My Avro Vulcan prop slot and Arrowhead custom tailed delta. These are in prototyping stages, so there's some exposed wiring and slop, but they are very good birds as far as flying. The original green Arrowhead I posted had tip stall and roll issues from a short-coupled tail plane that probably had air flow issues like a compound shape. The new one has all that worked out and flies like a boss with loops and rolls and the sharpest turns you can imagine.