Rogožarski SIM-XV / R-313
In connection with the growing danger of war in the second half of the thirties Yugoslavia started to carry out intensive work on designing new types of modern combat aircraft. Specifically, multi-purpose aircraft, which can be used as a light bomber, ground-attack aircraft and tactical explorer. Work to meet these requirements was begun by Ikarus and Rogožarskij.
In 1937 Rogožarski (Prva srpska fabrika aeroplana Rogožarski - Прва српска фабрика аероплана Живојин Рогожарски А. Д.) established a working group of engineer to proceed the project of a light twin-engine battle aircraft, designated R-313.
The Rogozarski R-313 (Рогожарски Р-313 in Serbian), originally called SIM-XV, was a two-seater twin-engined monoplane fighter/light bomber/reconnaissance aircraft. It was powered by two in-line Walter Sagitta IIR engines, both fitted with a compressor; each was capable of 493 hp. The inner fuel tank held 680 litres. The elliptical, wooden fuselage was covered in plywood which was also used to 'skin' the round-tipped, trapezoidal wings. The engine nacelles also housed the landing gear. The tail-wheel was, like the main landing gear, retractable. The fuel tank was located in the centre section between the wings. The reconnaissance variant of this aircraft was due to be equipped with a camera, a radio, a fixed 20mm cannon and a single FN 7.9mm machine gun, flexibly mounted. As a light bomber, the plane would carry four 106 kg 'Stankovic' bombs inside the fuselage. It was designed and built at the Rogozarski factory in Belgrade.
Construction of the prototype began in 1938 and completed at the end of next year. According to various sources, the first flight of the R-313 took place either at the end of 1939 or in July 1940. A total of 25 aircraft were planned, both reconnaissance and light bomber versions. In any case, the Sturmovik for the most part justified the hopes of the Air Force, whose specialists noted only the insufficient power of the engines. The engineers responded to the military's wishes, presenting soon the variants of the R-313 with Daimler-Benz DB-601 and Rolls-Royce Merlin engines. Both versions brought the aircraft to the level of foreign aircraft, but because of the German invasion of a number of European countries, deliveries of foreign-made engines became not possible.
The prototype became part of 603 training squadron which was located at Grab, near Trebinje during the April war. It was damaged and abandoned attempting to take-off from Grab on 12 April 1941. A month later, the Germans took control and sold the machine to the Croats who had taken over the 'Ikarus' factory. They renamed the aircraft "Независни" ("Independent"); after repairs, a test flight was carried out on 19 May 1942. Sabotage was then detected, so serious that further repairs could not be carried out. Thus ended the plane which was popular in literature as the "Yugoslav moskito" Although it was designed and built long before its legendary counterpart.
Engines: 2 × Walter Sagitta I-SR, 368 kW (493 hp) each
Propellers: 3-bladed Ratier
Wingspan: 13.00 m (42 ft 8 in)
Wing area: 26.40 m2 (284.2 sq ft)
Length: 11.00 m (36 ft 1 in)
Height: 2.68 m (8 ft 10 in)
Empty weight: 2,950 kg (6,504 lb)
Gross weight: 4,270 kg (9,414 lb)
Maximum speed SL: 376 km/h (234 mph; 203 kn)
Maximum speed 4000m/13,123ft: 460 km/h / 286 mph
Range: 1,000 km (621 mi; 540 nmi)
Service ceiling: 8,000 m (26,000 ft)
Rate of climb: 8.33 m/s (1,640 ft/min)
Time to 3000m / 10,000 ft: 5,7 min
Armament: 1x 20 mm (Oerlikon FF) HS-404 cannon, 1x flexible 7,92 mm Browning FN machine gun
Bombload: 400 kg / 882 lb