R3

R3, R.III or R-3 or R/3 may refer to:

R-3 (tank)

R-3 was a proposed Romanian tank design for use in World War II. It was basically a variant of the Czechoslovak S-II-c tank prototype (known as the T-21 tank after 1939) which was going to be built in Romania because of the repeated acquisition failures. Because of political reasons and the limited industrial capacities of both Škoda Works and the Romanian industry, the design never entered production.

History

In the summer of 1940, Romania's traditional interwar arms delivery partners, France and Czechoslovakia, were under German occupation. Romania's armored forces were equipped with 126 light R-2 tanks, 75 Renault R-35 tanks (41 of which were interned Polish tanks), 35 R-1 tankettes and 75 obsolete Renault FT tanks. As the country was basically surrounded by hostile neighbours from all sides and the Renault R-35 tank deliveries were stopped, the Romanian Army sought to buy a medium tank.

The chosen design was the Czechoslovak S-II-c prototype, the successor of the LT vz. 35 light tank. The Romanian trials and field testing of the tank started in late 1939. This choice came naturally, as Romanian troops were already familiar with its predecessor. The prototype was later designated by Škoda Works as the T-21 medium tank. Nazi Germany refused to deliver tanks to Romania because the country was not yet part of the Axis.

K-13 (missile)

The K-13 (NATO reporting name AA-2 Atoll) is a short-range, infrared homing air-to-air missile developed by the Soviet Union. It is similar in appearance and function to the American AIM-9 Sidewinder from which it was reverse-engineered. Although it since has been replaced by more modern missiles in front line service, it saw widespread service in many nations.

Background - the Sidewinder missile

During the Second Taiwan Strait Crisis in 1958, the Republic of China's (Taiwan) F-86 Sabres faced the much higher performance, mainland Chinese PLAAF MiG-17s. The MiGs had speed, maneuverability and altitude advantages over the Sabres, allowing them to engage only when they desired, normally at advantageous times. In response, the US Navy rushed to modify 100 of the ROC's Sabres to fit the newly introduced AIM-9 Sidewinder missile, the latest model being the "B" version. These were introduced into combat for the first time on 24 September 1958, when a group of MiG-17s cruised past a flight of Sabres, only to find themselves under attack by missile fire. This was the first instance of guided missiles being used in air-to-air combat.