Ebook: X-15: the world's fastest rocket plane and the pilots who ushered in the space age

Why the X-15? -- The advent of the research airplane -- The X-15 airplane and its engines -- The test arena -- The pilots -- The flights.;"The X-15, which flew from 1959-1970, is still the most advanced research aircraft ever developed and flown, and hangs in a place of honor in the Smithsonian's Air and Space Museum. Its test pilots not only reached the edge of space, but their skill and daring helped engineers understand hypersonic speed and thus pave the way for the Space Shuttle"--