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A hydraulic press (often called a hydro press) is a machine that uses a hydraulic system to generate force for compressing, shaping, or crushing materials. It works based on Pascal’s principle, which states that pressure applied to a fluid is distributed equally in all directions.

188,167 次观看 • 1 年前 •via X (Twitter)

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What is the RAT? The RAT is a small wind turbine stowed within the aircraft fuselage and deployed automatically when certain failure conditions are met. Once extended into the airstream, it uses the forward motion of the aircraft to spin and generate power—mechanical, hydraulic, or electrical. Primary Functions of the RAT on the 787-8 1. Hydraulic Backup Power On deployment, the RAT drives a variable displacement inline hydraulic pump. It pressurizes the center hydraulic system, enabling continued operation of critical flight control surfaces such as the ailerons, elevators, and rudder. This is vital in maintaining aircraft controllability if normal hydraulic sources are lost. 2. Supplementary Electrical Power While the RAT is primarily a hydraulic power source on the 787-8, it can also, in some configurations, drive an emergency generator. This generator provides sufficient AC and DC power to support essential avionics, flight displays, and communications systems. Deployment Scenarios: When Does the RAT Automatically Deploy? The RAT on the Boeing 787-8 deploys automatically—without crew input—under the following emergency conditions: 1. Dual Engine Failure If both engines fail, resulting in the loss of engine-driven electrical and hydraulic generation, the RAT deploys to maintain critical flight control power. 2. Complete Electrical Loss to Flight Instruments If there’s a total loss of electrical power to both the captain’s and first officer’s primary flight instruments, the RAT ensures these systems remain powered. 3. Low Pressure in All Three Hydraulic Systems If all three systems—Left, Center, and Right—lose hydraulic pressure, the RAT provides emergency hydraulic power through the center system. 4. EMP Failure + Engine Loss During Takeoff or Landing If all four Electric Motor Pumps (EMPs) fail and an engine fails during takeoff or landing, the RAT deploys to sustain flight control power during these critical phases. Automatic and Autonomous Operation One of the RAT’s key advantages is its fully autonomous activation. Pilots do not need to manually deploy it; the system is designed to react immediately to predefined failure logic, reducing workload and ensuring flight-critical systems remain powered. In Summary The Ram Air Turbine (RAT) on the Boeing 787-8 is not just a backup—it's a lifesaving last resort. It deploys automatically to supply hydraulic and limited electrical power when all other power sources fail. Designed with layered redundancy in mind, it is one of the unsung heroes of modern aircraft systems, ensuring that even in worst-case scenarios, pilots retain control to guide the aircraft—and its passengers—safely to the ground.

Turbine Traveller

293,307 次观看 • 1 年前