(Observation) used for a naval reconnaissance aircraft, e.g., O.8/38 – the letter S (Spotter) used for the more specialised role of naval spotting, i.e., observing and reporting back the fall of naval gunfire, e.g., S.38/34 – and R (Reconnaissance) for a reconnaissance type – often a flying boat, e.g., R.3/33. Special purpose aircraft would be signified by a letter Q, this being used to specify aircraft such as target-tugs, radio-controlled target drones, etc., e.g., Q.32/55. Sometimes the purpose for which an aircraft is used in service would change from that for which the specification to which it was designed was issued, and so there are some discrepancies and inconsistencies in designation, the Royal Navy in particular liking to specify multiple roles for its aircraft in an attempt to make the best use of the necessarily limited hangar space onboard its aircraft carriers. In this case this resulted in several types designed to specifications originally intended to signify the naval Spotting role also being used for other purposes, e.g., S.15/33, resulting in the Blackburn Shark and Fairey Swordfish, the latter aircraft being primarily utilised as a torpedo bomber. Similarly S.24/37, which produced the Fairey Barracuda, again primarily designed for spotting, the dive bomber/torpedo bomber requirements being regarded as secondary when the specification was issued, but for which roles it was almost exclusively subsequently used, the original spotting requirement having been made obsolete with the introduction of radar. In addition, some (mostly early) specifications appear to have no letter prefix at all, e.g., 1/21, the Vickers Virginia III. List of specifications (incomplete) The names of the aircraft shown in the table are not necessarily those they carried when provided for evaluation as at this point an aircraft would usually be referred-to as the Manufacturer X.XX/XX, e.g., the Avro B.35/46 – this is in addition to the manufacturer's own separate internal designation for the aircraft, e.g., Avro 698. With several manufacturers submitting designs to the same specification this could result in a number of different aircraft with the same X.XX/XX designation, e.g., Handley Page B.35/46, etc. Upon acceptance of the design(s) the final service names would usually be chosen by the Air Ministry when they placed a production order, in the above B.35/46 cases, where two aircraft were accepted to this specification, Vulcan and Victor respectively. Upon entering service, in the absence of any already-planned variants a new type would initially have no