Ikarus IO
Biplane flying boat produced in Yugoslavia
title: "Ikarus IO" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["1920s-yugoslav-military-reconnaissance-aircraft", "flying-boats", "ikarus-aircraft", "biplanes", "single-engined-pusher-aircraft", "aircraft-first-flown-in-1926"] description: "Biplane flying boat produced in Yugoslavia" topic_path: "history/military" source: "https://en.wikipedia.org/wiki/Ikarus_IO" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Biplane flying boat produced in Yugoslavia ::
::data[format=table title="Infobox aircraft"]
| Field | Value |
|---|---|
| name | Ikarus IO |
| caption | Airplane Ikarus IO 2 |
| aircraft_type | Reconnaissance flying boat |
| national_origin | Yugoslavia |
| manufacturer | Ikarus |
| designer | Josip Mikl |
| status | retired |
| primary_user | Yugoslav Royal Navy |
| number_built | 38 |
| introduction | 1927 |
| first_flight | September 1926 |
| :: |
| name = Ikarus IO | logo = | logo_size = | image = | alt = | caption = Airplane Ikarus IO 2 | long_caption = | other_names = | aircraft_type = Reconnaissance flying boat | aim = | outcome = | related = | national_origin = Yugoslavia | manufacturer = Ikarus | design_group = | designer = Josip Mikl | builder = | issuer = | status = retired | owners = | primary_user = Yugoslav Royal Navy | more_users = | service = | major_applications = | proposals = | prototypes = | number_built = 38 | construction_number = | civil_registration = | military_serial = | radio_code = | requirement = | aircraft_carried = | flights = | total_hours = | total_distance = | construction_date = | introduction = 1927 | retired = | first_flight = September 1926 | initiated = | in_service = | last_flight = | expected = | developed_from = | variants = | developed_into = | preservation = | fate = | predecessors = | successors = | concluded = The Ikarus IO (Serbian Cyrillic:Икарус ИО – Извиђач Обални) was a biplane flying boat produced in Yugoslavia in the late 1920s. It was a conventional flying boat design for its day, featuring a large single-bay wing cellule, the staggered wings of slightly uneven span braced with N-struts. The pilot and observer sat side by side in an open cockpit, and a gunner sat in an open position ahead of them, in the bow. The pusher engine and frontal radiator were carried on struts in the inter-plane gap.
Development
::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/cd/Liberty_L-12-1.jpg" caption="A Liberty L-12, as installed in the Ikarus IO"] ::
After the crash of the Ikarus IM prototype reconnaissance seaplane (Serbian Cyrillic:Икарус ИМ – Извиђач Морнарички) with 260 hp BMW IV engine, on 31 May 1926, Ikarus immediately started development of a second reconnaissance seaplane prototype powered by a 4-00 hp Liberty L-12 engine, also designed by Josef Mikl, the Ikarus Technical Manager. The new prototype was named Ikarus IO (Coastal Reconnaissance) and the first test flight took place from the Danube at Novi Sad in September 1926.
After all-round tests, the aircraft was given a positive assessment and the Naval Air Force ordered the first series of 12 aircraft, which were delivered during 1927, serialled 101 to 112. Based on observations arising from the operational use of the aircraft, certain modifications were applied and another 24 modified IOs were ordered, receiving serials 113 to 136. In parallel with the development of the second IO series, Ikarus built prototype aircraft powered by a Loren engine.
The Ikarus IO was a flying boat with completely wooden structure, with wings rounded at the edges and covered with canvas. Auxiliary floats increased the stability of water-borne navigation. The two flight crew members, scout and pilot were seated side by side in parallel and the gunner sat in front of them in an open position with a Scarff ring gun mounting. Painted light gray, the aircraft were used in coastal reconnaissance and bombing roles and could carry about 250 kg of bombs and were armed with a 7.7 mm Darne machine gun mounted on the gunner's Scarff ring.
Variants
Markings subtypes of these aircraft were fitted with engines, according to [1]:
;IO/Li: Coastal Reconnaissance seaplane with 400 hp Liberty L-12, (36 copies + 1 prototype built the 1927th and 1928 when available). ;IO/Lo :Coastal Reconnaissance seaplane with 450 hp Lorraine-Dietrich 12Eb, (1 copy – a prototype conversion 1929th year) ;IO/Re :Coastal Reconnaissance seaplane with 500 hp Renault 12Ke(1 copy – the prototype of the 1930th year 1937), ;IO/Lo :Coastal Reconnaissance seaplane with 400 hp Lorraine Dietrich-12Db, (20 copies – Conversion 1934th year).
Operational history
The IO was used by the Kingdom of SHS / Yugoslavia Navy as a coastal reconnaissance seaplane and light bomber from 1927 until 1941. The aircraft were deployed and served at Divulje, Vodice and Kumbor. Initially the IO suffered a high accident rate and by 1932 only 29 of the 37 production aircraft were still in service. Because of intensive use the Liberty engines were worn out and difficult to support necessitating substitution with Lorraine-Dietrich engines. In January 1941, 4 aircraft remained in service, of which two were airworthy, which were not used in operations before being withdrawn.
Operators
;Kingdom of Yugoslavia
Specifications
|ref= |prime units?=met General characteristics
|genhide=
|crew=3 |capacity= |length m=10.4 |length ft= |length in= |length note= |span m=15.2 |span ft= |span in= |span note= |upper span m= |upper span ft= |upper span in= |upper span note= |mid span m= |mid span ft= |mid span in= |mid span note= |lower span m= |lower span ft= |lower span in= |lower span note= |height m=3.52 |height ft= |height in= |height note= |wing area sqm=47.5 |wing area sqft= |wing area note= |aspect ratio= |airfoil= |empty weight kg=1520 |empty weight lb= |empty weight note= |gross weight kg=2450 |gross weight lb= |gross weight note= |max takeoff weight kg= |max takeoff weight lb= |max takeoff weight note= |fuel capacity= |more general= Powerplant
|eng1 number=1 |eng1 name=Liberty L-12 |eng1 type=45° V-12 water-cooled piston engine |eng1 kw= |eng1 hp=400 |eng1 shp= |eng1 kn= |eng1 lbf= |eng1 note= |power original= |thrust original= |eng1 kn-ab= |eng1 lbf-ab=
|prop blade number= |prop name= |prop dia m= |prop dia ft= |prop dia in= |prop dia note= Performance
|perfhide=
|max speed kmh=170 |max speed mph= |max speed kts= |max speed note= |max speed mach= |cruise speed kmh=145 |cruise speed mph= |cruise speed kts= |cruise speed note= |stall speed kmh= |stall speed mph= |stall speed kts= |stall speed note= |never exceed speed kmh= |never exceed speed mph= |never exceed speed kts= |never exceed speed note= |range km=600 |range miles= |range nmi= |range note= |combat range km= |combat range miles= |combat range nmi= |combat range note= |ferry range km= |ferry range miles= |ferry range nmi= |ferry range note= |endurance= |ceiling m=4500 |ceiling ft= |ceiling note= |g limits= |roll rate= |climb rate ms= |climb rate ftmin= |climb rate note= |time to altitude= |lift to drag= |wing loading kg/m2= |wing loading lb/sqft= |wing loading note= |fuel consumption kg/km= |fuel consumption lb/mi= |power/mass= |thrust/weight=
|more performance= Armament
|armament= specific parameters, remove this parameter-- |guns= 1x 7.7 mm Darne machine gun in the bow gunners position |bombs= 250 kg |rockets= |missiles= |hardpoints= |hardpoint capacity= |hardpoint rockets= |hardpoint missiles= |hardpoint bombs= |hardpoint other=
|avionics=
Notes
References
- {{cite book | last = Лучић | first = Душан | script-title=sr:Основи практичне аеродинамике са описима аероплана | year = 1936 | publisher = Ваздухопловни Гласник | location = YU-Нови Сад | language = sr | id = | pages = | chapter =
- {{cite book | last = Микић | first = Сава Ј. | script-title=sr:Историја југословенског ваздухопловства | year = 1933 | publisher = Штампарија Д. Грегорић | location = YU-Београд | language = sr | id = | pages = | chapter =
- {{cite book | last = Оштрић | first = Шиме |author2=М. Мицевски | script-title=sr:Летећи Чунови: Чамци који лете – летјелице које плове | date = 2007 | publisher = Галерија '73 | location = SRB-Београд | language = sr | id = | pages = | chapter =
- {{cite book | last = Isaić | first = Vladimir |author2=Danijel Frka | title = Pomorsko zrakoplovstvo na istočnoj obali Jadrana 1918–1941. (prvi dio) | year = 2010 | publisher = Tko zna zna d.o.o. | location = Zagreb | language = hr | isbn = 978-953-97564-6-6 | pages = | chapter =
- {{cite journal | last = Петровић | first = Огњан М. | date = 2000 | title = Војни аероплани Краљевине СХС/Југославије (Део I: 1918–1930.) | journal = Лет – Flight | volume = 2 | publisher = Музеј југословенског ваздухопловства | location = YU-Београд | language = sr | issn = 1450-684X | pages = стр. 21–84
- {{cite book | last = Јанић | first = Чедомир |author2=Петровић, Огњан | script-title=sr:Век авијације у Србији 1910–2010, 225 значајних летелица | year = 2010 | publisher = Аерокомуникације | location = Београд | language = sr | isbn = 978-86-913973-0-2
References
- Петровић, Огњан М. (2/2000.). "Војни аероплани Краљевине СХС/Југославије (Део I: 1918 – 1930.)" (in (Serbian)). Лет – Flight (YU-Београд: Музеј југословенског ваздухопловства) 2: стр. 21–84. {{ISSN. 1450-684X
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