Recently sold on eBay (for $500) was a display model of the Boeing proposal for the C-5 program, which of course lost out to Lockheed. The Boeing design (circa 1965) was vaguely like a Lockheed C-5 merged with a Boeing 747… roughly the configuration and fuselage size of the C-5, but with the raised upper deck and the standard “jetliner” lower tail surface of the 747. I have surprisingly little on the Boeing C-5, but I do have some fairly detailed diagrams of a civilian passenger version, and a few derivatives. Interestingly, while this was clearly part of the genesis of the 747 – which by every metric was a far greater success for Boeing than the C-5 was for Lockheed – it was actually a model 757. As the design effort continued the 747 designation would become the jumbo jet, while the 757 designation would be applied to a much smaller jet.
