I would like to propose another interesting experimental construction from Pavel Sukhoi's bureau - Su-8.
Specifications (from Wikipedia):
General characteristics
Crew: 2
Length: 13.5 m (ft in)
Wingspan: 20.5 m (ft in)
Height: 5.11 m ()
Wing area: 60 m² (646 ft²)
Empty weight: 9,180 kg (20,240 lb)
Loaded weight: 12,425 kg (27,390 lb)
Max. takeoff weight: 13,380 kg (29,500 lb)
Powerplant: 2 × Shvetsov M-71F radial engines, 1,640 kW (2,200 hp) each
Performance
Maximum speed: 550 km/h (300 kn, 340 mph) at 4,600 m (15,090 ft)
Range: 1,450 km (785 nmi, 900 mi)
Service ceiling: 9,000 m (29,530 ft)
Rate of climb: 9 min to 5,000 m (16,405 ft)
Armament
4 × 37 mm (1.46 in) Nudelman N-37 or 4 × 45 mm (1.78 in) Nudelman N-45 cannon under the fuselage
8 × 7.62 mm (0.30 in) ShKAS machine guns (four in each wing)
1 × 12.7 mm (0.50 in) UBT machine gun in upper turret
1 × 7.62 mm ShKAS in lower turret
Total ammunition weight 232 kg (510 lb)
Up to 1400 kg (3,085 lb) of bombs
Some links:
http://en.wikipedia.org/wiki/Sukhoi_Su-8http://www.soviethammer.net/blog/494374-sukhoi-su-8/http://airwar.ru/enc/aww2/su8.html (In Russian)
http://www.aviastar.org/air/russia/su-8.phphttp://worldatwar.net/chandelle/v3/v3n2/su-8.html We can call this A/C 'Tank Buster' due to it's enormous cannons and machineguns battery. ;-)