... give the Ikarus IK-2 the same treatment? That is replace the high wing configuration with a low wing preferably from the IK-3
As promised ...
L for Lovački Avion - The Ikarus IK-L SeriesThe destruction of the prototype Ikarus IK-L1 on 24 April 1935 was a major blow to Yugoslav aviation but opinion on the type had raised strong emotions amongst the fighter pilots of the
Jugoslovensko kraljevsko ratno vazduhoplovstvo (Royal Yugoslav Air Force). Many JKRV planners had pushed for an advanced monoplane type but serving pilots still preferred biplane fighters.
Among those who argued strongly in favour of biplane fighters was JKRV test pilot responsible for testing the IK-L1 prototype -
Kapetan prve klase Leonid Bajdak. While testing the new fighter at Zemun,
kap.VS Bajdak put the high-winged monoplane through a range of violent aerobatic manoeuvres. Having overstressed the prototype airframe, a portion of wing broke off. Bajdak then parachuted to safety as the IK-L1 fell to its doom.
If
kap.VS Bajdak believed that his unauthorised aerobatics had secured him the biplane fighter he had demanded, he would be disappointed. The high-winged monoplane layout of the Ikarus IK-L1 had been chosen as a compromise meant to satisfy service pilots. With the demise of the IK-L1 prototype, it was decided to revert back to the original plan - which had been a fully-modern, low-winged monoplane with a retractable main undercarriage.
Back to 'Plan A' - The Low-Winged MonoplaneThe French-trained designers of the IK-L1 -
inž Ljubomir Ilić and Kosta Sivčev - returned to their drawing boards and revised their high-winged design into the new arrangement. Plans for all-metal construction were dropped (it having become obvious that skilled tradesmen in modern airframe techniques were rare in the Kingdom. Instead, the revised IK-L2 would have plywood-covered wooden wings and a steel-tube fuselage covered in alclad and fabric.
The rear fuselage was essentially identical to that of the lost IK-L1. The forward fuselage was revised to allow for wing mounting and to accommodate cowl guns raised to the uppermost fuselage (although no armament was installed in the prototype IK-L2). [1] First flown on 08 October 1936, the IK-L2 handled fairly well but the tail surfaces lacked authority. It was obvious that the prototype could benefit from a longer rear fuselage and, with that, it lost its remaining structural similarities with the IK-L1.
Top: The prototype Ikarus IK-L2 in its original, short-fuselaged form.
Ikarus Rises - The IK-L2 Into ProductionBy the time that the IK-L2 prototype was returned to the Ikarus assembly shed for its rear fuselage modifications, monoplane fighters - like the Polikarpov I-16, Fiat G.50, and Messerschmitt Bf 109 - were already flying. Accordingly, it was decided to launch into immediate production based on the design of the revised prototype. Other changes introduced were a stiffer tailplane (to eliminate bracing wires); a new, sliding cockpit canopy; and a Hydromatic propeller - the latter necessitating a re-profiling of the nose for the enlarged spinner. [2]
The first '
serija 1' IK-L2
Vetruška (Kestrel) was powered by a French 860 hp Hispano Suiza 12Ycrs engine and armed with 4 x FN Browning machine guns - 12.7 mm cowl guns and a pair of 7.92 mm guns in the wings. A dozen such aircraft were delivered by the end of 1939. The '
serija 2' fighters were identical other than standardising on four 12.7 mm FN guns. The '
serija 3'
Vetruškas were a direct result of the fall of France and Belgium in 1940. Of necessity, substitute engines were sourced from German-occupied Bohemia-Moravia (in the form of 850 hp Avia-built HS 12Ydrs V12s). Armament was reduced to 4 x Czech 7.92 mm
Letecky kulomet vz. 30 guns.
Bottom: A '
serija 3' IK-L2
Vetruška fighter assigned to the JKRV's 161.
Eskadrilla, 51.
Grupa in April 1941.
Prior to the 06 April 1941 invasion of Yugoslavia, IK-L2
Vetruška deliveries had slowed to a crawl due to wartime supply challenges. A planned 6-gunned '
serija 4' stalled when deliveries of Czech-built engines and machine guns ended. Likewise, the proposed IK-L3 powered by a German DB 601A progressed no further than a single IK-L2 '
serija 1' conversion. Had the production Ikarus IK-L3 been realised, it would have been armed with twin synchronised 7.92 mm MG 17 cowl guns with a pair of 20 mm MG FF cannons mounted in the wings.
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[1] Those raised cowl guns displaced the 20 mm autocannon planned for the IK-L1. It had proved difficult to get the French to commit to selling (or licensing) the new HS 404
moteur-canon and the Oerlikon FF alternative was less appealing to JKRV planners.
[2] The change was prompted by potential delays with French Ratier units. Hydromatic props could be sourced from De Havilland or, in the event of a wide-scale European war, from Hamilton-Standard in the US.