General: Flexible hose is used in dirigible plumbing to be gone-door to the length of parts subsequent to stationary parts in locations subject to vibration or where a colossal amount of adaptableness is needed. It can as well as facilitate as a connector in metal tubing systems.

Synthetics: Synthetic materials most commonly used in the produce of gymnastic hose are: Buns-N, Neoprene, Butyl and Teflon (trademark of DuPont Corp.).
Buns-N is a synthetic rubber complex which has excellent resistance to petroleum products. Do not confuse taking into account Buna-S for Buna-N. Do not use Buna-N for phosphate ester base hydraulic unstructured (Skydrol ).
Neoprene is a synthetic rubber merged which has an acetylene base. Its resistance to petroleum products is not as amenable as Buna-N but has bigger abrasive resistance. Do not use it for phosphate ester base hydraulic shapeless (Skydrol ).
Butyl is a synthetic rubber complex made from petroleum raw materials. It is an excellent material to use with phosphate ester based hydraulic vague (Skydrol ). Do not use it as soon as petroleum products.
Teflon is the DuPont trade state for tetrafluoroethylene resin. It has a broad lithe temperature range (-65 F to -1-450 F). It is compatible when as regards all substance or agent used. It offers small resistance to flow; sticky viscous materials will not adhere to it. It has less volumetric to the fore payment than rubber and the shelf and relief moving picture is virtually limitless.

Rubber Hose: Flexible rubber hose consists of a seamless synthetic rubber inner tube covered in the past layers of cotton braid and wire braid, and an outer amass of rubber-impregnated cotton braid. This type of hose is intended for use in fuel, oil, coolant, and hydraulic systems. The types of hose are normally classified by the amount of pressure they are designed to withstand knocked out ample operational accomplish-ditions.

Low pressure: any pressure under 250 postscripti.
# Fabric braid reinforcement.
Medium pressure: pressures going on to 3,000 supplementi.
# One wire braid reinforcement.
# Smaller sizes carry pressure occurring to 3,000 appendixi.
# Larger sizes carry pressure happening to 1,500 appendixi.

High pressure: all sizes going on to 3,000 add-oni. vigorous pressures
Identification markings consisting of lines, letters, and numbers are printed concerning the hose. (See figure 2.2.) These code markings behave such opinion as hose size, manufacturer, date of fabricate, and pressure and temperature limits. Code markings backing in replacing a hose later one of the same specification or a recommended the stage. Hose acclaimed for use with phosphate ester base hydraulic formless will be marked “Skydrol a use”. In some instances several types of hose may be all right for the thesame use. Therefore, in order to make the exact hose selection, always talk to to the maintenance or parts directory for the particular airplane.


Teflon Hose: Teflon hose is a nimble hose designed to meet the requirements of well along full of zip temperatures and pressures in gift plane systems. It can generally be used in the same melody as rubber hose. Teflon hose is processed and extruded into tube have an effect on to a desired size. It is covered as well as than stainless steel wire, which is braided on severity of the tube for strength and auspices.
Teflon hose is unaffected by any known fuel, petroleum, or synthetic base oils, alcohol, coolants, or solvents commonly used in plane. Although it is terribly resistant to vibration and fatigue, the principle advantage of this hose is its full of zip strength.

Size Designation: The size of athletic hose is certain by its inside diameter. Sizes are in one-sixteenth-inch increments and are identical to corresponding sizes of rigid tubing, when which it can be used.

Fluid lines in airliner are generally often identified by markers made happening of color codes, words, and geometric symbols. These markers identify each stock’s be in, content, and primary hazard, as neatly as the approach of view of formless flow. Figure 2.3 illustrates the color codes and symbols used to apportion the hydraulic lines.
In most instances, vague lines are marked then 1-inch stamp album or decals, as shown in figure 2.4 (A).



On lines 4 inches in diameter (or larger), lines in oily atmosphere, hot lines, and upon some cool lines, steel tags may be used in place of baby book or decals, as shown in figure 2.4 (B). Paint is used upon lines in engine compartments, where there is the possibility of tapes, decals, or tags bodily drawn into the engine induction system.

In supplement to the above-mentioned markings, certain lines may be tallying identified as to specific do something within a system; for example, DRAIN, VENT, PRESSURE, or RETURN.
Lines conveying fuel may be marked FLAM; lines containing toxic materials are marked TOXIC in place of FLAM. Lines containing physically dangerous materials, such as oxygen, nitrogen, or freon, are marked PHDAN.

The blimp and engine manufacturers are held liable for the original installation of identification markers, but the aviation. mechanic is responsible for their replacement

when it becomes necessary.
Generally, tapes and decals are placed on both ends of a line and at least once in each compartment through which the line runs. In addition, identification markers are placed immediately adjacent to each valve, regulator, filter, or other accessory within a line. Where paint or tags are used, location requirements are the same as for tapes and decals.