In 1928 pioneer pilot/constructor A. V. Roe (later Sir) acquired an interest in S. E. Saunders Ltd and firm was reconstituted as Saunders-Roe. First new product was Cutty Sark flying-boat, with Fokker-type wing, built in small numbers; also larger Cloud (1931) of which RAF had 16.
Most successful product was twin-engined London biplane flying-boat of 1934 which served with RAF until 1941. Shrimp two-seat four-engined aircraft was built to serve as research vehicle for larger types. Company built the Supermarine Walrus and Sea Otter in quantity. SR/A1 of 1947 was world's first jet-propelled flying-boat fighter, but was not ordered into service. Princess ten-turboprop commercial flying-boat of 1952 was a great technical achievment, but never entered service. SR.53, first flown in 1957, was experimental turbojet/rocket interceptor which demonstrated climb of about 15,240m/min.
Cierva joined Saunders-Roe in 1957.
Promising SR.177 development was abandoned despite international interest. Company entered helicopter field in early 1950s with small Skeeter (originally Cierva), though in 1928 S.E. Saunders had made Isaaco Helicogyre (which never flew) for the Air Ministry. Five-seat P.531 built 1958, but in 1959 company was acquired by Westland Aircraft, which developed the P.531 as the Wasp/Scout.