ShadowXIX, the Sanger spaceplane was designed in the 20s before they even knew anything about supersonic effects (eg, the joys of compressibility).
The aerodynamics just wouldn't work - NASA learned much from the X-15 (a descendant of rocket technology pilfered from the Nazis). In fact, the
original concept for the X-15 was sketched on a napkin during a lunch break at a conference. But this was some time after they had begun to learn
about supersonic effects.
The Sanger was designed to be able to complete one (1) circuit of the earth, ie a suborbital flight around half the world (dropping a dirty bomb on
New York or other major US city) and then skipping its way to a re-entry back over Europe, where the plane would be ditched and the pilot would eject
for recovery. In other words, the thing was a throwaway space bomber. What we would use these days is an ICBM. No point in putting a human in it and
giving it wings if you can't at least recover it!
Von Braun, however, was keenly interested in making a manned, winged version of the V-2 which would have a big first stage to lob it into suborbit.
That design shares many commonalities with the X-15, aside from the first stage, which was replaced by a B-52. In fact, the spaceplane concept was
supposed to take American pilots (eventually) into space, which it did - some of the X-15 flights topped 100km. It was only the Russians putting an
angry cat down everybody's pants with their huge rocket that force NASA to hastily respond with a Mercury-Redstone launch. As a result, we have a
legacy of ridiculous cost and excess for space programs with governments' insistence on using 1960s technology to launch satellites, manned missions
etc.
But do check out the HyperSoar / FALCON thread.
