Ikarus IO

Ikarus IO
Role	Reconnaissance flying boat
National origin	Yugoslavia
Manufacturer	Ikarus
Designer	Josip Mikl
First flight	September 1926
Introduction	1927
Status	inoperable
Primary user	Yugoslav Royal Navy
Number built	38

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.

After the crash of the Ikarus IM prototype reconnaissance seaplane (Serbian Cyrillic:Икарус ИМ - Извиђач Морнарички) with 260 hp (190 kW) BMW IV engine, on 31 May 1926, Ikarus immediately started development of a second reconnaissance seaplane prototype powered by a 4–00 hp (3.0–0.0 kW) 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 monuting. Painted light gray, the aircraft were used in coastal reconnaissance and bombing roles and could carry about 250 kg (550 lb) of bombs and were armed with a 7.7 mm (0.303 in) Darne machine gun mounted on the gunner's Scarff ring.

Markings subtypes of these aircraft were fitted with engines, according to [1]:

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