This section describes and illustrates the various national insignia used by the Bulgarian Air Force since its formation:
During the First and Second Balkan wars of 1912-13 many Bulgarian aircraft operated without any markings at all. As encounters with enemy aircraft began to occur it became necessary to identify Bulgarian operated aircraft. To this end, the aircraft rudder began to be painted in the national colours in horizontal bands: white-green-red reading from top to bottom. Farman VII, Sommer and Albatros F.2 aircraft carried these markings. Some sources state that large areas of the wingtips were painted green (port wingtip) and red (starboard wingtip) - if so, this was only on the top wing as photos do not show any underwing markings.
Bulgaria joined the First World War on the side of Germany in October 1915. As virtually all of the aircraft operated came from Germany, the original German national markings were retained. This comprised the 'curved edge' Black Cross on a white square, applied on the fuselage sides, rudder and top surface of upper wings/bottom surface of lower wings. Reports by some sources that a green stripe was added along the trailing edges of the wings is not supported by photographic evidence. Some of the DFW C.Vs and LFG Roland D.IIs were delivered with a version of the marking which reduced the white area to a relatively thin border to the cross.
In mid-1917 some, (but not all), of the DFW C.Vs and LFG Roland D.IIs were delivered with a revised German national insignia, comprising a straight-edged black cross with a thick white border. It was applied in the same locations as the previous markings, often with the white border on the rudder extended to cover the whole rudder. The later LFG Roland D.IIIs and Fokker D.VIIs also carried a version of this marking.
Some sources report that in 1918, a specifically Bulgarian national marking was introduced. This consisted of a black Saltire cross on a white square. The marking was carried on the wings and fuselage sides. It is possible that this marking was introduced to allow identification of Bulgarian aircraft after the surrender (which took place 13 days before the German surrender). It does not appear to have been widely used, with most aircraft retaining German national insignia until scrapped by the Allied Control Commission.
1920s and early 1930s
During the 'twenties and early 'thirties, Bulgarian military aircraft were officially banned. However some clandestine military aviation was conducted by aircraft wearing civilian markings. The civil registration was marked in black on the fuselage and wings, with the national colours displayed in vertical stripes on the rudder. On some aircraft the rudder stripes were white, green and red (front to rear), while others displayed them red, green and white (front to rear). A large black 'B' was sometimes added on the fin to indicate Bulgaria.
With the official establishment of a small air force in 1937, a new national insignia was introduced, in the form of a roundel in the national colours. The rudder marking is not known.
In 1938 an completely new national insignia was officially introduced. This marking was based on the royal coat of arms and consisted of a rampant red lion on a red and yellow Maltese cross with two yellow crossed swords. On a few aircraft a red outline was applied to the fuselage roundel. The rudder marking consisted of horizontal stripes in the national colours - white, green and red from top to bottom.
When Bulgaria joined World War Two on the side of the Axis Powers in 1941, a diagonal black cross on a white square marking was adopted. This marking existed in at least two varieties - with and without a thick black border. In addition, both varieties were displayed with and without horizontal rudder stripes in the national colours.
The threat of invasion by the Soviet Union forced Bulgaria to change sides in 1944. The cross marking was abandoned and replaced by a roundel marking. The roundel comprised a white disc with a red disc in the centre and a green horizontal bar across the middle. On the aircraft wings, the green bar was aligned fore-and-aft in the direction of flight, rather than parallel to the wing as might be expected. Horizontal stripes in the national colours extended across both the fin and rudder, in the order white-green-red from the top.
Adopted at the same time as the above roundel marking, and eventually replacing it, was another roundel design. This roundel was much simpler, in that consisted of the three colours in concentric rings - white, green and red with white outermost and red in the centre. Horizontal stripes in the national colours extended across both the fin and rudder, in the order white-green-red from the top.
After the communist government took over, a new insignia consisting of a red star with the Bulgarian green-red-white roundel in the centre was introduced in 1948. Similar style markings were also introduced at the same time in Hungary and Romania. This markings was displayed in all 6 positions on aircraft (above and below each wing and on the fuselage sides) and was also used as a fin marking. Helicopters carried it on the fuselage sides only.
The main marking is normally displayed in 4 positions (i.e. on the fuselage sides and below each wing) on fixed-wing aircraft - but the MiG-29 and Su-25 don't carry fuselage roundels. The same marking is also used as a fin flash on fixed-wing aircraft. National Markings are NOT carried on wing upper surfaces. Helicopters display the main marking on the fuselage sides and under the fuselage. No service titles are carried.