Mikoyan I-7K interceptor
The USSR had a substantial challenge in defending the vast Soviet airspace frontier, especially as the performance of threat aircraft increased. Among the large interceptor projects of the 1950s was Mikoyan's I-3P, a swept-wing design powered by a single Klimov VK-3 and armed with two 30mm cannon and the capability to carry unguided rockets. Problems with the VK-3 kept the I-3P prototype from being finished as planned, but this airframe was converted to take the Al-7F engine as the I-7. This was intended to lead to an I-7U tactical fighter that would have been accompanied by an I-7K interceptor variant fitted with the Almaz-3 radar and armed with K-6 AAMs. Testing with the I-7 showed a disappointing performance, and no series production of either model would be undertaken.