High Quality Content by WIKIPEDIA articles! The Saunders-Roe SR.177 was a 1950s project to develop a combined jet- and rocket-powered interceptor aircraft for the Royal Air Force and Royal Navy. The German Navy also expressed interest in the project, which was cancelled due to changes in Britain`s military policies in 1957. A much larger development was studied under the SR.187 project for Operational Requirement F.155, but this work was also cancelled in 1957, after approximately 90% of the first prototype had been completed.