Bolkhovitinov S

Infobox Aircraft
name = S
type = Bomber
manufacturer =


caption =
designer = Viktor Bolkhovitinov
first flight = 29 January 1940
introduced =
retired =
status =Cancelled
primary user = Soviet Air Forces
more users =
produced =
number built = 2
unit cost =
variants with their own articles =

The Bolkhovitinov S was a Soviet bomber aircraft prototype of the 1940s, designed by Viktor Bolkhovitinov. The plane had no official designation, most commonly it is known as "S", which is sometimes developed as "Spartak" (Spartacus), "Sparka" (for paired engines) or "Skorost" ("speed"). There exist also designations for this plane: BBS, BB (Bolkhovitinov's Bomber), LB-S or SSS.

The plane was conceived as a fast light bomber and reconnaissance plane. To obtain high speed and good aerodynamics, it was powered by two inline engines in a fuselage nose, one after another, driving two Contra-rotating propellers. The design had quite unusual look, with long fuselage nose and a crew cab moved rearwards, towards double tailfin. Wings had a fighter-like form and their span was rather short.

The first prototype S-1 was built in 1939, but it was made in order to evaluate an airframe only and was powered by only one engine M-103. It was unarmed and fitted with a fixed skid landing gear. It first flew on January 29, 1940. A maximum speed was 400 km/h.

The second prototype S-2 was powered by two engines and was armed with a single machinegun and bombs. Four 100 kg bombs were carried vertically in a bay between pilot and a rear gunner-navigator, under a common canopy. Its tests started from March 20, 1940. A maximum speed reached was 570 km/h. The plane had good handling, except for take-off and landing, which were difficult due to high wing loading. Its range and speed were also lower, than estimated. As a result, it was decided to improve the plane further. However, the plane was not developed in a favour of next Bolkhovitinov designs, that eventually were not built.

It was first planned to build also an attack plane with 2 Ultra-ShKAS machineguns with extremely high rate of fire, in a rear part of fuselge, firing downwards and manned by a second crew member. Also an interceptor aircraft was proposed, armed with 37 mm recoilless rifle, firing upwards, at an angle and manned by two crewmen.

Operators

;USSR
*Soviet Air Force

pecifications (S-2)

aircraft specifications
plane or copter?=plane
jet or prop?=neither
ref=
crew=two
capacity=
payload main=
payload alt=
length main= 13.20 m
length alt=
span main= 11.40 m
span alt=
height main=
height alt=
area main= 22.9 m²
area alt=
airfoil=
empty weight main= 3,400 kg
empty weight alt=
loaded weight main= 5,150 kg
loaded weight alt=
useful load main=
useful load alt=
max takeoff weight main=
max takeoff weight alt=
more general=
engine (prop)=M-103
type of prop=inline engines
number of props=2
power main=960 hp
power alt=
max speed main=570 km/h
max speed alt=
cruise speed main=520 km/h
cruise speed alt=
never exceed speed main=
never exceed speed alt=
stall speed main=
stall speed alt=
range main=700 km
range alt=
ceiling main=
ceiling alt=
climb rate main=
climb rate alt=
loading main=
loading alt=
power/mass main=
power/mass alt=
armament=
* Guns:
** 2× 12.7 mm UBT machine guns (manned by a rear gunner)
* Bombs:
** Internal 400 kg

External links

* [http://www.airwar.ru/enc/bww2/sparka.html Description (in Russian), photos and drawing at Ugolok Neba]