BOLKHOVITINOV S
place this by twin 12.7mm UBT. Behind the rear spar, under the pilot's cockpit, was a bay housing 400kg (882 Ib) of bombs, with two electrically driven doors. It was the intention later to fit fixed guns in the wings. The second wing, of NACA-230 profile, gave improved field length. One report states that a remotely controlled ShKAS was added in the extreme tail, but this does not appear in any known photographs. Continued potentially dangerous problems with the rear engine and its drive resulted in this being removed. The front engine was changed to an M-l 05P, of unchanged 960hp, driving a single three-blade propeller. Even with weight considerably reduced the S was then judged a failure, though tandem-engine studies continued. The factory was tooled up for Pe-2 production.
Though an article by Ing V Mikhailov and Ing VPerov states that, following initial Nil testing 'the design team was instructed to continue development', there is no doubt the S was always on the verge of success but never getting there. The high wing loading and the failure to solve the rear-engine drive problem made it one of the programmes abandoned after the invasion of June 1941.
Dimensions Span (original) (new wing) Length (original) (one engine) Wing area (original) (new wing)
11.38m 12.2m 13.2m 13.0m 22.9 m2 23.43m2
37 ft 4 in 40 ft X in 43 ft 4 in 42ft7 3 /iin 246.5ft2 252.2 ft2
S (as built)
S (as built). 50
S (as built).
Weights Empty not discovered Loaded (original) 5,652kg 1 2,460 Ib (lightened, to reduce take-off run) 5,150 kg 11 ,354 to (single engine) 4,000kg 8,818 Ib Performance Maximum speed (original) at 4,600m (15,092 ft) (oneM-105P) at 4,400m (14,436ft) Range (two engines) about Take-off run (original) (lightened) (one engine) Landing speed (original) (lightened) (one engine)
570km/h
354 mph
400 km/h 700km 1,045m 860m 700m 180 km/h 1 65 km/h 135 km/h
248.5 mph 435 miles 3,428ft 2,822ft 2,297 ft 112 mph 102.5 mph 84 mph