Here is such an interesting, even outwardly mobile complex. Agree, there is something unusual in it!
What is this …
RT-20 (RT-20P) (GRAU index - 8K99, according to the classification of the US Defense Ministry and NATO - SS-X-15 Scrooge (Russian Skryag)) is a Soviet intercontinental ballistic missile as part of the 15P699 ground-based mobile missile system. The first mobile ICBM developed in the USSR. It was not accepted into service. The control system was developed by the Kharkov NPO Elektropribor.
The warheads are monoblock, thermonuclear. The "light" head part had a body made in the form of a set of three truncated cones with spherical blunting. To reduce aerodynamic drag, a conical fairing was installed on the "light" head part, which was dropped during the operation of the second stage engine, when the rocket reached the rarefied layers of the atmosphere. The head part was attached to the upper docking frame of the instrument compartment using three explosive bolts. Three reverse thrust engines were used to separate the warhead from the second stage of the rocket. [4]
The instrument compartment in the case of using the "light" head part has the shape of a truncated cone, the "heavy" head part has a cylindrical shape. The instrument compartment houses the bulk of the missile control system instruments. The 8K99 missile control system is inertial, autonomous with air suspension gyro devices (SU-250 kg weight) and a high-speed digital computer. The communication of the onboard equipment with the launcher is carried out using two blocks of connectors, one of which is located on the side surface of the body of the instrument compartment, the other on the container.
Before the missile leaves the container, the container's connector block is separated using explosive bolts and repulsive springs. After the missile exits the container, the missile connector block is similarly separated. The part of the block remaining on the rocket is closed with a lid. The instrument compartment is bolted to the upper end frame of the fuel compartment.
Promotional video:
The fuel compartment is a container divided by an intermediate bottom into two cavities: the upper one for the oxidizer and the lower one for the fuel. As an oxidizer, nitrogen tetroxide is used as a fuel - asymmetric dimethylhydrazine (UDMH). A 15D12 liquid-propellant rocket engine of the second stage is attached to the lower end frame of the fuel compartment using a rod frame.
The second stage is controlled in pitch and yaw angles by blowing turbogas into the supercritical part of the engine nozzle. For roll control, two pairs of tangentially mounted control nozzles are used, also using turbogas.
The separation of the stages is "hot", i.e. the explosive bolts are triggered after the second stage propulsion system is started. In the shell of the transition compartment there are windows that ensure the escape of gases at the initial stage of the separation process. The collision of the housing of the transitional compartment with the second stage engine during separation was excluded by specially adopted design measures.
The transition compartment is bolted to the first stage solid fuel engine. On the front bottom of the first stage engine, there is a final stage powder rocket engine, which is started after fuel burnout in the first stage engine and ends its work after breaking the connections between the rocket stages. The final stage engine nozzle exits into the main engine cavity.
The tail compartment is attached to the lower end frame of the first stage engine, which protects the engine nozzles and the steering gear from the effects of air flow and gas jets. The executive bodies of the first stage control system are four rotary nozzles of a solid fuel engine. Along the hulls of both rocket stages, the onboard cable network is laid outside and secured with brackets; on the opposite side, along the hull of the second stage, the pipelines of the pneumohydraulic system are laid.
The rocket is attached to the support feet of the container using eight explosive bolts installed on the lower end frame of the first stage engine. The radial movement of the missile and container is impeded by four support rings.
The rocket is launched from a vertically positioned container. The starting container is thermostated. Before the launch, the missile is azimuthally aimed, which consists in aligning the X axis of the gyro-stabilized platform with the firing plane. Rough alignment of the X axis with the firing plane (± 10 °) is performed by turning the launch unit, to exact alignment - by turning the gyro-stabilized platform. Entering the flight task into the control system is remote.
On the command "Start", the operations preceding the launch of the rocket begin: checking the on-board systems, switching the rocket to on-board power supply, etc. Approximately 3 minutes later, after the “Start” command, the extended shaped charge of the TPK cover is detonated, the powder engine for removing the cover is started, and the latter is separated from the container. After separating the container connector block and breaking the bolts of the rocket to the TPK, a powder pressure accumulator located in the container is launched, and when the pressure reaches 6x105N / m2 in the sub-rocket volume, the rocket starts moving.
The shape of the powder charge of the pressure accumulator is selected in such a way that the specified pressure in the sub-rocket volume is maintained constant during the movement of the rocket in the container. At the moment of exit from the TPK, the rocket reaches a speed of 30m / s. At a height of 10-20m above the cutoff of the container, the first stage solid propellant rocket is launched. At the same time, the separation of the support rings and the separation of the rocket connector block is carried out. The first stage engine runs for about 58 seconds. When the pressure in the chamber drops to 5x105N / m2, the final stage powder engine is started, which runs until the fuel is completely burned out. 11 s after starting the engine of the final stage, the second stage engine is started, when it reaches 90% of the rated thrust, the rocket stages are separated.
If a "light" warhead is used for 56 seconds of operation of the second stage engine, the head fairing is reset. When the required combination of parameters of the rocket movement (speed, coordinates, etc.) is achieved, providing a given firing range, the control system issues a command to turn off the engine. At the same time, the head part is separated.
Before the missile leaves the TPK. if necessary, washes can be aborted. The possibility of emergency detonation of a rocket in flight is also provided.
At the first stage of the rocket, four rotary nozzles of a solid propellant engine are used as controls. The rotation of the nozzles is carried out by hydraulic steering gears. A powder pressure accumulator is used to generate gas. The second stage of the rocket is controlled in pitch and yaw angles by means of gas injection into the supercritical part of the liquid-propellant engine nozzle.
The second stage was designed and produced in an ampulized version. The roll angle control of the second stage is carried out by two pairs of tangentially mounted control nozzles. For the operation of the control nozzles and injection, gas is used, which is taken after the turbine of the turbopump unit of the second-stage propulsion system (turbogas). The gas is supplied to the injection and to the control nozzles by gas distributors, which are driven by electric motors.
Each of the first four control channels is a closed-loop automatic control system operating on the principle of eliminating the mismatch between the current value of the controlled parameter and its programmed value. The operation of the fifth and sixth channels is carried out in an open circuit, i.e. when the necessary conditions are met, commands are given to separate the stages, turn off the second stage engine and separate the head section.
The rocket implements the so-called "hot" separation of stages, in which the separation of the first stage occurs after the engine of the second stage is started. At the end of the operation of the first stage engine, the rocket gains an altitude of about 27 km. It is unprofitable to separate the steps at such a low altitude, since, due to the large aerodynamic forces acting on the rocket, significant efforts would be required to separate the steps to a safe distance. In this regard, the stages are separated after the rocket reaches an altitude of ~ 40 km. During the period of ascent to this height, the rocket controllability is provided by an auxiliary engine - a powder rocket engine of the final stage of thrust, which is launched after the fuel burns out in the engine of the first stage.
The separation of the head part is performed at the end of the active section of the trajectory during the aftereffect of the second stage engine thrust. First, three explosive bolts are triggered, with the help of which the head part is attached to the instrument compartment, and then the rocket part of the second stage is decelerated due to the outflow of the pressurizing gas of the oxidizer tank through two antifreezes located on the front bottom of the tank.
The anti-nozzle communicates with the atmosphere through two hatches in the instrument compartment housing. The opening of the nozzles occurs as a result of the operation of elongated detonating charges, driven by electric detonators. The instrument compartment hatch covers are knocked out by plugs flying out of the nozzles. After opening the nozzles, a pyrovalve is triggered, through which the boost gas flows out in a direction perpendicular to the longitudinal axis of the rocket. As a result, the second stage, which also acts as a decoy target, is removed from the trajectory of the warhead.