Riding The Film (1937)

so so strange as it may seem ice skaters do not skate on ice even the smoothest ice isn't slippery enough for that ice must be lubricated before anything will slide on it the skates really glide over a thin film of water under the skate here's what really happens the blade of the skate cuts a groove and the pressure melts enough ice to cover the groove with water the thin film of water between the skate and the ice acts as a lubricant on which the blade can slide easily a lubricant is something that makes things slippery water is sometimes used for lubrication especially where it can be supplied in large quantities it takes a lot of water to keep this sea going roller coaster from sticking to the chute in some boats a steady flow of water from the outside lubricates the shaft which carries power from the engine to the propeller however water has disadvantages as a lubricant because it won't stay where it is needed it pulls apart too easily and it won't keep its film between moving surfaces when the surfaces are squeezed together with enough pressure the water is squeezed out but there are better lubricants than water when a sticking bureau drawer is stubborn and bulky we can make it slippery with a little soap so that it will work easily for the launching of a liner tons of tallow or hard grease are used to make a smooth slippery path a simple experiment shows the effect of a lubricant we use a block of metal polished to an even finish and a metal incline as smooth as glass without lubrication the block will not slip the two metal surfaces are in actual contact however if we lubricate the same surfaces keep them apart with oil the block will slide of its own weight here magnified thousands of times with the help of micro photography we can see what happens when a metal surface glides over another surface of metal riding on a film of oil oil is a good lubricant because under high or low temperatures it keeps an unbroken film to hold sliding surfaces apart and it won't evaporate oil is liquid enough to get into small openings between closely fitting parts oil is thick enough to form a cushion that stays where it is needed and it is elastic enough to make a film under pressure a small flywheel bearing shows why it is necessary to use a good lubricant we first remove all the grease or oil when we spin the wheel the metal surfaces rub against each other without oil they grow hot the soft bearing metal is melted friction binds the moving parts together and soon the flywheel will stop without the protection of oil both surfaces are ruined there are three general ways of circulating a supply of lubricating oil to the parts of a machine we can arrange a bath of oil so that moving parts can splash into it for lubrication we can provide a supply of oil on a higher level so that it will trickle down through a system of tubing onto the moving parts the force of gravity furnishes the power to carry a steady flow of lubricant where it is needed if we want an extra amount of lubrication we can force a stream under pressure directly onto the sliding surfaces by controlling the pressure we can control the lubrication for different speeds there are many moving parts and many types of moving surfaces in the automobile engine consequently the engines in our cars today use all three methods of lubrication to provide for the wide range of speeds and loads the heart of the lubrication system is the oil pump in the oil pump the two revolving gears create a suction as the teeth move apart this suction draws oil from the storage reservoir or oil pan the gear teeth carry the oil around as they revolve and then as they mesh together force it to the engine parts each gear tooth sends a strong spurt of oil and at normal engine speeds the result is a steady smooth flow in the modern engine the main bearings carry the load of the crankshaft as it whirls at hundreds of revolutions each minute and plenty of lubrication is needed to get this lubrication a constant stream of oil is pumped under pressure directly into the main bearings the camshaft has the job of opening and closing the valves and needs an elastic cushion to protect it from friction the oil flows through tubes to the bearings which carry the camshaft and more oil flows out through a nozzle onto the timing gears which drive the camshaft to keep the valves in smooth operation oil is pumped up into the valve mechanism a special method is used to lubricate the connecting rods a high pressure stream of oil is forced through nozzles in the base of the engine and each jet of oil is accurately aimed to strike a scoop or dipper on the bottom of a connecting rod the oil is forced up into the connecting rod bearing by the scoop-like action of the dipper as it strikes the jet in scooping up water a locomotive uses the same principle a special motion picture camera equipped with what is called a stroboscope lets us see the action of the dipper on a crankshaft that is actually revolving at a speed of 3600 times every minute there is a hole in the bottom of the connecting rod through which the oil passes from the dipper into the bearing at high engine speeds the oil enters the dipper at the rate of 120 miles an hour the barrel shape of the dipper picks up less oil at low speeds then at high speeds and as the connecting rod splashes into the trough it throws a spray of oil over the cylinder walls this spray of oil forms a smooth film to lubricate the speeding piston as it slides up and down in the cylinder a special ring on the piston controls the amount of this film the excess oil is scraped off and carried through holes in the side of the piston to furnish the main lubrication for the piston pin a steady stream of oil flows through the engine bathing the crankshaft the camshaft valves and pistons and connecting rods covering all the moving parts with a protecting film the modern engine uses the same oil over and over again four times a minute at normal speed in order to do this it must be cleaned and cooled each time the oil passes through the engine it is filtered so that dirt and impurities can be kept from the polished surfaces the oil is cooled in the bottom of the engine and allowed to rest in the oil pan efficient crankcase ventilation removes hot corrosive gases so they cannot contaminate the pure oil a tremendous stream of cooling cushioning lubricant is pumped through the engine by connecting a hose to the pump and arranging a return pipe we can see the amount of oil that flows from the pump each minute that the engine is in operation enough to fill a bathtub in three minutes closely fitting highly polished parts moving at high speeds year in and year out demand an adequate supply of good clean oil to protect them from friction and wear to give power economy smooth silent operation and long life with every part riding a film of oil

Channel: US Auto Industry

Views: 921,102

Keywords: Airbus, super, prop, Film, history, (1937), luftfahrt, airline, aviation, Boeing, airplane, The, bowl, Riding, jet

Id: CCtJlgtZnBY

Length: 10min 40sec (640 seconds)

Published: Sun Sep 09 2012