The German Air Ministry (Reichsluftfahrtministerium; RLM) had a system for aircraft designation which was an attempt by the aviation authorities of the Third Reich to standardize and produce an identifier for each aircraft design's airframe type produced in Germany. It was in use from 1933 to 1945 though many pre-1933 aircraft were included and the system had changes over those years. As well as aircraft of the Luftwaffe, it covered civilian airliners and sport planes, due to the RLM handing all aviation-related matters in the Third Reich, both civilian and military in nature.
The system
When the Reichsluftfahrtministerium was given control of the country's aviation activities in 1933, it set out to catalog both the aircraft already in production by various German manufacturers as well as new projects approved for development by the ministry. The RLM made necessary improvements to a designation system which had been set up in 1929/30 by the Heereswaffenamt (Army Weapons Office) in the Reichswehrministerium (Defense Ministry), together with other institutions related to the industry. The former system had caused confusion in the use of aircraft designations among the different manufacturers; six aircraft of different firms used the number 33.
The improved designation system was introduced in order to provide a simple and unambiguous identification of every German civilian and military aircraft, be it fixed-wing or rotary-winged, and its corresponding airframe design. The heart of the new system was a (theoretically) unique number assigned by the RLM. In internal paperwork, this number was simply prefixed "8-" (or, in the case of sailplanes, subject to a separate numerical list, "108-"), while "9-" indicated aircraft engines, with 109 prefixing reaction engines (gas turbines, pulse-jets and rockets). The new standardized type designation added two letters representing the manufacturer; Dornier (Do) and Rohrbach (Ro) already used this practice. The first of these two letters was shown in upper case, the second always in lower case, no matter its origin – so Fw for Focke-Wulf or Bf for Bayerische Flugzeugwerke. The very first exemption from this rule was granted several years later to the Blohm & Voss shipbuilding firm, when they renamed their aircraft manufacturing operation – which had been split off from Hamburger Flugzeugbau (Ha) – to Blohm & Voss and received the designation BV for their new aircraft, the first of which was the BV 138 Fliegender Holzschuh maritime patrol trimotor flying boat.
As such the RLM referred to a Messerschmitt twin-jet fighter project internally as type "8-262", although the same aircraft in service would be more generally known as the "Me 262". Originally, these numbers were assigned sequentially and wherever possible attempted to take into account the manufacturers' own in-house design numbers for types already existing in 1933. Duplication resulted from the fact that when one manufacturer abandoned a project, the same number was occasionally re-allocated, with an appropriate time delay, to another manufacturer. One known case that differed from the usual situation involved the airframe number "8-163", used initially for the Messerschmitt Bf 163 competing liaison design that lost its chance at a contract to the Fieseler Fi 156 - the post-July 1938 era's name change from BFW to Messerschmitt AG for the same manufacturer also changed the prefix, the later example being the much more famous Komet rocket-powered interceptor, where the same firm (under a new name and appropriate prefix) re-used the same airframe number.
A parallel designation system was created for piston aircraft engines, using the prefix "9-", with the special 109- prefix replacing it for reaction propulsion (jet or rocket) powerplants.
Prototypes and variants
After February 1935, each individual prototype aircraft were suffixed with "V" (for Versuchs German: "prototype") and a unique identification number for an individual airframe for that design type. So, for example, the Me 262 V3 was the third prototype of the Me 262 built. Later in World War II, with such aircraft as the Heinkel He 162, other letters such as "M" for Muster (model) replaced the "V" designation, and even the Me 262's own later prototypes began using the letter "S" for such models.
Once accepted by Deutsche Lufthansa or the Luftwaffe, major variants of the aircraft were suffixed alphabetically with a capital letter. For example, the major variants of the Me 262 were numbered Me 262 A, Me 262 B, and Me 262 C, often using the German "spelling alphabet" for each major variant's letter.