S, 'Sparka' V.F.Bolkhovitinov

12k b/w photo from the "History of aircraft construction in the USSR" by V.B.Shavrov, Vol.2 p.55

H
igh speed close support bomber. It combined power of twin-engine aircraft with low drag of a classic single-engine scheme.
The S had a very long, slender fuselage that contained two engines in tandem ('sparka') in front of the wing, each driving part of a six-bladed contra-rotating propeller. The 'greenhouse' cockpit with the two seats was well aft of the small wing.
Unique powerplant ('sparka') was developed and tested prior to the aircraft. It was pretty simple and efficient, but added 150kg of weight.
Electric control systems were used widely (unusual for Soviet pre-War aircraft), including remotely controlled machineguns in the very tail.
With one engine removed, 12k b/w photo from the "History of aircraft construction in the USSR" by V.B.Shavrov, Vol.2 p.55

Whole metal aircraft incorporated several novel solutions (especially in wing and fuselage construction), which will be found useful decade later in such aircraft as Il-28. Wing was equipped with large flaps to simplify landing - wing load of 225kg/m2 was a record high. During flight test wing airfoil had to be modified, and it was performed on same wing by adding 'second skin'. Some tests were carried out with second engine removed.
Flown in 1939-1941, 'S' remained experimental and did not enter production because Pe-2 was already in production at the same factory.
64k drawing from same source used to make a background;
Sources :
  • "History of aircraft construction in the USSR" by V.B.Shavrov, Vol.2 p.53-56
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  • S, Bolkhovitinov
    		• Technical data
    Type 'S''Sparka'
    Function Experimental
    Year 1939 1940
    Crew 2?
    Engines 1*960hp M-103 2*960hp M-103
    Length 13.0m 13.2m
    Wingspan 12.2m 11.4m
    Wing area 23.4m2 22.9m2
    Loaded weight 4000kg 5150kg
    Wing load 171kg/m2 225kg/m2
    Power load 4.2kg/hp 2.7kg/hp
    Speed at 0m 332km/h -
    Speed at 4500m 400km/h 570km/h
    Armament
    Guns 1*7.62mm ShKAS or 2*12.7mm UB
    Modified June 3, 1997
    by Alexandre Savine;    		 Back to
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