Ikarus Ik-2 - Royal Story 4yf1q

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Ljubomir Ilić and Kosta Sivčev stand in front Ikarus IK-L1 before the first flight 22. April 1935. Zemun airfield Photo Yugoslav Aviation Museum The basic requirements are engine power, climb, speed, firepower and manoeuvrability .These requirements, with high powered engine (at this time), dictated a metal mainframe construction. Basic aerodynamics design work was completed by early 1933.An Accurate wooden scale model was tested at the Paris -Eiffel wind tunnel, and some aerodynamic improvements were incorporated. Initial proposal for building

the fighter was given by Air Force Command on September 22nd 1933. The prototype was ordered from IKARUS -Zemun factory in 1934. The prototype was planned for completion at the end of 1934. The fighter was designated IK-L1, letters I and K stands for Ilić and Koča( Kosta Sivčev’s nickname), and L1 for “Lovac”Fighter and number 1 indicates the first prototype.

Ikarus IK-L1 during development of the factory Ikarus-Zemun in 1934. Photo Malcolm ingham via Nenad Miklušev

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Ikarus IK-L1, with aerodynamic trim landing gear which have added some 8-10 km / h at a maximum speed of aircraft Ik-L1. Airfield Zemun, April 1935. Photo Malcolm ingham /Vaclav Klepacki via Nenad Miklušev

Ikarus IK-L1, in ments published in the Yearbook of the Yugoslav Aviation in 1936.

Ikarus IK-L1 with aerodynamic trim removed landing gear, April 1935, Zemun airfield Photo Yugoslav Aviation Museum The main plane was completed in September 1934, but some modifications delayed the first test flight until the April of 1935.The test flight was made by Captain Leonid Bajdak, despite the stronger critics of the new concept of IK-L1 fighter. Bajdak did not accept the mandatory flight test programme and

chose his own, which consequently led to the doom of IK-L1 prototype. The first test flight was conducted on April 22nd 1935 at Zemun airfield, with captain Leonid Bajdak at the controls. This first flight was uneventful and IK-L1 proved it’s original conception. The second test flight

The view from the side of the Ikarus IK-L1 before the first flight at the airport Zemun, 22 April 1935. Photo Yugoslav Aviation Museum

was made the following day and Bajdak put the plane into sharp manoeuvres and aerobatics. After the landing the wing fabric cover was loose, but this was explained by not completely dried varnish. More aerobatics were made on the third and final flight of IK-L1, on April 24th. Captain Bajdak again exceeded flight limits and at 1000 metres went into a shallow dive , pulling out too sharply. Loose fabric cover at the starboard wing leading edge tore and was flapping which could be clearly seen from the ground. IK-L1 went into spinn and Bajdak baled out safely. The plane crashed at the Zemun airfield limits. In Bajdaks post accident report, he states that plane is well balanced, with precise response to the controls, but complains of poor visibility from the cockpit. He also referred that the take off run is too long (300m), but this distance is normal for such a high speed aircraft (over 400 km/h). This judgement is given by Bajdak, a pilot habitual with obsolete biplanes only. It was not possible to give any definitive conclusion after just three test flights, and Ikarus factory decided to build a second prototype, to prove the standard of its fabrication and to prove the skill of the designers. The second prototype , the IK-02 was built in just 10 months with the plane being test flight ready on August 24th 1936. The difference between IK-L1 and IK-02 was the metal skin on the wing. In fact, the whole aemaketar plus 3/2013 15

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roplane was of metal construction, apart from the fabric covering of the rear fuselage and tailplane. The new test pilot was Poručnik (Flight Lieutentant) Janko Dobnikar. The new test programme was held at the newly formed Test Group facilities at Zemun airfield. Janko Dobnikar gradually mastered the aircraft , and during the display flights even completed an inverted Immelmann turn and inverted loops. In mid- October 1936, IK-02 obtained a speed record of 435 km/h, the unofficial European speed record for aeroplanes with fixed under carriages. During 1937, the IK-02 was tested in 16 mock dog fights against the Hawker Fury- the Ikarus plane winning in all aspects, outclimbing, out turning and and faster than it’s opponent. Leonid Bajdak was still not convinced in IK-02 supremacy and on one occasion expressed his doubts too loudly. Dobnikar, provoked, could not resist and challenged Bajdak to a duel. The of the contest were: Climb to 4000 m over the Zemun airfield, then race en route Belgrade-Novi Sad-Belgrade (140 km) and dogfight over Zemun airfield. Bajdak in the Hawker Fury and Dobnikar in IK-02 took off together. The IK-02 won this round reaching 4000m first, then heading to Novi Sad, winning the second round too. The final round was held over the Zemun airfield, when skillful pilots attempt to keep their opponent in gunsight. Despite the Bajdak’s attempts to position his Fury , Dobnikar caught his opponent and kept him in his gunsight until the end of dogfight. Bajdak was finally forced to give up and it IK-02 victory. The second prototype IK-02, was later assigned as No.1 and was lost in June 1940. Flying in a thunderstorm the plane was hit by lightning, and caught fire. Captain Milan Bjelanović was forced to parachute out from the burning plane. Bjelanović landed safely, but IK-02 was lost. IK-02 testing proved the aeroplanes strengths and an initial order of 12 IK-2 ,as series production plane was designated, was placed on November 20. 1937. Six IK-2 were delivered in December 1938 with another six on February 1939. By mid 1939, 12 IK-2 became operational and were assigned to Belgrade(Zemun) 6th Lovački Puk (Fighter regiment). In October 1939, the IK-2 unit moved to ZagrebBorongaj 4th Lovački Puk and were concentrated in 34th Grupa, 107th eskadrila. As the threat of war increased, 4th Lovački Puk was despatched to Bosanski Aleksandrovac , near Banja Luka (now Bosnia) airfield, on March 13th 1941. IK-2 War story Peace time acctivities were terminated on April 6th 1941, when the German-Italian invasion started. Only 8 IK-2s were operational, four (2103,2104,2111,2113) were in repair workshops, in Zagreb and Zemun. On the first day of war, 107 Eskadrila patrolled over the Bosnia district , guarding the 8th Bomber Puk , Nova Topola airfield. The second day was uneventful, but on April 8th, pair of IK-2s chased a German recconaissance plane, without success . One IK-2 force landed at Bosanski Aleksandrovac and was written off, leaving seven IK-2s operational. April 9th was foggy and did not promise any flight activities, IK-2s accomplished a patrol over the Nova Topola airfield, when at 14,00 hrs , 27 German ME 109 Es were observed. IK2s were just on landing approach, one plane overshot and attacked the Messerschmitts while another landed for refuelling. In just one minute, a lone IK-2 pilot was attacked by no less than nine Messerschmitts. Sergeant Branko Jovanovic, avoided enemy cannons by pure skill and IK-2 manoeuvrability 16

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Photo of Ikarus IK-02, the second prototype, with the signature of a test pilot, Captain Janko Dobnikar, dated to the middle of October in 1936. Photo Dobnikar collection

Ikarus IK-02, view from the front, center on the complicated structure of the landing gear and wing struts.  Image created during testing in October in 1936. Airfield Zemun. Photo Dobnikar collection

Ikarus IK-2, Br1, the first International aviation exhibition in Belgrade, May to July in 1938. Photo Alex Imrie collection via Nenad Miklušev and managed to land safely. The remaining 4th Puk aircrafts, 8 Hurricanes MK I and five IK-2 were alarmed and took off for combat. The sky over Nova Topola was full of Yugoslav and German aeroplanes, fighting . After the less than 10 minutes, the German fighters broke off and headed toward Austria, leaving two Messerschmitts shot down and a few badly damaged. One IK-2 (flown by Sergeant Stikuc) and two Hurricanes were shot down. Only six IK-2s remained, until April 10th, when one IK-2 force landed due to engine failure. April 11th was the last day of IK-2 activities, when one IK-2 was flown to Veliki Radinci airfield,where it was bur-

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ned on April 13th by its own crew , together with 6th Puk Rogožarski IK-3s, BF 109 E-Emils and other fighters. The war story of IK-2 was not finished yet. German units captured four IK-2 fighters (2103,2104,2111,2113), and one , No 2106 was found damaged but repairable on the war airfield in Bosnia. The planes were overhauled in repair workshops in Sarajevo and Zemun. IK-2s were given to the newly created Croatian Independent State air force. Serial numbered 2901,2902,2903,2904, with the fifth IK-2 serial unknown. These planes served at 2 Zrakoplovna Luka (Air base) Rajlovac near Sarajevo in 6th Grupa 17. Jato ( 6th Group 17th Flight). During late 1942 , they were transferred to 5. Jato(5th flight) in Banja Luka, where they served until 1944. but due to a shortage of spare parts just two were operational. In 1944 all the IK-2 were withdrawn from service and not a single sample survived the war.

Detail of the landing gear on the Ikarus IK-2, Br1, exposed to the first International aviation exhibition in Belgrade, in 1938. Photo - Nenad Miklušev collection

Detail of the nose fuselage and a cannon in the propeller shaft to the Ikarus IK-2, Br1, International aviation exhibition, Belgrade, in 1938. Photo Alex Imrie collection via Nenad Miklušev

Another view of the landing gear detail on Ikarus IK-2, Br1, Darne machine gun position on the side of the hull and a small window on the side, through which the pilot could not estimate the height of flare on landing. Photo Alex Imrie collection via Nenad Miklušev

IKARUS IK-L1 / IK-02 / IK-2 CONSTRUCTION Fuselage: Chrome-Molybden steel tube structure with sheet duraluminium covering at engine and cockpit section, fabric covered aft cockpit section and tailplane. Pilot Plexiglass sliding canopy slid down into fuselage sides, like car side windows. Wings: Gull wing (Pulawski wing) configuration,.The shoulder high wing, all metal structure,with front and rear box spars , prototype(IK-L1) fabric covered, IK-02 and series production IK-2 have metal duraluminium skinning . Semi cantilever type with attachments of wing roots to upper fuselage and wing struts to lower fuselage attachment points. Ailerons were metal frame, fabric covered,located at dummy spars and have twin features, working as ailerons , but could be deployed as landing flaps,to a maximum of 15 deg. Tailplane: All metal frame with fabric covering , aerodynamically and mass balanced ,tailplane trim was adjustable in flight. Landing gear: Fixed main gear and steerable tailwheel. Main undercarriage employing Messier Oleo-Pneumatic shock absorbers and pilot operated wheel brakes.Spats were installed on prototype and first series production plane, but were later removed. Engine: One 860 HP (at 3100m) Hispano Suiza HS 12 YCrs, liquid cooled 12 cylinder-upright Vee inline engine. Supercharger is set at 3100m .Ratier three blade propeller was pitch adjustable type and was driven via reduction gear. Engine cooling system was Chausson type and located under the fuselage. Fuel and oil tanks were placed in the fuselage, in front of the cockpit compartment.IK-L1 and IK-02 were powered by originally French built HS engines, series produced IK-2s (12 planes) were powered by Czech licence built AVIA HS 12 YCrs engines. Armament: IK-L1 crashed before any armament was installed for trials. IK-02 was armed with Oerlikon FF 20 mm cannon and two DARNE M.30 7,7 mm machine guns. IK-2 series production planes were armed with two fuselage side mounted DARNE Mle 1930 7,7 mm machine guns with 250 rounds per gun and one Hispano HS-9 , hub firing 20 mm cannon with 60 rounds. In 1940, some IK-2s were rearmed with one 7,92 mm FN machine gun replacing HS-9 20 mm cannon, but until February 1941, almost all

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Ikarus IK-2 Br.2110, Black 2, 6th Fighter regiment at the airfield Zemun, 1939. Photo Šime Oštrić collection Ikarus IK-2 during the early period of use in the 6th Fighter regiment in Zemun 1939. Photo Dobnikar collection were rearmed to original configuration. Standard RYAF gunsight installed on IK-2 was Kretien gunsight (similar to ALDIS tube gunsight) or simple ring and bead gunsight. Ikarus IK-L1/IK-02/IK-2 colours and markings The state of WW II RYAF colours data in modelling and historical references are more or less chaotic at best. Therefore, colours defined in this publication are useful primarily as guides to further research, since little or no colour correlation in Yugoslav sources can be found. Ikarus IK-2 became operational in 1939. Overall silver scheme was retained as was

used on previous RYAF fighters in early 1930s. The first prototype IK-L1, second prototype IK-02 and a whole series of 12 produced planes was delivered in this simple scheme, with 120 cm dia. RYAF “Kosovo Cross” insignia placed in four positions on the wing, State Flag (Light Blue/White/Red) was painted on the rudder. Small black inscriptions, like IKARUS A.D. logo, type and engine data as well as c/n were painted on the vertical tail. In late 1939 all the remaining IK-2 fighters were repainted in a new, camouflage scheme, consisting of three topside camouflage paints -Dark Green, Dark Brown, Ochre and Light Blue Gray undersurface paint, similar to other RYAF fighters , IK-3 and Hurricane MK I. .

Another view of the Ikarus IK-2 Br.2110, Black 2, during a brief service in the 6th Fighter regiment. Photo Šime Oštrić collection 18

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Captain Žarko Vukajlović, C.O. of the 107th Squadron 34th Fighter groups, 4th Fighter regiment merely ahead of its IK-2 in the summer in 1940. The airfield Borongaj. Photo collection of family Vukajlović

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Ikarus IK-2 No. 2104, charged through the nose, airfield Borongaj near Zagreb, in the winter 1940. Photo Šime Oštrić Royal Yugoslav Air Force Ikarus IK-2 scheme as used by IKARUS factory paint mix receptures. (Note, these Ikarus factory paints are close, but not identical with Rogožarski and Zmaj factory paints , used on IK-3 and Hawker Hurricanes)! Svetlo sivo plava - Light Blue Gray FS 35352 Oker žuta - Ochre Yellow FS 30219 Tamno zelena - Dark Green FS 34108 Tamno smeđa - Dark Brown FS 30108 Croat NDH AF Ikarus IK-2 scheme: Tamno zelena N-17 - Dark Green FS 34096 Siva N-16 - Gray FS 35526* close match Three colour paint pattern on RYAF is sprayed with fine, soft edges between paint patches. All the paints used are matt.

Cockpit colour is left in natural metal aluminium primer, and matt black instrument . All the stencilling was done in black. Some planes, like No 2105/white 29 have natural metal/aluminium painted canopy frames. Ikarus Ik-2 markings Royal Yugoslav Air Force markings -”Oznaka Vazduhoplovstva Vojske Kraljevine Jugoslavije” -VVKJ , Kosovo Cross , was defined by strict rules and was, in late 1930s standardised . Usually,silver painted IK-2 fighters wears 120 cm dia markings. These were placed on the wings only, in four positions, two on topsides, two on undersides. Peacetime overall silver scheme with large markings was changed to camouflaged

scheme Just before WW II, new VVKJ Markings and Camouflage rule was issued and marking size and its number was reduced, retaining one marking on wing topsides and undersides but this was not implemented on all fighters in service. Photo evidence confirms that IK-2 markings stayed intact on undersides and one topside marking was overpainted, while another was reduced to 70 cm dia, usually placed at port wing top surfaces. Some planes had two small markings on wing topsides, and some had 100cm dia markings on undersides. Large black squadron numbers on overall silver IK-2s were overpainted and did not appear on camouflaged planes. Some IK-2s painted in masking scheme, wear white large squadron numbers, photo confirmed are No 29/2105, No 31/2107 and No 34/2110. It is clear that the row of white numbers corresponds to 4.th fighter regiment order of battle and plane inventory, where 24 Hawker Hurricanes belongs to 33rd and 34th Fighter Group and 12 IK-2s were despatched to this (34th) unit in late 1939. Supposedly, operative IK-2s from Zagreb-Borongaj bear white numbers in 25-37 range. A large state flag was painted on overall Silver painted IK-2s, and a small one was painted on the camouflaged IK-2s. Construction numbers- C/N, VeBR serials, factory and service inscriptions were black on silver and camouflaged planes.The-

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IKARUS IK-2 production list Ikarus type

c/n

VeBr./serial

Comment

IK-L1

1.st proto.

-

Crashed April 1935.

IK-02

1

No 2101

Crashed June 1940.

IK-2

c/n 2

No 2102

IK-2

c/n 3

No 2103

Croat N 2902

IK-2

c/n 4

No 2104

Croat N 2901

IK-2

c/n 5

No 2105

IK-2

c/n 6

No 2106

IK-2

c/n 7

No 2107

IK-2

c/n 8

No 2108

IK-2

c/n 9

No 2109

IK-2

c/n 10

No 2110

IK-2

c/n 11

No 2111

IK-2

c/n 12

No 2112

IK-2

c/n 13

No 2113

Damaged 10.10.40.repaired

white 29 Unknown Croat No

Captured by Croat units

white 31

Black 2 , later white 34 Croat N 2903 Croat N 2904

Ikarus IK-2/IK-02/IK-L1TECH CHART IKARUS IK-L1

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IKARUS IK-02

IKARUS IK-2 (series )

Engine

HS 12 YCrs 860 HP

HS 12 YCrs 860 HP

AVIA HS12YCrs 860HP

Wingspan

11,40 m

11,40 m

11,40 m

Lenght

7,88 m

7,88 m

7,88 m

Height

3,84 m

3,84 m

3,84 m

Wing area

18,00 m2

18,00 m2

18,00 m2

Empty weight

1440 kg

1502 kg

1502 kg

Take off weight

1650 kg

1875 kg

1875 kg

Fuel

150-200 Lit (reduced)

240 kg

240 kg

Oil

20 kg

20 kg

20 kg

Max speed (0m)

360 km/h

360 km/h

360 km/h

Max speed (3000m)

435 km/h

435 km/h

435 km/h

Cruise speed

250 km/h

250 km/h

250 km/h

Landing speed

130 km/h

130 km/h

130 km/h

Take off run

130 m

130 m

130 m

Landing run

300 m

300 m

300 m

Climb to 5000m

5 ‘ 25”

5 ‘ 25”

5 ‘ 25”

Endurance ( cruise )

2 hr 20 min.

2 hr 20 min.

Cruising altitude

4000 m

4000 m

Ceiling

12000 m

12000 m

Range

700 km

700 km

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Ikarus IK-2, No.2105-White 29, on exhibit in the “French Pavilion” of the Zagreb Intarnational Fair in 1940. Photo ex-AirSerbia Forum se data were painted on both rudder and fuselage sides. There was a mix of inscription styles, some planes were inscripted in cirylic letters, some in latin. Ikarus IK-L1 was c/n 01 and have cirylic written IK-L1 Br-01 on rudder, while Ikarus IK02 bears mixed inscription, IK in cirylic and N02 in latin letters.

Another photo of the same aircraft, Ikarus IK-2, No.2105-White 29, the same exhibition, Zagreb, 1940. Photo ex-AirSerbia Forum

Series produced IK-2, in silver scheme bear IK-2 Br 01 and later were serialed in IK-2 Br 2101 - Br 2113. These numbers were repeated on camouflaged planes, now written in latin letters, No2101 - No2113. Hispano Suiza- HS-YCrs engine type was painted on the rudder, on all silver painted planes.

Small black Ikarus factory logo was painted on both tailplane sides, on silver and camouflaged planes. Also, the sole service inscription on the IK-2 was a small, black “DIZI OVDE” (Lift Here) placed on the rear fuselage bottom position, just above protruding hole for IK-2 rear fuselage manipulation on the airfield. Nenad M. Miklusev C.2010/2011.

A group of soldiers posing in front of Ikarus IK-2 No. 2107-White 31 in a hangar at the airfield Borongaj-1940s. Another Ikarus Ik-2, white 34 - No. 2110 can be seen in the background. Both belong to the 107th Squadron 34th Fighter groups, 4th Fighter regiment. Photo Relja Nedić via Dragan Kolundžić

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