 German research during the Second World War had shown the onset of wave drag was greatly reduced by using airfoils that varied in curvature as gradually as possible . This suggested the use of thinner airfoils with much longer chord than designers would have used on subsonic aircraft . These designs were impractical because they left little internal room in the wing for armament or fuel . However , they also discovered it was possible to " trick " the airflow into the same behaviour if a conventional thicker airfoil was used , swept rearward at a sharp angle , creating a swept @-@ wing . This provided many of the advantages of a thinner airfoil while also retaining the internal space needed for strength and fuel storage . Another advantage was that the wings were clear of the supersonic shock wave generated by the nose of the aircraft . 
