There was no further engine change in the Airacobra after the appearance of the P-39N model, the 1,325 hp Allison V-1710-85 twelve-cylinder liquid-cooled V-engine, but there were some differences in internal fuel tankage among the early P-39Qs, the P-39Q-1-BE having 87 gal (329 l), the P-39Q-5-BE having 110 gal (416 l), and the P-39Q-10-BE and subsequent versions reverting to the 120 gal (454 l) of previous versions. In the P-39Q-20-BE batch various types of airscrew were fitted, the P-39Q-21 and P-39Q-25-BE having four-bladers, although the P-39Q-30-BE reverted to the three-blader as tests indicated that directional stability was materially worsened by the four-blader without any commensurate gain in performance.
One of the last USAAF units to receive the Airacobra was the 332nd Fighter Group which took 75 P-39Qs to the 15th Air Force in Italy in February 1944. No less than 4,905 P-39Qs had been completed when Airacobra production finally terminated in August 1944, the bulk of which were supplied to the Soviet Union, including the aircraft above, pictured before delivery. In fact, of the 9,558 Airacobras of all types produced during the production life of this fighter, 4,924 were allocated to the Soviet Union, 4,758 of these reaching their destination. The Airacobra was popular with the Russians who appreciated its close-support capabilities. 165 Airacobras were also supplied to the Free French, and the peak USAAF inventory of this fighter was 2,105 machines in February 1944, although by the following August all first-line groups had re-equipped with later types.
Span: 34 ft 0 in (10.36 m)
Length: 30 ft 2 in (9.19 m)
Height: 12 ft 5 in (3.78 m)
Wing area: 213 sq.ft (19.79 sq.m)
Empty weight: 5,645 lb (2,560 kg)
Loaded weight: 7,600 lb (3,447 kg)
Max loaded weight: 8,300 lb (3,765 kg)
Max speed: 330 mph (531 kmh) at 5,000 ft (1,524 m)
Max speed: 357 mph (575 kmh) at 10,000 ft (3,048 m)
Max speed: 376 mph (605 kmh) at 15,000 ft (4,572 m)
Climb: to 5,000 ft (1,524 m) 2 min
Climb: to 10,000 ft (3,048 m) 4 min
Climb: to 20,000 ft (6,096 m) 8 min 30 sec
Service ceiling: 35,000 ft (10,668 m)
Range, clean: 525 mls (845 km) at 10,000 ft (3,048 m) at 250 mph (402 kmh)
Range, 175 gal (662 l) droptank: 1,075 mls (1,730 km) at 195 mph (314 kmh)."