Mar 132015
A recent ebay auction was for a display model of the early 1970’s McDonnell-Douglas Incremental Growth Vehicle. This was a proposed manned hypersonic “X-Plane,” designed from the ground up to be capable of having major components replaced. This would allow a simple rocket vehicle to be tested first, and then the fuselage could stretch, or new rocket engines tested, or new wings, or new wings, a fuselage stretch and airbreathing engines, whatever the experiment called for.
