This is a partial list of the British
Air Ministry
The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of State ...
(AM) specifications for
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
. A specification stemmed from an
Operational Requirement, abbreviated "OR", describing what the aircraft would be used for. This in turn led to the specification itself, e.g. a two-engined fighter with four machine guns. So for example, OR.40 for a heavy bomber led to Specification B.12/36. Aircraft manufacturers would be invited to present design proposals to the ministry, following which prototypes of one or more of the proposals might be ordered for evaluation. On very rare occasions, a manufacturer would design and build an aircraft using their own money as a "private venture" (PV). This would then be offered to the ministry for evaluation. If the aircraft generated interest in the ministry or RAF due to performance or some other combination of features then the ministry might well issue a specification based on the private venture aircraft.
The system of producing aircraft to a specification ran from 1920 to 1949 during which the Air Ministry was replaced by first the
Ministry of Aircraft Production (MAP) in 1940 and then the
Ministry of Supply (MoS) in 1946. The system was applied to commercial aircraft as well, two being the
de Havilland Comet and
Vickers Viscount. During the period, over 800 specifications were issued.
Specification designations
Each specification name usually followed a pattern. A leading letter was usually present to identify the aircraft purpose. The codes used included B for "heavy
bomber
A bomber is a military combat aircraft designed to attack ground and naval targets by dropping air-to-ground weaponry (such as bombs), launching aerial torpedo, torpedoes, or deploying air-launched cruise missiles. The first use of bombs dropped ...
", e.g., B.12/36, P for "medium bomber", e.g., P.13/36, F for "