Gallery: Let the X-Planes Begin

From Autopia:

Few aircraft are as storied as the experimental series known as the X-Planes. These flying laboratories date to the mid-1940s and took us ever higher, further and faster.

The first, the Bell X-1, was developed to explore transonic flight after fighter pilots began experiencing control problems as they approached the speed of sound in dives. Since then, a long list of X-Planes — and other test aircraft lacking the official ‘X’ moniker — have explored the unknown edge of aerodynamics and aviation. From the early days of supersonic flight and speed records to the possibilities of unmanned combat aircraft, X-Planes have, as their pilots say, pushed the edge of the envelope.

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