Schreder HP-15 (Paperback)

High Quality Content by WIKIPEDIA articles! The HP-15 sailplane prototype was designed by Richard Schreder as a personal mount in which to challenge the 1969 U.S. National Soaring Championships. With an extreme 33:1 aspect ratio and a relatively low empty weight, the HP-15 was expected to generate less induced drag and therefore higher performance. The type achieved excellent glide ratios in fast flight, but had disappointing climbing ability. This was due to extensive flow separation on the upper wing surfaces during slow flight. After the Championships Schreder re-winged the fuselage to produce his next design, the HP-16.