 Complete the following phrase:  Early helicopter gunships also operated in the side-firing configuration, an early example being the Aérospatiale Alouette III. During the Overseas wars in Africa in the 1960s, the Portuguese Air Force experimented to install M3 Browning .50 caliber machine guns in a side-firing twin-mounting configuration in some of its Alouette III helicopters. Later, the .50 caliber machine guns were replaced by a MG 151 20mm cannon in a single mounting. These helicopters were known in Portuguese service as helicanhões heli-cannons and were used in the escort of unarmed transport helicopters in air assault operations and in the fire support to the troops in the ground. The South African and Rhodesian air forces later used armed Alouette III in similar configurations as the Portuguese, respectively in the 