There are 2 Derringers. One is Derringer 60 (Aeromodeller September 1993) by Henk de Jong, a top Dutch control line stunt flyer. The other is Derringer 46 by Bob Whiteley, the 1978 U.S. Nats open winner. Anyone can shed any light on these 2 designs like the differences in their flying characteristics, their strong and not so strong points, which design is optimized for what kind of flying style, flying conditions etc etc