Time for another dull dev blog. This time, the exciting world of Hydraulics which I didn't know much about except what I can gather from various books I have laying around.

Hydraulics are a game component as it effects how long you can maintain control in event of damage to your controls or hydraulic lines and it also powers gun turret control. Controls are not direct in modern aircraft, due to the amount of force required to move a large surface area on an aircraft weighing tons, human muscle has been replaced by a system of wires, pipes, pumps and actuators.

Pressure within this system is vital as it translates a pilots control movement into control surface movement, on a helicopter the cyclic (joystick) operates hydraulic servos that move a large ring under the main rotor called the "swashplate". Wikipedia (swashplate)

I digress.

To simulate damage to this system, we need a basic simulation that isn't too complex as it needs to work for all AI helicopters in our main update loop. If the hydraulic pressure drops then control response has to become "mushy", you should feel this if you're flying a damaged bird. Additionally this should give the AI flying as it's virtual control inputs lag potentially inducing poor looking oscillation. More experience AI crew having faster input response times should be able to handle emergency situations better.

From time of loosing pressure, we're going to give you around 20 minutes to land, your mileage will definitely vary. The ACCumulator stores around 3000psi and is a buffer that maintains the pressure of the primary (PRI) and utility (UTIL) system pressure. These two systems, PRI and UTIL are pressurised from the APU and used to start the engines.

This is reflected in the ENG page during startup. Start the APU, watch the pressures (there's a bleed metric for damage to the system and a fluid level as a percentage). As soon as the primary system reaches around 3000psi (there's a bit of fluctuation added for authenticity) you're good for engine start.

I think this is where the LOCK position of the rotor brake gets it's pressure from.

Almost everything in the Apache is automatic here, operation of this system is handled for you with some exceptions. We have a big Emergency Hydraulics button in the cockpit, pictured below. This allows fluid from the accumulator circuit to flow into the utility circuit. After that, you're on your own.

The things we have to do just to get three numbers up. Oh, and don't get me started on oil pressure ;-)

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