For the first time, both fuel tanks of rocket R-5 were
integral. Experience gained from operating rockets R-1 and
R-2, as well as analysis and experiments showed that evaporation
of liquid oxygen while on a launch pad and during an ascent
phase were not so sizable as it was previously thought and,
with a proper re-supply of the oxygen tank at a launch pad,
heat shield might no longer be needed. Further, such an
approach became routine for a rocket of any design using
liquid oxygen in the capacity of a propellant component.
The rocket R-5 engine was provided with a special extension
nozzle that enabled to increase a flight range up to 1200
km. The pressurized instrumentation compartment was removed.
All control system instruments, except for sensitive elements
(gyroscopic devices and integrators) were housed in a compartment
being a direct continuation of the aft compartment. The
sensitive elements were accommodated far from the engine,
in the inter-tank section on special brackets to avoid vibration
effects. In addition to the autonomous control system, range
radio control, cross range radio correction, and engine
emergency shutdown systems were used for the first time.
The tanks were provided with vortex-free fuel intake devices
to decrease fuel remainders.
characteristics of rocket R-5
Maximum firing range, km
Launch mass, kg
Warhead mass, kg
(liquid oxygen, ethyl alcohol,
hydrogen peroxide, gas), kg
PU ground thrust, kgf
Aerodynamic and heat resistance appeared to be a rather
large problem. The warhead, re-entering atmosphere at a
velocity of above 3000 m/s, was exposed to high temperature
loads. To protect the warhead shell, application specific
coatings based on sublimated (evaporating) high enthalpy
materials have been developed.
Prior to carry out flight tests at the 2 NII-88 affiliate
division, firing bench tests of rocket R-5 were run. The
purpose was to define an actual temperature of propellants
in fuel tanks, verify the control system and engine automatics
functionality, verify the engine firing timeline and record
its actual performance data.
Three cycles of R-5 flight tests were planned of which the
first and the second cycles were experimental and the third
cycle included adjustment and qualification tests.
The first cycle of R-5 flight tests has been carried out
in March - May, 1953. Eight launches have been performed:
two launches - to a range of 270 km, five launches - to
a range of 1200 km, and one launch - to a range of 550 km.
Six of eight rockets reached the destination. The first
successful launch to a maximum range took place on April
While preparing for the second cycle of R-5 tests, a number
of modifications were made to the rocket structure and control
The second cycle of R-5 tests has been run in October-December
1953. A launch range of all 7 rockets was 1185 km. One launch
failed because of a damage in the onboard cabling that triggered
the engine shutdown command and, consequently, resulted
in the rocket undershoot.
The third cycle of R-5 flight tests took place in a period
from August 1954 to February 1955. In total, 19 launches
have been carried out: 5 adjustment launches, 10 qualification
launches and, in addition, 4 adjustment launches were added
because of failures to verify range radio control.
Rocket R-5 introduced a qualitatively new approach to designing
ballistic rockets. With a 37% increase in the R-5 launch
mass its firing range increased two times as compared to
R-2, masses of fore bodies being practically equal. It was
achieved mainly through increasing the engine specific impulse
and sufficiently decreasing (by 25%) the rocket structure
relative mass (without the warhead) that in many aspects
demonstrated technological maturity of the rocket.