The basic idea behind an oil hydraulic system is very simple: force that is applied at one point is transmitted to another point using an incompressible fluid. The fluid is almost always an oil of some sort. The force is almost always multiplied in the process. It consists of two pistons fitted into glass cylinders filled with oil. If we apply a downward force to one piston, then the force is transmitted to the second piston through the oil in the pipe. Since oil is incompressible, the efficiency is very good -- almost all of the applied force appears at the second piston. The great thing about hydraulic systems is that the pipe connecting the two cylinders can be any length and shape, allowing it to snake through all sorts of things separating the two pistons.A hydraulic system transmits force from one point to another using an incompressible fluid. The fluid is almost always oil and the force is almost always multiplied in the process. Hydraulic systems are extensively used in machine tools, material devices, transport and other mobile equipment. Detailed application- helicopter oil hydraulic system: a hydraulic oil system for a helicopter is provided to include a single distributing oil tank for selective connection with a plurality of conduits leading respectively to a plurality of helicopter parts requiring hydraulic oil. The supply oil tank is located in, or within easy access of, the pilot cabin. It is now customary in helicopters to supply oil to the various hydraulic points including the flight control systems by use of a hydraulic oil feeder. There are usually three or four hydraulic oil storage containers on board including, for instance, a first stage storage container, a second stage storage container and a utility container. These containers are normally connected to the various hydraulic points in the helicopter with such connections being permanent connections. A warning light is included on the indicator panel for the pilot, so that when there is a need for oil in one of the containers, the pilot will know to land the helicopter for the purpose of obtaining a new hydraulic oil supply. Such a warning signal usually occurs when, for instance, the first and second storage containers are empty and when the pilot can only rely upon the utility storage container. Resupply is accomplished within the present state of the art only by landing the helicopter and temporarily connecting to a portable system for feeding hydraulic oil.
During the process of resupply, the helicopter is usually grounded for approximately one hour, and this process of resupply is generally required every three or four hours of flight time. The design of a new system for accomplishing hydraulic oil replenishment within the framework structurally of the existing system is an endeavor which will contribute immeasurably not only to the convenience requirements but also to the safety requirements of both helicopter manufacturers and pilots.
