The successes of aircraft such as the Hawker Hunter, the B-47, and F-86 showed the value of the swept wing research acquired from Germany. Eventually, almost all advanced design efforts for high speed aircraft would incorporate a wing with a swept leading edge, with either a swept wing or delta wing planform. The Boeing B-52, designed in the 1950s, continues in service as a subsonic long-range heavy bomber.[87][88] While the Soviets never matched the performance of the Boeing B-52 Stratofortress with a jet aircraft, the intercontinental range Tupolev Tu-95 turboprop bomber with its near-jet class top speed of 920 km/h, combining swept wings with propeller propulsion, also remains in service today, being the fastest propeller-powered production aircraft.[89] In Britain, two swept-wing bombers entered service, the Vickers Valiant (1955)[90] and the Handley Page Victor (1958).[91]