Il-4, Pe-2 and Tu-2 would be my choices.
Medium bombers only, then. Bearing in mind the desire for level bombing.
Ok, deserves a look.
In 1938, the Ilyushin design bureau redesigned the Ilyushin DB-3 to ease production and improve performance, the revised version receiving the designation DB-3F (Forsirovannyi or "boosted"). The aircraft's internal structure, particularly the wings, was extensively changed, eliminating the need for hand finishing of the structure and with Duralumin replacing the large scale use of steel in the earlier aircraft.[2][3] The aircraft's fuel system was redesigned, increasing capacity while reducing the number of fuel tanks.[2] The fuselage nose was lengthened to give more room for the navigator/bomb-aimer while reducing drag. The prototype DB-3F, powered by the same 708 kW (949 hp) Tumansky M-87B engines of the DB-3M, was piloted on its maiden flight by Vladimir Kokkinaki on 21 May 1939.[4] It successfully passed through state acceptance tests and entered production in January 1940, with the 1,100 hp (820 kW) Tumansky M-88 quickly replacing the M-87.[5][6] The DB-3F was redesignated Il-4 in March 1942.[6] Some series had wooden outer wings and front fuselage to conserve metals, and throughout the production engines and fuel tanks were upgraded for more performance while keeping the same range. However the most notable change was the addition of larger defensive guns in the turret, using the 12.7 mm (0.5 in) UBT machine gun in place of the earlier 7.62 mm (0.3 in) weapons. In addition it was found that the gunners were attacked first, so blocks of armor were placed around the gunner positions.
All this extra weight wasn't offset by the newer engines however, and the Il-4 proved to be slower than the earlier versions at only 404 km/h (251 mph). An attempt to improve performance was made as the Il-6, adding large diesel engines and heavier armament. The engine proved unreliable and production was never started. The Il-4 remained in production until 1944, when just over 5,200 had been built.
Operational history
Although the Il-4 was only a medium bomber, it had the range to be used on strategic missions. The VVS wasn't terribly interested in this role, but nevertheless the Il-4 was used on several highly publicized raids against Berlin. Most would be used on much shorter range missions, often adding another 1,000 kg (2,204 lb) of bombs under the wings, in addition to the internal 2,500 kg (5,512 lb).
Finland bought four captured DB-3Fs from German stocks. These were given the Finnish Air Force serials DF-22 to DF-25 and flown from Bryansk, Russia to Finland (one aircraft, DF-22, was destroyed en route and crashed near Syeschtschinskaya airfield). The aircraft were later flown by No. 48 Sqn during 1943 (DF-23, DF-24 and DF-25), No. 46 Sqn during 1944 (DF-23 and DF-24) and No. 45 Sqn for a short time in 1945 (DF-23), until the last remaining serviceable aircraft went into depot on February 23, 1945. After the war, DF-25 got lost in snowbliz, landed on the ice and crashed into the woods in Öja near the city of Kokkola. Most parts of the plane were rescued and taken to a depot.[7]
^ a b Air International May 1986, p. 133.
^ Gunston 1995, pp. 100–101.
^ Gordon, Komissarov and Komissarov 2004, pp. 91–92.
^ Gordon, Komissarov and Komissarov 2004, p. 92.
^ a b Gunston 1995, p. 102.
^ Keskinen et al. 1982, p. 79,94.
Performance
Maximum speed: 410 km/h (255 mph; 221 kn) at 6,500 m (21,325 ft)
Range: 3,800 km (2,361 mi; 2,052 nmi) (max internal fuel), 2,600 km (1,404 nmi; 1,616 mi) with 1,000 kg (2,200 lb) bombs
Service ceiling: 8,700 m (28,543 ft)
Time to altitude: 13.6 min to 5,000 m (16,404 ft)
Armament
Guns: * 2 × 7.62 mm ShKAS machine guns (1 in nose, 1 in ventral hatch)
1 × 12.7 mm UBT machine gun in dorsal turret
Rockets: 2 × BETAB-750DS 305 mm rockets.[11]
Missiles: 1 × 940 kg (2,100 lb) Type 45-36 torpedo[10]
Bombs: Up to 2,700 kg (6,000 lb) of bombs or mines.
http://en.wikipedia.org/wiki/Ilyushin_Il-4Or
Pe-2 .... dive bomber
Or ....
Tupolev Tu-2
The Tupolev Tu-2 (Development names ANT-58 and 103, NATO reporting name: Bat) was a twin-engine Soviet (high) speed daylight bomber (SDB) front line bomber (FB) aircraft of World War II vintage. The Tu-2 was tailored to meet a requirement for a high speed bomber or dive-bomber, with a large internal bomb load, and speed similar to that of a single seat fighter. Designed to challenge the German Junkers Ju 88, the Tu-2 proved comparable, and was produced in torpedo, interceptor and reconnaissance versions. The Tu-2 was one of the outstanding combat aircraft of World War II and it played a key role in the Red Army's final offensives.[1]
Design and development
In 1937 Andrei Tupolev, along with many Soviet designers at the time, was arrested on trumped-up charges of activities against the State. Despite the actions of the Soviet government, he was considered important to the war effort and following his imprisonment, he was placed in charge of a team that was to design military aircraft. Designed as Samolyot (Russian: "aircraft") 103, the Tu-2 was based on earlier ANT-58, ANT-59 and ANT-60 light bomber prototypes.[2] Essentially an upscaled and more powerful ANT-60 powered by AM-37 engines, the first prototype was completed at Factory N156, and made its first test flight on 29 January 1941, piloted by Mikhail Nukhtinov.[2] Mass production began in September 1941, at Omsk Aircraft Factory Number 166, with the first aircraft reaching combat units in March 1942. Modifications were made based on combat experience, and Plant Number 166 built a total of 80 aircraft. The AM-37 engine was abandoned to concentrate efforts on the AM-38F for the Il-2, which required Tupolev to redesign the aircraft for an available engine. Modifications of this bomber took ANT-58 through ANT-69 variants. A further 2527 aircraft were built at Kazan, with these modifications. Production ceased in 1951 after a total of some 3,000 aircraft were delivered to various Soviet Bloc air forces.[1]
Operational history
Built from 1941 to 1948, the Tu-2 was the USSR's second most important twin-engine bomber (the first being the Pe-2). The design brought Andrei Tupolev back into favour after a period of detention. It was highly effective, being faster and more nimble, as well as having a greater bomb load and range, than virtually all medium bombers in service during the war with any army. Crews were universally happy with their Tupolevs. Pilots could maneuver like fighters and they were fast and tough enough to survive heavy damage.[3] The Tu-2 remained in service in the USSR until 1950.
Some surplus Tu-2s were provided to the Chinese People's Liberation Army Air Force for use in the Chinese Civil War. Some Chinese Tu-2s were shot down by British and American airmen during the Korean War. In the 1958–1962 counter-riot actions in Qinghai-Tibet Plateau covering Qinghai, Tibet, southern Gansu, and western Sichuan, Chinese PLAAF Tu-2s took on the roles of ground-attack, reconnaissance and liaison. The Chinese Tu-2s were retired at the end of 1970s.
After World War II, the Tu-2 proved to be an ideal test aircraft for various powerplants, including the first generation of Soviet jet engines.[1]
Performance
Maximum speed: 521 km/h (281 kn, 325 mph)
Range: 2,020 km (1,090 nmi, 1,260 mi)
Service ceiling: 9,000 m (29,528 ft)
Rate of climb: 8.2 m/s (1,610 ft/min)
Wing loading: 217 kg/m² (45 lb/ft²)
Power/mass: 260 W/kg (0.16 hp/lb)
Armament
Guns:
2 × 20 mm (0.79 in) fixed forward-firing ShVAK cannon in the wings
3 × 7.62 mm (0.30 in) rear-firing ShKAS machine guns (later replaced by 12.7 mm (0.50 in) Berezin UB machine guns) in the canopy, dorsal and ventral hatches.
Bombs: 1,500 kg (3,300 lb) internally and 2,270 kg (5,000 lb) externally
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Between those 3, I'd say the TU-2 is the most important based on the best is better rule.
But bear in mind I also recommended the Pe-2 alongside. Guess if 2 VVS medium bombers are
added, who could have issue with the best two?
(Although, I have to admit, the SB-2, though older and more antiquated, opens up a bomber
for SCW in the AvA and events.
)