Ikarus IK-3

[Milos Sijacki]

The Rogožarski IK-3, a low wing monoplane single seat interceptor fighter with retractable landing gear, was a product of the design team of Ljubomir Ilić and Kosta Sivčev as a follow on to their IK-1/IK-2 fighter. Joined by Ing. Zrnić, they initiated the design in 1936 under strict secrecy, wind tunnel testing was done in France, before submitting the design to the Yugoslav Air Ministry. Construction of the IK-3 was assigned to Rogožarski A. D. in Belgrade and the prototype flew for the first time in the spring of 1938.
Artist vision of encouter between IK-3 and Me
Artist vision of encouter between IK-3 and Me

The IK-3 was powered by a Hispano-Suiza 12Y-29 liquid-cooled inline engine that was rated at 890 hp for take-off and at 920 hp at 11,810 feet altitude. The prototype was armed with one 20 mm Hispano-Suiza HS-404 cannon and two 7.92 mm FN-Browning machine guns mounted over the engine in the fuselage. The aircraft was of mixed steel tube, wood, and fabric construction with the retractable landing gear of Messier design. Its construction was similar to Hawker Hurricane.
Pilots of 51st fighter group in Zemun airport 1940,behind pilots is IK3 fighter.
Pilots of 51st fighter group in Zemun airport 1940,behind pilots is IK3 fighter.

Six test pilots flew the prototype in a very successful test program before it was lost. On January 19, 1939 the test pilot, Captain Pokorni, after a series of acrobatic maneuvers entered a terminal velocity dive from which he did not recover. After an investigation the aircraft was found not at fault and the Air Ministry ordered an initial lot of twelve aircraft.

The production IK-3 was refined with a number of changes including modifications to the sliding cockpit canopy, addition of a bullet proof windshield, and installation of the Avia H.S. 12Ycrs inline engine, a Czech built version of the Hispano-Suiza installed in the prototype. The first IK-3s were delivered in the summer of 1940 to an experimental fighter squadron whose pilots preferred it to the Messerschmitt Bf 109E-3 and the Hawker Hurricane, as the IK-3 was more maneuverable and could make tighter turns. Additionally, the aircraft was found to be very maintainable.

With the success of the IK-3, planning began for licensing manufacture in Turkey as well as increased production by Rogožarski. But before the second lot of IK-3 could be started German forces invaded Yugoslavia.

As production of the IK-3 proceeded the design team was working on improved versions of the IK-3 and other designs. Among the IK-3 improvements in work was installation of a more powerful engine. Engines that were considered to various extents were an upgraded 1,100 hp Hispano-Suiza 12Y-51, the Daimler-Benz DB-601A, and the 1,030 HP Rolls-Royce Merlin III engines. Also, Rogožarski was pursuing a new fighter design, the IK-5, that was to be powered by two Hispano-Suiza 12Y engines. Two versions of the design were planned, a single seat interceptor and a two seat long range "destroyer" with heavy nose mounted armament. Models of the IK-5 had been tested in wind tunnels and construction of a prototype begun when the German invasion ended this and all other efforts.

At the beginning of the April war, only 6 out of 12 IK-3 from the first production series were operational. One aircraft was lost in an air accident before the war, four were in workshop on scheduled services and repairs and one aircraft was undergoing modification to Series II IK-3 standard in Rogozarski airplane factory. Six remaining IK-3s were allocated to 161st and 162nd fighter squadron (3 IK-3 each) of the 51st Fighter group. 51st fighter group was part of the 6th fighter regiment of Royal Yugoslav Air Force which was tasked to defend Yugoslav capital, Belgrade. Both fighter squadrons were stationed at Zemun airport.

Operators

* Kingdom of Yugoslavia

General characteristics

* Crew: one, pilot
* Length: 27 ft 5 in (8.38 m)
* Wingspan: 33 ft 10 in (10.33 m)
* Height: 10 ft 8 in (3.23 m)
* Wing area: 179 ft² (16.6 m²)
* Empty: 4,123 lb (1874 kg)
* Loaded: 5,291 lb (2405 kg)
* Maximum takeoff: lb (kg)
* Powerplant: 1× Avia-built Hispano-Suiza 12Ycrs twelve cylinder Vee liquid-cooled engine, 920 shp (686 kW) each


Performance

* Maximum speed: 327 mph at 17,715 ft (526 km/h at 5401 m)
* Range: 310 miles (496 km)
* Service ceiling: 26,250 ft (8,003 m)
* Rate of climb: ft/min (m/min)
* Wing loading: 29 lb/ft² (113 kg/m²)
* Power/mass: 0.17 hp/lb (0.29 kW/kg)

Armament

* 1× 20 mm Hispano-Suiza HS-404 cannon
* 2× 7.92 mm FN-Browning machine guns

 

[Aggie08]

Cool, never heard of it before. I googled it, here are some pics.

IK

 

[mkloby]

Good post, milos. A lot of people haven't heard of the aircraft. Definitely a great success of Yugoslav industry, although cut short.

 

[Watanbe]

Nice, thanks for posting that I hadn't heard of it either. THe plane looks like the offspring of a Hurricane and Dewontine!!

 

[Milos Sijacki]

Thanks guys. This plane actually was designed around Hurricane which served in RYAF. There were also plans to power the later types of this airplane with Daimler-Benz engines. This was a good fighter, but German fighter pilots were all veterans, so it wouldn't do much good anyway.

 

[Watanbe]

Thanks guys. This plane actually was designed around Hurricane which served in RYAF. There were also plans to power the later types of this airplane with Daimler-Benz engines. This was a good fighter, but German fighter pilots were all veterans, so it wouldn't do much good anyway.

Yeh and no way could they get enough in the air to pose an real threat to the Germans! Was the design ever considered by any other Nations??

 

[imalko]

...This was a good fighter, but German fighter pilots were all veterans, so it wouldn't do much good anyway.

In April War of 1941 Yugoslav IK-3 pilots shot down four German aircraft and claimed one probable. One Yugoslav pilot was killed in action and two wounded.(Source: "Naša krila" magazine)

Yeh and no way could they get enough in the air to pose an real threat to the Germans! Was the design ever considered by any other Nations??

Low production rate and production in small limited series plagued Yugoslav aircraft industry throughout the existence of Yugoslav Kingdom. I think that IK-3 was never considered by other nations, but one captured example was tested by the Luftwaffe at Rechlin. However, after the war new fighter was developed - Ikarus S-49A (picture 2 in attachment) and its advanced version S-49C - and these were based on prewar Rogožarski IK-3.

First prototype of IK-3 (picture 4) had different wind screen and was painted overall gray and with pronounced national markings including large national flag painted on the rudder. IK-3s of serial production (only 13 examples build) were painted with camouflage colors and low visibility national markings adopted by Royal Yugoslav Air Force (RYAF) for front line aircraft (picture 1 and 3).

 

[Waynos]

Thanks guys. This plane actually was designed around Hurricane which served in RYAF. There were also plans to power the later types of this airplane with Daimler-Benz engines. This was a good fighter, but German fighter pilots were all veterans, so it wouldn't do much good anyway.

Do you mean structurally? Externally it looks much closer to the Dewoitine in the side profiles, and my oh my, with the bubble hood doesn't it resemle a Yak!

 

[imalko]

.... There were also plans to power the later types of this airplane with Daimler-Benz engines.

Here's one drawing of Daimler-Benz powered Ik-3 project (see the atachment) and also a link for more info on Rogožarski Ik-3: IK-3_intro

 

[LWulf]

In the fight it was hell flying the IK-3 since LW pilots could easily make out its shape, unlike for other Yugoslav pilots flying Bf 109s, which were usually only attacked after starting attacks on LW aircraft.

It's been a while since I've read "Zapisani nebu", a book on Slovenian combat pilots, but I remember them saying that while the IK-3 had lighter controls and tighter turning circle it was outperformed by the Bf 109. One pilot commented on this saying they preferred the IK-3 because of the few mock dogfights they had flying IK-3 versus the Bf 109. Not knowing any better they only turned around until getting on the tail of the other guy. The pilots emphasised many times their lack of experience in combat flying, so I am not surprised that they preferred the IK-3 over the Bf 109 E, despite the difference in performance.
From what I gathered the IK-3 was slightly slower than the Hurricane and climbed similarly, but had more responsive controls and better weapons (I guess they meant the cannon and its placement vs wing mounted MGs). I also remember that the IK-3 didn't have radios? Not sure about this tho.
IMHO the IK-3 was not on par with the contemporary fighters, despite the best efforts of the engineers behind it. :/ I still like its looks tho.

A bit offtopic, but for a while I hoped that we might get an IK-3 in the il2 game, since there were other "only one built" aircraft, but il2 devs said that unless a user makes it they had no plans to make it. Oh well.
I remember that in the "Freebirds" sim they had a recreation of the battle over Belgrade with Yak-1s and/or Hurricanes replacing the IK-3s. Must've been nice.

Anyway, it's good to see that this aircraft and the brave men flying it are not completely forgotten.

 

[Shortround6]

Do you mean structurally? Externally it looks much closer to the Dewoitine in the side profiles, and my oh my, with the bubble hood doesn't it resemle a Yak!

It looks like it was much more of a development of the Ikarus IK-2. The fabric covered rear fuselage was not uncommon at the time ( and easier to make). If you are using a Hispano V-12 engine the nose of the aircraft is probably going to be similar to other Hispano powered aircraft unless the designer really mucks things up. If it was designed in with help from a French wind tunnel then the similarity to French aircraft is easy to understand.

 

[papa_bear]

Hello, I'm sorry for digging up this topic, but...
New model in 1/72 scale is on the market soon. Producer is AZ Models.
We still don't know is it shape good, but we know that painting instruction is very big What IF!
If you want to build good IK3, accurate model, with realistic paintjob, please do not use any drawing or profile from guy Srecko Bradic... All of his profiles are not accurate. Mostly are what if again.
I'm not supporting Nenad Miklusev, but his work is accurate nearly100%
If you want to build good Ik fighter, visit this site. Linky: IK-3_intro
Sry if I was boring...
Happy modelling,
Dada

 

[imalko]

I was really hoping this won't be mentioned, but since it was here is a short explanation of Dada's post...
You see, there is unresolved copyright issues (which will probably see their epilogue on the court) between few Serbian authors of whom some had published works on IK-3 both in Serbian and foreign magazines. Likewise there is bitter rivalry between profile artist about whose profiles are more accurate and so on. There's no need for me to emphasize here how difficult it can be to interpret black&white photos correctly. But in my opinion this dispute (which is raging for a while now as can be seen on some Serbian aviation forums for example) is completely unnecessary. Instead of accusing each other on whose profile work is accurate or not, they should really discuss it together and try to interpret photos the best way possible and with other available data on colors used,etc came up with as accurate color profiles as possible. This would only benefit everyone.

Appearance of new IK-3 kit in 1/72 scale on the market is great news and I'm first to welcome it as such. Hope this will be accurate and good kit for enjoyment of scale modelers everywhere.

Ok, I'm done with off topic. The real purpose of this thread is to share information and discuss the Rogožarski IK-3 fighter with our forum friends from other countries. Along those lines here are few pictures taken from book "Ilustrovana istorija vazduhoplovstva".

Picture 1: First prototype of IK-3 which was destroyed during flight testing on 19th January 1939. Note the rounded one-piece windscreen which was later changed on production models.
Picture 2: Design team behind IK-3 fighter: (from left hand) Slobodan Zrnić, Ljubomir Ilić and Kosta Sivčev
Picture 3: Production model of Rogožarski IK-3 at Belgrade airport in 1940. The aircraft was armed with Oerlikon 20mm motor cannon and two synchronized machine guns Browning 7,92mm.
Picture 4: Instrument panel of the production model of IK-3.

 

[imalko]

And few more also taken from book "Ilustrovana istorija vazduhoplovstva"...

Picture 1: Pilots of 51st Fighter Group of Royal Yugoslav Air Force in front of one production model IK-3 at Belgrade airport in 1940.
Picture 2: Three view color drawing of Rogožarski IK-3. (Artist: Danijel Frka)

 

[imalko]

This Day 71 Years Ago - Crash of IK-3 Prototype

On this day, 19th January 1939, Yugoslav test pilot Captain Milan Pokorni tragically ended his life when he crashed during a test flight with prototype of Rogožarski IK-3 fighter aircraft.
After successfull initial test flights prototype of IK-3 was transferred from Test group ("Opitna grupa") to the 6th Fighter Regiment where further test were to be conducted. On 19th January it was planned to test the plane in full throttle sharp turns. First flight on that day was made by Col. Dragutin Rubčić, commanding officer of the Regiment. Flight ended with rough landing in spite of pilot's great experience. Plane struck hard to the ground with starboard landing gear leg, bounced off and then landed roughly. The plane was immediately examined by Ing. Marko Radosavljević from Rogožarski factory. With no apparent damage second flight on that day was authorized with Cpt. Pokorni in the cockpit. At the end of flight while returning to the airfield and probably in an effort to make high speed low level pass Captain Pokorni dived with IK-3 at high speed above the airfield. At one moment starboard wing broke off and aircraft crashed at the edge of the airfield killing the pilot.
Subsequent investigation concluded that wing structural failure occurred due acumulated damage on the wing spar near to the wheel bays caused by number of rough landings during testing. Test pilot Cpt. Milan Pokorni was buried at Novi Sad.

Compiled by Nenad Miklušev - Translated by imalko

Picture 1: Captain Milan Pokorni

Picture 2: Prototype of IK-3 with Captain Milan Bjelanović in the cockpit.

Picture 3: Starboard wing at the crash site.

 

[JOEJAN]

Well you probably didn't know they were planning to build IK5,but the war started,just as in 1991 for NOVI AVION... (
IK5 would probably be the best fighter in WWII,please don't sheet German planes are the best,SIZE OF THE COUNTRY DOESN'T MATTERS!
IK3 could compare to the best fighters at the beginning of the WWII,but it was outnumbered,and they didn't put fire munition on them(fools)...
IK5 pics:

 

[tomo pauk]

...
IK5 would probably be the best fighter in WWII,please don't sheet German planes are the best,SIZE OF THE COUNTRY DOESN'T MATTERS!...

Excuse me, expert, what are the best planes?

 

[imalko]

Bottom line is you can't compare aircraft which never left the drawing board to the types which saw large scale service during the war. One could argue that IK-5 had potential to be among the best twin engined fighters of the time, but since the design was never build we will never know.

I fail to see what IK-5 has to do with thread dedicated to Rogožarski IK-3 though.

 

[Knegel]

Hi,

the IK-3 had very much the same specs like the MS405 and even the same engine and it looks like a hybrid of the Hurri and MS405. I guess the performence also was very similar.

Rather smal wings with an high aspect ratio and a light body. I bet with an DB601A it would have been a great high alt fighter. Though, the light weight must have had some bad drawbacks(no radio??, bad armor, self sealing tanks?? Smal amo load??).

Greetings,

Knegel

 

[VG-33]

Hi,

the IK-3 had very much the same specs like the MS405 and even the same engine and it looks like a hybrid of the Hurri and MS405. I guess the performence also was very similar.

I hope for Yougos it wasn't so. MS-405 never exceeded 450 km/h, and Hurry was a big peace of cake; it's performance was mostly due to it's 1030 hp Merlin rather to the very roomy airframe and thick wings.

With the same Hispano 880 hp power it's performance would have certainly been pityfull. So the IK-3 airframe was better than both of theese and should be compared to the very improved MS-410 (510 km/h).

Rather smal wings with an high aspect ratio and a light body. I bet with an DB601A it would have been a great high alt fighter. Though, the light weight must have had some bad drawbacks(no radio??, bad armor, self sealing tanks?? Smal amo load??).

Why high alt? The low power request generated by high aspect ratio and a light wing loading plays a rule at any hight to outclimb or outfight in turning circles the same (what if) powered Me-109.

I don't think that IK-3 technology was more advanced that the Hurricane's, Bf-109's and MS-406 one's, but at least it was cleverly concieved (i mean optimised for it's low available power).

Like the french D-520, D-550, VG-33, soviet I-17, I-18, Czekh Avia B-135 and the rest of the unlucky underrated family...

Regards

VG-33