R.E. = Reconnaissance experimental (two-seat machines) S.E. = Scout experimental fast single-seat aircraft. The B.S.1 of 1913 was a one-off anomaly, combining both systems: Blériot (tractor) Scout (fighter). R.T. & T.E. were also used for strictly one-off prototypes. Designs produced Several aircraft were produced during the days as the Army Balloon Factory. These include the airships as well as the Cody and Dunne designs. Subsequent Royal Aircraft Factory type designations are inconsistent and confusing. For instance the "F.E.2" designation refers to three quite distinct types, with only the same broad layout in common, the F.E.2 (1911), the F.E.2 (1913), and finally the famous wartime two-seat fighter and general-purpose design, the F.E.2 (1914). This last aircraft was the one that went into production and had three main variants, the F.E.2a, F.E.2b, and the F.E.2d. As if this wasn't enough, there is the F.E.2c; this was a generic description rather than a subtype proper, and refers to several one-off conversions of F.E.2b's that experimentally reversed the seating positions of the pilot and the observer. The B.E.1 was basically the prototype for the early B.E.2 but the B.E.2c was almost a completely new aeroplane, with very little common with the earlier B.E.2 types apart from engine and fuselage. On the other hand, the B.E.3 to the B.E.7 were all effectively working prototypes for the B.E.8 and were all very similar in design, with progressive minor modifications of the kind that many aircraft undergo during a production run. The B.E.8a was at least as different from the B.E.8 as the B.E.7 was. The S.E.4a had nothing in common at all with the S.E.4, while the S.E.5a was simply a late production S.E.5 with a more powerful engine. Several early RAF designs were officially "reconstructions" of existing aircraft because the Factory did not initially have official authority to build aircraft to their own design. In most cases, the type in question used no parts whatever from the wreck, in some cases, not even the engine. British Army Dirigible No 1 Nulli Secundus—1907 Nulli Secundus II—1908 British Army airship Beta – 1910 Dunne D.1 – 1907 British Army Aeroplane No 1 (Cody) – 1908 Dunne D.3 Dunne D.4 Royal Aircraft Factory S.E.1—1911 Royal Aircraft Factory F.E.1—1911 Royal Aircraft Factory B.E.1—1911 Royal Aircraft Factory B.E.2—1912 Royal Aircraft Factory B.E.3—1912 Royal Aircraft Factory B.E.4—1912 Royal Aircraft Factory F.E.3—1913 Royal Aircraft Factory B.E.7—1913 Royal Aircraft Factory S.E.2—1913 Royal Aircraft