Douglas designed the Skylancer as an all-weather version of the F4D Skyray with which it shared the basic configuration. The Skylancer was very stable at supersonic speeds and highly maneuverable. Yet it was not ordered by the U.S.Navy in favour of the F8J Crusader. All four Skylancers built were obtained by NASA to be used as test aircraft, taking part in programs such as the Dynasoar Space-plane test, the lifting body program and research for the supersonic transport program.
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