The Yak-4 was an improved version of the Yak-2 with more powerful Klimov M-105 engines and a number of other changes that were made to try to rectify the problems of the Yak-2. Two additional fuel tanks were added in the outer wings to bring the total capacity up to 180 litres (40 imp gal; 48 US gal) and the gunner's canopy was bulged to give him more room to use his 7.62 mm (0.300 in) ShKAS machine gun. The upper fuselage was redesigned to improve the gunner's field of fire and the oil coolers were relocated from the sides of the engine nacelles to the 'chin' position to improve their performance.
SpecificationsGeneral characteristicsCrew: twoLength: 10.18 m (33 ft 5 in)Wingspan: 14.00 m (45 ft 11 in)Height: m (ft)Wing area: 29.4 m² (316 ft²)Empty weight: 4,560 kg (10,053 lb)Loaded weight: 6,115 kg (13,481 lb)Max. takeoff weight: kg (lb)Powerplant: 2 × Klimov M-105 V12 engines, 821 kW (1,100 hp each) eachPerformanceMaximum speed: 533 km/h (331 mph)Range: 925 km (548 miles)Service ceiling: 9,700 m (31,824 ft)Armament2 × 7.62 mm ShKAS machine gunsup to 600 kg (1,300 lb) of bombs
Yak-2 Yak-4first flight 1940 1940engine 2xM-103 2xM-105take-off power (hp) 2 x 960 2 x 1050length (m) 10,18 10,18wingspan (m) 14.00 14.00wing area (sm) 29.4 29.4empty weight (kg) 4258 4560gross weight (kg) 5630 6115speed at sea level (km/h) 410 458speed (km/h) 498 533at altitude (m) 4800 5050climb to 5000 m (min) 8.0 6.5service ceiling empty (m) 8700 9700operational range (km) 900 740takeoff run (m) 2 x 960 2 x 1050take-off power (hp) 390 442landing roll (m) 300 496bomb load (kg) 400-500 400-900armament 2x7.62 ShKAS 2x7.62 ShKAS[/td]