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What is a Ram Air Turbine?
Ram Air Turbine (RAT) is a small air turbine that works as a small auxiliary propeller in the aircraft. It connects to an aircraft’s hydraulic pump or electrical generator to use as an emergency power source. So, in case of emergency, Ram Air Turbine comes into action. It generates power or increases engine efficiency from an airstream due to the high speed of an aircraft. With the help of a hydraulic pump, the energy generated from wind converts into electrical power. Thus, accelerating the engine horsepower. This article will learn about A380 Ram Air Turbine working on airbuses to extract sufficient energy in emergency times.
Moreover, modern aircraft use Ram Air Turbine either there is a loss of the hydraulic system or the power generation loses. Generally, RAT is in the fuselage or wing compartment. The A380 Ram Air Turbine also provides vital support such as flight controls, flight-critical instrumentation. In addition, it has navigation and communication equipment. A RAT takes some time for deployment. Meanwhile, the batteries present in aircraft come to work to provide power to essential instrumentation.
What does the Ram Air Turbine do on A380?
A380 Ram Air Turbine is a giant Random Air Turbine with 1.63 meters in diameter. The A380 Ram Air Turbine on this airbus works as part of the electrical system. Moreover, the A380 engine uses an electrical engine-driven generator (EDG) for electric supply in standard cases. There are AC busbars in A380 airbuses that connect to EDG. Furthermore, talking about busbars, different busbars related to various components present in the modern aircraft. You may find AC busbars and DC busbars. The AC busbars power the AC electrical system whenever in need. Likewise, DC busbars power DC electrical systems. The A380 airbus consists of four AC busbars, each supplied with a different EDG. AC1 busbars use EDG 1 for power. Similarly, AC2, AC3, AC4 use EDG2, EDG3, EDG4, respectively.
Thus, when these electrical systems fail, A380 Ram Air Turbine works as a backup. A380 Ram Air Turbine uses the aircraft speed to generate electrical energy from wind. However, the A380 Ram Air Turbine attaches to the emergency generator that supplies all the essential power busbars. Thus, the energy generated by A380 Ram Air Turbine delivers power to all loads of electrical systems. This power is critical for the functioning of the remaining flight system and also for landing.
RAT deployed on A380
Once there is a failure of the flight electrical system, the A380 Ram Air Turbine is deployed automatically. During a routine flight, the RAT is behind closed panels on the fuselage or wing compartment. A380 Ram Air Turbine automatically deploys after it gets a signal when hydraulic pressure decreases. The hydraulic A380 Ram Air Turbine uplocks its hold automatically. Once it uplocks, a spring actuator deploys the turbine and pushes the door to open before it. Manual deployment is also possible in some cases. Thus, the A380 Ram Air Turbine aids safety to the airbus by keeping essential flight functions operational.
Moreover, you may see that in between the AC failure and RAT coming online, Static inverter powers the emergency AC busbars. This static inverter converts DC power into AC power. Once RAT stops due to speed drop, the static inverter again comes into action.
Ram Air Turbine is the heart of an air flight power emergency. It greatly enhances the safety of aircraft. A380 Ram Air Turbine is a small and automatic hydraulic device that governs the turbine to generate power in an emergency. With said that, A380 Ram Air Turbine uses ram pressure from the airstream to generate power to the engines. However, aircraft designers install RAT to overcome the situations in which APU fails. In addition, the greater the flight speed, RAT will generate more power to maintain the essential functions of flight.
Moreover, the A380 airbus electrical system functions on four AC busbars. Therefore, A380 Ram Air Turbine generates energy to provide power supply to emergency AC busbars. Once these AC busbars fail, the hydraulic pressure decreases, sending a signal to RAT. After receiving the signal, the A380 Ram Air Turbine automatically deploys and comes into action. Thus, working as the emergency lifeguard for the aircraft.
How is the design of the RAT system?
The A380 Ram Air Turbine system has an axial-piston, pressure compensating pump. It has hydraulic pump control and an efficient turbine design. The hydraulic system generates forces up to 5000 psi. However, the power depends on the design of the aircraft. You may find three types of pump control in this RAT system. First, a hard-cut off-pump that maintains constant flow pressure. And, above which RAT system destrokes itself suddenly. Second, a soft cut of the pump that carries the same force but in this RAT system gradually destrokes itself once it crosses the limited pressure. Third, power-limiting pumps that have constant torque control and thus avoid the stalling of the RAT system.
Furthermore, the A380 Ram Air Turbine has double the diameter of a regular RAT system. It has a 162 cm turbine diameter with double the rotational speed. The A380 Ram Air Turbine has a two-blade turbine design rotating at a higher rate with excellent efficiency.
How does power generation work on A380?
The A380 airbus uses the combination of AC and DC for its power generation. The primary power generation source is usually AC with an Electrical engine-driven generator. However, the A380 airbus works with four Ac busbars, and each connects to the EDG. Secondary power generates through the DC power source. The A380 is not a DC airbus but uses DC power by converting it into AC. Once the AC power fails, a static inverter comes into action before the RAT system starts. This static inverter generates essential AC power from DC. Moreover, Tertiary power generation is the A380 Ram Air Turbine system that generates essential AC power once the electrical system fails.