Single-Seat, Single-Engine Fighter
Production of the promising Rogozarski IK-3 series was cut short by the German invasion of Yugoslavia during World War 2.
Authored By: Staff Writer | Last Edited:
When covering the range of topics concerning aviation in World War 2, it becomes accepted practice to overlook the developments of lesser-known militaries such as that of the nation of Yugoslavia. During the years stemming from World War 1, the biplane was "king of the skies" until the arrival of the metal monoplane in the years following. Gone were the days of the open-air cockpit, fixed-position spatted landing gear legs and strut-supported high-mounted wings. In its place came the sleek designs that would go on to dominate the air war of World War 2 - chief among these early contributors being the British Hawker Hurricane and Supermarine Spitfire and the German Messerschmitt Bf 109. For the Yugoslavian aviation industry, the global technological changes in aviation did not go unnoticed for development work eventually began on comparable and capable fighting aircraft.
Design on a new "modern" fighter began as early as 1933. Indigenous endeavors had already produced the first all-Yugoslavian fighter in the "IK-1" series prior - a high-wing, fixed undercarriage monoplane fighter - and thought was given to a much improved attempt in the upcoming "IK-3". Finalization occurred in 1936 to which the military took stock in the program. The military review undoubtedly led to costly delays in the modern fighter design attempt for opponents were reluctant to pursue a radical departure from the accepted norms. Regardless, a prototype was ordered in 1937 and an assembly line was rigged at the Rogozarski plant of Belgrade. As such, the aircraft was designated as the "Rogozarski IK-3" though the design was the work of two engineers - Ljubomir Ilic and Kosta Sivcev, they being originators of the earlier IK-1 mark.
Outwardly, the IK-3 was a modern instrument for its time - the fuselage was sleek with clean lines throughout. The engine - an Avia (Hispano-Suiza) 12 Ycrs 12-cylinder engine of of 910 horsepower - was situated at the front of the fuselage and powered a variable pitch three-bladed propeller assembly in a conventional fashion. The cockpit was set amidships behind the engine compartment and the empennage was traditional in its shape, capped by a small rounded vertical tail surface and a pair of mid-mounted horizontal tailplanes. The main wings were low-mounted affairs fitted ahead of center and featured rounded tips. The undercarriage was completely retractable and made up of two single-wheeled main landing gear legs and a tail wheel. The pilot sat under a framed cockpit with decent vision overall though viewing over the long-running engine compartment was detrimental when taxiing on the ground. Of note is that the cockpit was also given a bulletproof windscreen, an accepted practice in most every World War 2 fighter to come. The rear view was blocked by the raised fuselage spine. Armament was a single 20mm Hispano-Suiza HS-404 cannon mounted in the engine block and firing through the propeller hub as well as a pair of 7.92 FN-Browning machine guns fitted in the engine cowling. The armament was entirely situated in the nose of the aircraft which opened up valuable internal volume in the wings for fuel and reduced wing loads. Overall construction was of an internal steel tube structure with wood, covered over in canvas and metal skin. Power from the single engine installation included a top speed of 327 miles per hour with a range out to 310 miles. The aircraft's service ceiling was approximately 26,250 feet.
The first IK-3 prototype was flown in May of 1938 though this developmental form was fitted with a Hispano-Suiza 12 Y29 series engine of 910 horsepower. Performance and handling were all deemed strong points of the design and further testing ensued. An initial production order of 12 aircraft was on the books by then though the project experienced a serious setback in 1939 when a test flight resulted in the loss of the prototype - this killed the pilot at the controls who was unable to bring his plane out of a dive. The unfortunate accident led to a delay in formal production set to begin at Rogozarski until the matter was settled. Once the airframe was cleared of any engineering faults, the production schedule was enacted with six production-quality aircraft being completed. These were delivered to awaiting Yugoslav elements in March of 1940. Follow-up deliveries of this initial order commenced in the months following with a further order of 25 aircraft in the works. Furthermore, Yugoslavia had entered into talks with Turkey for local-license production of the promising aircraft.
By this time on the world stage, Adolf Hitler had consolidated his power across German politics and earned the loyalty of the military - setting about plans to dominate half of Europe within thenext few years. His direction took over the nations of Czechoslovakia, Poland, Belgium, Holland, Netherlands, Norway and France before turning his attention to Yugoslavia - the invasion beginning on April 6th, 1941. A combined force (made up of Germany, Italy and Hungary elements) emerged from neighboring Hungary, Romania, Bulgaria and Italy as Axis forces struck a decisive victory against the unfortunate Yugoslavians.
During the Axis invasion, only six IK-3 fighters were in operational condition and these few models were put to the test. In practice, the aircraft attributed themselves quite well considering the circumstances. The IK-3 was noted for its agility, handling, flight characteristics and appropriate firepower. Reliability and the inherent power of the engine proved sound even when pitted against the might of the German Luftwaffe. As many as 11 enemies are said to have been downed in the fighting, a testament to the Yugoslavian design as well as pilot prowess. Despite the valiant attempts to defend their homeland, the Yugoslavian Air Force proved no match for Axis numbers, experience and tactics. The invasion ended on April 17th, 1941 with the surrender of the Yugoslavian Army - effectively bringing an end to Yugoslavia as a nation itself. Croatia took its place and other territories making up the former country were divided and occupied by the victors until Soviet "liberation" in 1944.
Only two IK-3 fighters managed to survive the invasion by the end of the fighting. However, Yugoslavian personnel saw to their destruction rather than leave the technology in enemy hands. The remaining 25 IK-3 aircraft on order were only half-completed at the time of the fall of Yugoslavia, bringing an end to the short-lived operational service life of the Rogozarski IK-3. Yugoslavian engineers were also considering evermore powerful engines should the Axis invasion never have disrupted development. The post-war Ikarus S-49 was developed from the pre-war IK-3 of which 158 were produced, becoming the first Yugoslavian fighter development of the post-war world.