Radar dome

Electrical Properties. CeUular polymers have two important electrical appHcations (22). One takes advantage of the combination of inherent toughness and moisture resistance of polymers along with the decreased dielectric constant and dissipation factor of the foamed state to use ceUular polymers as electrical-wire insulation (97). The other combines the low dissipation factor and the rigidity of plastic foams in the constmction of radar domes. Polyurethane foams have been used as high voltage electrical insulation (213). 

The foams, marketed by Rohm as Rohacell, are stable at room temperature to hydrocarbons, ketones, chlorinated solvents and 10% sulphuric acid. They may be used under load at temperature up to 160°C. Uses quoted for these materials include bus engine covers, aircraft landing gear doors, radar domes, domes, ski cores and tennis racket cores. Their potential is in applications demanding a level of heat deformation resistance, solvent resistance and stiffness not exhibited by more well-known cellular polymers such as expanded polystyrene and the polyurethane foams. 

An AWACS is a modified Boeing 707, with a saucer-shaped radar dome on the top, equipped inside with powerful radars and radio equipment that scan the sky for aircraft. A computer takes raw data from the radar dome, processes it, and ultimately displays tactical information on fourteen color consoles arranged in rows of three throughout the rear of the aircraft. AWACS have the capability to track approximately one thousand enemy aircraft at once while directing one hundred friendly ones [159]. 

R D research development R M reliability and maintainability R R repeatability and reproducibility rad That quantity of ionizing radiation that results in the absorption of 100 ergs of energy per gram of irradiated material, radome radar dome RAM radar absorbent material RAM random access memory Rapra Rubber Plastics Research Assoc. 

Safety Considerations. High-power lasers raise a number of safety issues. There are the flammability and the toxicity of dye solutions. Most importantly, the eye hazards of laser radiation require careful shielding of the beam, and interlocks that restrict access to the laser room and to the dome. The laser could also dazzle aircraft pilots if they look directly down the beam. It is therefore necessary to close a shutter in the beam when a plane comes too close, either manually by human spotters, or automatically by use of radar, thermal IR or CCD cameras. Care must also be taken to avoid hitting overhead satellites in the case of pulsed or high power laser systems. 

One of the most recent applications of the. VADS is in the US Navy s Phalanx ship-board antimissile system. Nine hundred-fifty discarding sabot depleted uranium rounds are carried in the feed system, and search and tracking radar are carried in a dome above the mounting. The gun is controlled automatically by the ship s fire-control computer, and a closed-loop spotting system measures the positons of target and projectile simultaneously to direct the stream of fire (at 3000 rds/minute) on to the target thruout the engagement (Ref 3)... 

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