Strana 17
Specifications:
Length: 1680m
Diameter: 650mm
Height: 540mm
Weight: 220 +/- 5kg
Ignition Duration: 9.8 to 17.8 seconds
Maximum Thrust: 1300 to 3000 kp, which
corresponds to a force of between 12,749
and 29,420 N.
SPRD-99 Rocket Assisted Take-Off System (RATO Bottles)
These solid rocket boosters were used
on the MiG-21 to reduce its take-off run.
Two were mounted under the fuselage and
were jettisoned once the aircraft was airborne
and their fuel had been exhausted. These items
were not reusable.
TECHNICS / EQUIPMENT
A detail shot of the same airplane showing the front
and rear attachment points for the right SPRD-99
RATO bottle.
SPRD-99 RATO bottle installed under the left half of the fuselage of a MiG-21bis
of the former GDR Air Force. The method of attaching the rear of the bottle and details
of the nozzle are visible. Photo: Ing. Martin Janousek
Main Components:
Shell, acts as the combustion chamber of the
solid rocket fuel.
Front cover, ensures hermetic sealing of the
casing and also serves to store the igniter
housing with the igniter proper. The inner
surface of the lid is covered with thermal
insulation.
Igniter casing, serves to safely store the igniter
in the front lid.
Rear cover with grate, hermetically seals the
casing and serves to secure the nozzle.
Nozzle with insert, inclined 24°±10´ with
respect to the longitudinal axis of the launch
rocket, serves to create a fixed mode of powder
gas outflow, converts the thermal energy
of the exhaust gases into kinetic energy and
creates the necessary reactive force of the
rocket motor.
Sealing Membrane, ensures hermetic sealing
of the launch rocket, is located in front of the
nozzle insert, is made of aluminum sheet and
is marked 314 – P, which denotes the product
index.
Nozzle cover, protects the inner part of the
SPRD-99 RATO bottle, with the method of attaching the front mount and the shape of the bottle itself visible.
Photo: Ing. Martin Janousek
INFO Eduard
17
May 2025