Glass fiber reinforced plastic and honeycomb are used in the construction of radomes, wing tips, stabilizer tips, antenna covers, fairings, access covers, etc. It has excellent dielectric characteristics, making it ideal for use in radomes. Its high strength/weight ratio, resistance to mildew and rot, and ease of fabrication make it equally suited for other parts of the aircraft. The manufacture of reinforced plastic laminates involves the usc of liquid resins reinforced with a filler material. The resin, when properly treated with certain agents known as catalysts, or hardeners, changes to an infusible solid.

The reinforcement materials are impregnated with the resin while the latter is still in the liquid (uncured) state. Layers or plies of cloth are stacked up and heated under pressure in a mold to produce the finished, cured shape. Another technique, culled "filament winding," consists of winding a continuous glass filament or tape, impregnated with uncured resin, over a rotating male form. Cure is accomplished in a manner similar to the woven cloth reinforced laminates.

Glass fiber reinforced honeycomb consists of a relatively thick, central layer called the "core" and two outer laminates called "facings." (See figure 1-22.)

The core material commonly used in radome construction consists of a honeycomb structure made of glass cloth impregnated either with a polyester or epoxy or a combination of nylon and phenolic resin. The material is normally fabricated in blocks that are later cut on a band saw to slices of the exact thickness desired, or it may be originally fabricated to the proper thickness.

The facings are made up of several layers of glass cloth, impregnated and bonded together with resin. Each layer of cloth is placed in position and impregnated with resin before another layer is added. Thicker cloths are normally used for the body of the facings, with one or more layers of liner weave cloth on the surface.

The resins are thick, syrupy liquids of the so-called contact-pressure type (requiring little or no pressure during cure), sometimes referred to as contact resins.

They are usually thermosetting polyester or epoxy resins. Cure can be affected by adding a catalyst and heating, or they can be cured at different temperatures by adjusting the amount and type of catalysts. Inspection and repair procedures for reinforced plastic are covered in chapter 14 of this TRAMAN.