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Shuttle
Water-Brake Water Supply Piping - 14001_149

Aviation Boatswains Mate E 3 & 2 - Aviation theories and other practices
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Figure 4-10.—Shuttle. shuttle track. The nose gear launch spreader is attached to the shuttle blade. Water-Brake Cylinders The water brakes stop the forward motion of the shuttle and pistons at the end of the catapult power stroke. The water-brake cylinders (fig. 4-11 ) are installed at the forward end of the launching engine cylinders. The after end of each water-brake cylinder is supported and aligned by the most forward section of each launching engine cylinder, which fits closely around the end of the water-brake cylinder. The forward end of each cylinder is anchored in place by an upper bracket and lower support saddle and chock. The open end of each cylinder holds four rings. They are the choke ring, the annulus ring, the jet ring, and the striker ring. The choke ring is the innermost ring and is threaded into the cylinder to form the water-brake cylinder mouth. The annulus ring has angled holes machined in it to direct pressurized water into the cylinder and forms a vortex (whirlpool) at the open end of the cylinder. The jet ring is bolted to the end of the cylinder and holds the annulus ring in place. The striker ring, the outermost of the four rings, prevents damage to the other three rings and the end of the cylinder when the piston assemblies are maneuvered or advanced into the water brakes. WARNING To prevent damage to the water brakes and piston assembly components, a water-brake pump must be running any time the shuttle and piston assemblies are not fully bottomed in the water brakes. A vane is keyed to the end plug (see fig. 4-11). Its purpose is to breakup the vortex caused by the annulus ring and to create a solid head of water in the cylinder, which is maintained by the continued vortex action at the mouth of the cylinder. Braking action occurs at the end of the power run when the tapered spear on the piston assembly enters the water brake. Water in the brake is displaced by the spear and forced out the after end of the cylinder between the choke ring and the spear. (See fig. 4-2.) Since the spear is tapered, the space between the choke ring and the spear is gradually decreased as the spear moves into the brake cylinder. This arrangement provides a controlled deceleration and energy absorp- tion, which stops the piston assembly within a distance of about 5 feet without damage to the ship’s structure. 4-10







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