Hydraulic and pneumatic systems k1 k8 k9

What device in a hydraulic system with a constant-delivery pump allows circulation of the fluid when no demands are on the system?

Pressure regulator.

A fully charged hydraulic accumulator provides

a source for additional hydraulic power when heavy

A hydraulic system referred to as a "power pack" system will

have all hydraulic power components located in one unit.

An O-ring intended for use in a hydraulic system using MIL-H-5606 (mineral base) fluid will be marked with

a blue stripe or dot.

A filter incorporating specially treated cellulose paper is identified as a

Micronic filter.

Which of the following is the most commonly used seal to prevent internal and external leakage in both directions of a hydraulic unit?

O-ring.

Which of the following allows fluid to flow unimpeded in one direction but prevents fluid flow in the other direction?

Check valve.

Select the valve used in a hydraulic system that directs pressurized fluid to one end of an actuating cylinder and simultaneously directs return fluid to the reservoir from the other end.

Selector.

One of the distingushing charachteristics of a open-center selectors valve used in a hydraulic system is that

fluid flows through the valve in the OFF position.

What type of packings should be used in hydraulic components to be installed in a system containing Skydrol?

Packing materials made for ester-base fluids.

The component in the hydraulic system that is used to direct the flow of fluid is the

selector valve.

What type of selector valve is one of the most commonly used in hydraulic systems to provide for simultaneous flow of fluid into and out of a connected actuating unit?

Four-port, closed-center valve.

What is the purpose of using backup rings with O-rings in hydraulic systems above 1,500 psi?

Prevent high pressure from extruding the seal between the moving and stationary parts.

The purpose of the pressure regulator in a hydraulic system is to

maintain system operating pressure within a predetermined range and to unload the pump.

Which characteristics apply to aircraft hydraulic systems?

Minimum maintenance requirements, lightweight, and simple to inspect.

What is one advantage of piston-type hydraulic motors over electric motors?

There is no fire hazard if the motor is stalled.

If a hydraulic brake system uses neoprene rubber packing materials, the correct hydraulic fluid to service the system is

mineral-base oil.

The internal resistance of a fluid which tends to prevent it from flowing is called

viscosity.

What is the viscosity of hydraulic fluid?

The internal resistance of a fluid which tends to prevent it from flowing.

Which is a characteristic of petroleum-base hydraulic fluid?

Flammable under normal conditions.

Petroleum-base hydraulic fluid is which color?

Red.

Which of the following is adversely affected by atmospheric humidity if left unprotected?

Skydrol hydraulic fluid.

Which is a characteristic of synthetic-base hydraulic fluid?

High flash point.

Which statement about fluids is correct?

All fluids readily transmit pressure.

Two types of hydraulic fluids currently being used in civil aircraft are

mineral base, and phosphate ester base.

Which of the following lists only desirable properties of a good hydraulic fluid that has chemical stability?

Low viscosity, high flash point, high fire point.

Characteristics of MIL-H-8446 hydraulic fluid are

light purple color, phosphate ester base, fire resistant, butyl rubber seals.

Characteristics of MIL-H-5606 hydraulic fluid are

red color, petroleum base, will burn, synthetic rubber seals.

Characteristics of MIL-H-7644 hydraulic fluid are

blue color, vegetable base, will burn, natural rubber seals.

Excluding lines, which components are required to make up a simple hydraulic system?

Pump, reservoir, selector valve, and actuator.

Heat exchanger cooling units are required in some aircraft hydraulic systems because of

high pressures and high rates of fluid flow.

Some hydraulic systems incorporate a device which is designed to remain open to allow a normal fluid flow in the line, but closed if the fluid flow increases above an established rate. This device is generally referred to as a

hydraulic fuse.

Hydraulic system accumulators serve which of the following functions?

Supplement the system pump when demand is beyond the pump's capacity and store power for limited operation of components if the pump is not operating.

Quick-disconnect couplings in hydraulic systems provide a means of

quickly connecting and disconnecting hydraulic lines without loss of fluid or entrance of air into the system.

A hydraulic pump is a constant-displacement type if it

delivers a uniform rate of flow.

A hydraulic motor converts fluid pressure to

rotary motion.

A flexible sealing element subject to motion is a

packing.

Extrusion of an O-ring seal is prevented in a high-pressure system by the use of a

backup ring on the side of the O-ring away from the pressure.

Where can information be obtained about the compatibility of fire-resistant hydraulic fluid with aircraft materials?

Fluid manufacturer's technical bulletins.

If an aircraft hydraulic system requires mineral-base hydraulic fluid, but phosphate ester-base hydraulic fluid is used, what will be the effect on the system?

System will be contaminated, fluids will not blend, and the seals will fail.

Materials which are Skydrol compatible or resistant include

common aircraft metals, polyurethane, and epoxy paints.

Which seals are used with petroleum-base hydraulic fluids?

Buna-N.

Seals used with a mineral-base hydraulic fluid are identified by which color code?

Blue dot or stripe.

Which seal material is used with phosphate ester-base hydraulic fluid?

Butyl rubber.

One of the main advantages of Skydrol is its

wide operating temperature.

Hydraulic fluid reservoirs are sometimes designed with a standpipe in one of the outlet ports in order to assure emergency supply of fluid. The outlet port with the standpipe in it furnishes fluid to the

normal system power pump.

How many of these seals are used with petroleum-base hydraulic fluids?

Neoprene, Buna-N.

A flexible hydraulic hose identified as MIL-H-8788 will have a strip running the length of the hose. This stripe is

installed without excessive twisting.

If a rigid tube is too short for the flare to reach its seat before tightening, pulling it into place by tightening the nut on the fitting will

may distort the flare.

The installation of a new metal hydraulic line should be made with

enough bends to allow the tube to expand and contract with temperature changes and to absorb vibration.

(Refer to Figure 11.) The AN flared-tube fitting is referred to in which picture?

1.

(Refer to Figure 12.) Which illustration(s) show(s) the correct spiral for teflon backup rings?

1 and 3.