and Griffith would later go on to work for Rolls-Royce Limited. In 1918 the Royal Aircraft Factory was once more renamed, becoming the Royal Aircraft Establishment (RAE) to avoid confusion with the Royal Air Force, which was formed on 1 April 1918, and because it had relinquished its manufacturing role to concentrate on research. During WWII the Marine Aircraft Experimental Establishment, then based at Helensburgh in Scotland, was under the control of the RAE. In 1946 work began to convert RAF Thurleigh into RAE Bedford. Engineers at the Royal Aircraft Establishment invented high strength carbon fibre in 1963. In 1961, the world's first grooved runway for reduced aquaplaning was constructed. In 1965, a US delegation visited to view the new surfacing practice and initiated a study by the FAA and NASA. On 1 May 1988 the RAE was renamed the Royal Aerospace Establishment. On 1 April 1991 the RAE was merged into the Defence Research Agency (DRA), the MOD's new research organisation. Then, on 1 April 1995 the DRA and other MOD organisations merged to form the Defence Evaluation and Research Agency (DERA). The Bedford site was largely shut down in 1994. In 2001 DERA was part-privatised by the MOD, resulting in two separate organisations, the state-owned Defence Science and Technology Laboratory (DSTL), and the privatised company QinetiQ. Royal Aircraft Factory Aircraft Factory designs Between 1911 and 1918 the Royal Aircraft Factory produced a number of aircraft designs. Most of these were essentially research aircraft, but a few actually went into mass production, especially during the war period. Some orders were met by the factory itself, but the bulk of production was by private British companies, some of which had not previously built aircraft. Up to about 1913 the designation letters referred to the general layout of the aircraft, derived from a French manufacturer or designer famous for that type: S.E. = Santos Experimental (Canard or tail-first layout) B.E. = Blériot Experimental (Tractor or propeller-first layout) F.E. = Farman Experimental (Pusher or propeller behind the pilot layout) From 1913/4 onwards this was changed to a designation based on the role for which the aircraft was designed: A.E. = Armed or Armoured Experimental C.E. = Coastal Experimental (e.g. Royal Aircraft Factory C.E.1 – prototype only) F.E. = Fighting experimental (although they remained "Farmans" in the sense of being pushers) N.E. = Night Experimental (e.g. Royal Aircraft Factory N.E.1 – prototype only)