Ikarus IK-2

[Milos Sijacki]

The Ikarus IK-2 was a high-wing, all metal, single seat, monoplane fighter aircraft of indigenous design built for the Yugoslav Air Force. The IK-2 was designed by Kosta Sivčev and Ljubomir Ilić.

The prototype, designated the IK-L1, of the design was ordered from Ikarus A.D. in 1934, and was delivered for test in 1935. The aircraft was powered by a Hispano-Suiza 12Ycrs inline engine. The armament consisted of a 20 mm HS-404 cannon and two 7.92 mm Darne machine guns, both engine-mounted. The design was similar to the Polish PZL P.8, sharing its Pulawski wing (gull-wing) design, giving pilot an excellent view.

Captain Leonid Bajdak, a biplane advocate, tested the IK-1 in flight. During a full range of tests on the third flight the aircraft failed to pull out of a power dive and crashed. Bakdak bailed out and survived but claimed the IK-1 was not suitable as a fighter. Investigation of the wreckage disclosed that the failure was due to negligence in sewing a seam on one of the fabric covered wings, and therefore a decision was made to proceed with the second prototype, designated IK-2. The second prototype had metal skinned wings and was ready for test in June 1936. A new test pilot, Dobnikar, performed the preliminary flight tests, including a mock battle against a Hawker Fury, a biplane, flown by Captain Bajdak. The IK-2 outperformed the biplane in all respects.

Based upon these tests the Yugoslav Air Force ordered twelve IK-2 fighters, which were all delivered in 1937. In April 1941 when German forces invaded Yugoslavia, the only unit of Royal Yugoslav Air Force armed with this type of aircraft was 4th fighter regiment made out of 33rd and 34th air force groups stationed at Bosanski Aleksandrovac. 4th fighter regiment was armed with 18 Hawker Hurricanes and 8 Ikarus IK-2 fighter planes. On April the 7th, 5 IK-2 with 5 Hawker Hurricanes engaged German fighter planes in a dogfight during German attack on airport Rovine, base of Yugoslav 8th bomber regiment situated north of Banja Luka. During this brief encounter Yugoslav fighters managed to repel attack by 27 German fighters but suffer heavy losses. For the rest of the war IK-2 were used for strafing advancing German columns. At the end of the war all of the surviving IK-2 were handled to the air force of newly formed Independent State of Croatia.

A proposed development of the IK-2 was the IK-4, a two seat reconnaissance monoplane, but it was never ordered.

Variants:

* IK-1L : First prototype.
* IK-02 : Second prototype
* IK-2 : Single-seat fighter aircraft.
* IK-4 : Proposed two-seat reconnaissance aircraft. Not built.

 

[imalko]

Nice post with basic information about first fighter aircraft of indigenous Yugoslav design. Modern at the time of its appearance but hopelessly outdated by the time of the April war in 1941.

 

[imalko]

Here's my contribution to the startup of this new forum section. The years between the wars - the golden age of aviation - were also the golden years of formation and development of Yugoslav aircraft industry. The period was marked by many indigenous designs which were built either as prototypes only or in limited series as well as licensed production of some of the most advanced aircraft of that time, such as Breguet 19, Hawker Furry, Hawker Hurricane, Bristol Blenheim and Dornier Do 17. The inception of commercial air traffic in Yugoslavia can be traced to this period with our first airline Aeroput. Though I believe this aircraft was mentioned on the forum before, I'm starting this new thread dedicated to Yugoslav first indigenous fighter aircraft Ikarus IK-2, which paved the way for development of modern low wing fighter Rogožarski IK-3.

IKARUS IK-2
The Ikarus IK-2 was an indigenous Yugoslav design started as a private venture in 1932 by Ljubomir Ilić and Kosta Sivčev, young engineers educated in France. Only in February 1934 the Ministerial Council gave clearance for building a prototype and job was entrusted to Ikarus AD factory at Novi Sad. The prototype, designated IK-1 (the abbreviation "IK" being derived from Ljuboir Ilić's surname and Kosta Sivčev's first name), first flew on 22nd April 1935. The aircraft was a high wing monoplane with characteristic "gull" wing favored at that time by French and Polish constructors and with metal structure partially covered with canvas. It was driven by Hispano Suiza 12Ycrs 860hp engine and armed with two machine guns in the fuselage and one cannon firing through propeller shaft.
This first prototype was soon lost to an accident, but it was replaced by the second prototype, now under designation IK-2, which flew for the first time on 24th August 1936. Series of trials were conducted against a Hawker Fury biplane, which was then in service with Army Air Force of Kingdom of Yugoslavia (VVKJ - Vazduhoplovstvo Vojske Kraljevine Jugoslavije), revealing that the IK-2 was superior on all counts. Thus a go-ahead was given for series production and by early 1939 first batch of 12 examples was produced and delivered. Though already obsolete on the eve of World War Two, these were pressed into service with VVKJ, first with 6th Fighter Regiment in Zemun and since October 1939 with the 34th Fighter Group, 107th Fighter Squadron, 4th Fighter Regiment in Zagreb. During the short April war in 1941, eight IK-2 fighters were still in service. First taste of combat IK-2 pilots experienced on 9th April when German Messerschmitt Bf109Es attacked Rovine Air Base near Bosanski Aleksandrovac. During the ensuing aerial engagement one IK-2 and two Hawker Hurricane Mk Is were lost, but two Messerschmitts were also shot down. In fallowing days IK-2s were operated mainly in the ground-attack role. Some remaining serviceable IK-2 were burned by their crews to prevent them falling into enemy hands, but Germans never the less managed to capture three IK-2s. These were then pressed into service with newly formed Zrakoplovstvo NDH (Air Force of so called Independent State of Croatia) and finally withdrawn from service in 1944.

TECHNICAL DETAILS
Manufacturer: Ikarus AD
Class: fighter
Armament: 20mm Hispano-Suiza HS-404 fixed forward-firing cannon with 60 rounds in a moteur-cannon installation, two 7.9 mm (0.312 in) Darne fixed forward-firing machine guns in the upper sides of the forward fuselage with synchronization equipment to fire through the propeller disc
Crew: Pilot in an enclosed cockpit
Engine: One Hispano-Suiza 12Ycrs Vee piston engine rated at 860hp (641 kW) at 4000 meters (13,125 ft)
Speed: Maximum: 435 km/h (279 mph; 234 kt) at 4000 meters (13,125 ft), 360 km/h (224 mph; 194.5 kt) at sea level, Cursing: 250 km/h (155 mph; 135 kt) at optimum altitude
Range: 700 km (435 miles; 378 nm); endurance 3 hours 15 minutes
Ceiling:10500 meters (34,450 ft)
Climb: 5000 meters (16,405 ft) in 5 minutes 24 seconds
Length: 7.88 meters (25 ft 10.25 in)
Height: 3.84 meters (12 ft 7.125 in)
Wing Span: 11.40 meters (37 ft 0.875 in), aspect ratio 7.22, area 18.00 m2 (193.76 sq ft)
Weight: empty: 1502kg (3,311 lb), normal take-off: 1857kg (4,094 lb), maximum take-off: 1930kg (4,255 lb)

First picture shows constructors Ljubomir Ilić and Kosta Sivčev in front of the first prototype IK-1 at Belgrade airport in April 1935. Second prototype was presented to the public at Belgrade International Aero Exibition in 1938. (Source of pictures unknown.)

 

[imalko]

During their peacetime service IK-2s of VVKJ were painted in gray color overall with large national insignia on the wings, national flag on the rudder and black tactical numbers on the fuselage. In 1940 camouflage color scheme was introduced together with far less visible wartime national insignia. (Source of pictures unknown.)

 

[RabidAlien]

Nice looking bird, but it appears to have limited visibility...not a good thing for a warplane! Nice pics, though!

 

[imalko]

Agreed. The problem of poor visibility is something which any aircraft with this kind of high wing configuration would have to face. As you said, not a good thing for a fighter! Probably the main reason why the concept quickly became obsolete and not many such designs were built around the world. Actually, the Polish PZL P.11 is the only one which I could think of right now.

 

[HealzDevo]

I also thought it was also the fact that you sacrificed your ability to position yourself and throw yourself around due to the increased stresses of the top wing. Good as an additional wing for potentially long ferry flights to carry fuel, bad for actual combat. Thought they did a biplane modification to spitfires and hurricanes for long distance ferry flights. I know I saw a picture of it once...