Task 3 – P3
Pneumatics and Hydraulic Systems
Modern aircraft controls and the braking systems use hydraulic pressure as a means of control. This is because the hydraulic system uses fluid, and hydraulic fluid cannot be compressed. Pneumatic systems which use a gas instead of a fluid however can be compressed and this means that the hydraulic system is more effective in it’s function. Because it uses fluid, the effect of the hydraulic system is therefore more precise and can work to create much higher forces – which may be necessary for modern aircraft.
Hydraulic fluids can also be redirected easily – stopped and started mid motion unlike a gas which would need a lot of effort or action to reverse the effect of the pneumatic system.
For a modern aircraft it is also important due to safety checks to be able to determine just where a problem has occurred and if there is a leak in the hydraulic system it is far easier to detect a leak of a fluid than to detect a leak of a gas. This allows for quicker maintenance and less down-time.
Pneumatics also has a bounce-back or a return effect. Once the gas is compressed if released, the mechanism run by the pneumatic system will bounce back to the original state, whereas a hydraulic system will allow the effect to remain that way until moved back.
Using these reasons this is why we use hydraulic systems for modern aircraft for things such as braking and aileron flight control systems. If we used pneumatics for braking, it would be a slower process and not as accurate, it would also require a much stronger force to keep the effect in motion whereas if a hydraulic system is used the effect is much faster. For things such as braking, efficiency in the movement of the action is vital.
For the use of the aileron flight control systems uses hydraulics because hydraulics is faster, and the ailerons cause roll and allow the plane to turn. If we used pneumatic systems for the ailerons the turning effect would