<hi style=afpcap>One of the few British designs which was adopted by the US Air Force was the English Electric Canberra which was licensed built by The Glenn L. Martin Company as the B-57. Most were of similar appearance to the RAF version, although one was developed with an enlarged wing as the RB-57D, while a second was a Martin/General Dynamics production which bore little resemblance to the Canberra. This was the RB-57F which had an even larger wing, and was powered by Pratt and Whitney TF33 turbofan engines as well as two J60 turbojets to add boost. Twenty One RB-57Fs were converted beginning in 1963 using B-57B, RB-57A and RB-57D airframes which were completely rebuilt and were allocated new serial batches. These served in Europe and the Pacific, as well as with the Weather Service in the USA. Eventually they were redesignated as WB-57Fs to mask their reconnaissance role, with full Military Airlift Command insignia and tail stripe. Three joined NASA for high altitude research work, with one still operational at Ellington AFB, Texas.</hi>
