. The leading edge was covered with balsa to form a leading edge D spar. The trailing edge was formed by two wide sheets forming a triangle with vertical spar sections in between the ribs. The covering was 1/2 mil Mylar. The span wing weighed and was capable of loads up to 100 pounds. Control was via an S & O Radio designed and built telemetry transmitter and receiver. The standard S&O six channel radio had channels for elevator, rudder, motor on and off and solar cell operating mode. The solar cells could be set for either series or parallel operation. The telemetry functions provided gave data on motor current, motor voltage, motor RPM, airspeed and two heading references from a sun compass for navigation.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「AstroFlight Sunrise」の詳細全文を読む スポンサード リンク
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