Classic Military Vehicle – September 2019

The Osa SAM system mounted on its new
BAZ designed and built 6x6 chassis was in of
itself a major change from earlier air defence
missile systems, in that the acquisition and
targeting radars were mounted directly on the
launch vehicle, greatly increasing autonomy of
operation. The Osa short-range SAM system
had an altitude ceiling of 5km and a range of
9km, later extended to 10km, providing close
support defence for armoured units against
aircraft flying at a speed of under 500m/s,
namely attack helicopters and slow-moving
ground attack fighters. Subsequent upgrades
provided a slightly improved range of 10km
but reduced the minimum engagement
altitude to 250m and also reduced the reaction
time. The vehicle was provided with a 40hp
gas turbine auxiliary power unit for operating
the vehicle systems when the main engine
was shut down.
With the trials successfully completed, the

new BAZ 6x6 amphibious vehicle was accepted
for series production, albeit in modified form
with a larger full width cab with vastly improved
internal space and visibility. Series production
of the chassis began in 1972 as the BAZ-
5937 (SPU launch vehicle), BAZ-5938 (9V210
technical support vehicle) and BAZ-5939 (TZM
trans-loader vehicle).
The 9K33 Osa missile system, with its
9M33 missiles was at the time still under
development, and the Osa missile system and
its dedicated BAZ chassis were to be one of

the most dynamic of Soviet weapons systems,

undergoing a series of upgrades, with several

changes of designation for both the 9K33 SAM

system and the vehicle chassis.

The SPU launch vehicle for the first series

production Osa SAM system was designated

9A33B, with later modifications designated

9A33BM2 and 9A33BM3. The BAZ built chassis

were delivered to the city of Izhevsk, best

known for producing Mikhail Kalashnikov’s

Model-1947 (AK-47) and subsequent designs.

Final assembly of the 9A33B launch vehicles

for the 9K33 Osa SAM system was undertaken

at the Izhevsk Electromechanical Plant - today

within the structure of the ‘Almaz-Antei’ rocket

design and production concern. The BAZ-5937

series was powered by a UTD-20 V-6 diesel

engine developing 300hp (the same engine

as used in the BMP infantry combat vehicle),

linked to a five-speed gearbox and providing

the vehicle with a 60km/h road speed. The

all-terrain vehicle was also fully amphibious by

means of a hydro-jet propulsion system, and

could swim at 8km/h.

The first pre-series 9A33 launcher vehicle

chassis used with the original 9K33 Osa SAM

system had a distinctive blunt nose. By the

time the Osa system had its public debut on

Red Square in November 1977, the 9A33B

chassis had been modified significantly, with

the most obvious change being a modified hull

front, which primarily improved the vehicle’s

amphibious characteristics. Both vehicle

This 9A33BM3 vehicle is returning from a Red

Square parade on November 7, 1986.

MIKHAIL BARYATINSKY

The early production model Osa SAM system

9A33B SPU vehicle at the Central Armed Forces

Museum, Moscow. Note the distinctly flat nose

section, which was modified on later vehicles

The Obiekt-685 was a potential replacement for

the original BMP series. Armed with a 100mm

2A48 gun.

Another early production 9A33B SPU vehicle

for the original 9K33 Osa SAM system, at the

Artillery, Engineer and Communications Museum,

St Petersburg

The original production version of the 9K33 Osa SAM system had its public debut
on Red Square in November 1975, by which time its replacement had already
undergone field evaluation trials

The 9T217 TZM vehicle mounted a small hydraulic crane for reloading 9M33 series rockets onto the 9A33 series
SPU vehicles, with the cargo area covered by a frame and tarpaulin when not required

‘The 9K33 Osa

system was

subsequently

modernised several

times during its

relatively short

service life’