The Airacobra had two main production variants, and the P-39N was one of them, with 2,095 units produced. It was powered by a V-1710-85 engine that had a 1,200 horsepower output. The first 166 production aircraft had Aeroproducts propellers that were 10 feet and 4 inches (3.15 meters) in diameter and were equipped with twelve wing fuel tanks that had a combined capacity of 120 US gallons (454 liters). Subsequently, the Aeroproducts propeller was augmented to an 11-foot and 7-inch (3.53-meter) diameter, and four of the wing fuel tanks were removed to reduce the overall weight. This decreased the internal fuel capacity to 87 US gallons (329 liters). The P-39N-5-BE was the last block of aircraft produced and featured several improvements, including an SCR-695 radio, modified armor, bullet-proof glass behind the pilot, and a new oxygen system. Many P-39N planes were converted to ground support variants, with 35 P-39N-0-BEs converted to P-39N-3-BE, 128 P-39N- I-BEs converted to P-39N-2BE, and 84 P-39N-5-BEs converted to P-39N-6-BE. It’s worth noting that an order for 205 additional P-39N planes was cancelled.