Behind every world-famous American aircraft – from the cutting-edge Lockheed F-22 Raptor to the long-serving Boeing B-52 Stratofortress – there exists a secret history of aircraft designs that were planned but never built. For every Rockwell B-1 Lancer or General Dynamics F-16 Fighting Falcon that has entered production there have been dozens, perhaps even hundreds, of concepts; evolutionary steps which saw the final design gradually growing and taking shape on the designers’ drawing boards. In the US Aviation Secret Projects series, American aerospace engineer and aircraft development specialist Scott Lowther looks in detail at the vast range of different variants and configurations proposed for some of the United States’ most innovative and advanced aircraft. Each issue is fully illustrated throughout with scale diagrams showing the many different designs studied, with dimensions and technical information provided where known.