The Ikarus 451 is a family of research aircraft designs built in Yugoslavia in the 1950s, all sharing the same basic airframe, but differing in powerplants and cockpit arrangements.

[1] To research prone pilot cockpit arrangements and controls, the Government Aircraft Factories developed the Ikarus 232 Pionir, a small twin-engined low-wing monoplane, powered by 2x 48 kW (65 hp) Walter Mikron III piston engines.

[1] An enlarged version of the Pionir was developed as the Type 451, powered by 2x 120 kW (160 hp) Walter Minor 6-III piston engines.

This flew in 1952, and by the end of the year was followed by the 451M (Mlazni – "Jet") which had conventional seating for the pilot and in place of the two Walter Minor 6-III inline engines of the original Ikarus 451 (which has two inverted Walter six-cylinder piston engines of 120 kW (160 hp) each, 6.7 m (22 ft) wingspan, a maximum speed of 335 km/h (182 knots) and a ceiling of 4750m (15,570 ft).)

This differed from preceding designs in having a tricycle undercarriage, as well as Turbomeca Marbore engines with over twice the thrust of those used on earlier aircraft, and armament increased to two HS.404 cannon carried under the fuselage.