Scaled Composites's "Prometheus"
Scaled Composite' s Prometheus, built by Burt Rutan in the 90's for high altitude carriage still owns 3 world records, including 63,000 ft. The anhedral in the outer wings is there simply to allow dihedrah in the inner sections to improve gravity fuel transfer.
136157AirshowApr16NAS FWOSHOshkosh17Planes