As used here, an experimentalorresearch and development aircraft, sometimes also called an X-plane, is one which is designed or substantially adapted to investigate novel flight technologies.[1][2][3]
editAvro 707 research aircraft in formation with Avro Vulcan bomber prototypesFairey Delta 2 research aircraftGloster E.28/39 jet engine research aircraftMiles M.35 Libellula canard research aircraft