Show X Ray X-Ray Ray Eyes Radio Ears Banish Ban ish Flaws and Noises From Autos A ufos I BY DY ISRAEL EL KLEI KLEIN KLEIV Science J Editor XI NEA t Ser Service Sen let Feb 32 12 12 DETROIT engineering has been brought down to such finesse In In the tho process of Improving the car that morn more delicate Instruments are arc being used than mans man's own senses The eyes and tho the ears cars of or man manno manno no nn longer are dependable for tor tho discovery of the finer flaws Claws In the thO manufacture of automobiles and automotive parts darts Now X-rays X dr dr- dr dr the slightest defects detects In th ot or parts that no mr me- me mechanical mr instrument let alone th eye eyo could have found Cound Now radio Is 1 being employed employee to take the tho place of ot the ears just jus justas was liS as X-rays X replace the eyes On of the largo large gear gear and bearing manufacturers ot of o tho the United Stat Statuses uses a II radio detector to pick out only those gears and bearings that are almost noiseless or to co eo coordinate coordinate nate gear sets so that their Ibra vibration vibration tion will not harmonize or bt with another part on the same samo car having the same fr Cr In vibration and ane thus cause what we consider noise X Noises are bin bang bing photographed by radio means so that they may muy maybe maybe bo be studied with willi greater precision and leasure This work Is non no going on at nt the General Motors research laboratory here HOW SOUND IS SEE SEEN SEEK At these laboratories to tobe tobe tobe be studied aro are first photographed phi d dby dby by means of ot radio Instruments Instrument II a alight alight light ray machine and ane d film The Tho apparatus consists of three units First a microphone picks up the th noise pulsations In the tho air nil an and changes them into pulsating I etc cli c- c c currents That can b bs be done very vory easily because a II noise is 15 nothing but a series of irregular and complex sound Bound waves aves Having b been en converted into electric pulsations these noise waves are magnified by a vacuum tube amplifier until they become strong trong enough to actuate the dolt deli delicate cats cato element of ot an An Is an Instrument that shows or records the waves of oC a II changing hanging or pulsating cur cur- current current rent LIGHT UGIlT REVEALS nI WAVE tAE While the noise waves naves are sent through the tho amplifier to the os- os os theres there's danger ot of o dis distorting it If It the tha amplifier Isn't un- un under under un under der expert control In the a tiny spot of light reflected from the moving element vibrates back and forth across photographic a 1 film CUm revolvIng revolving revolving ing on II a a drum This spot of lI light ht can cun be seen through a arrangement while It Is belr berg rec rec- rec recorded on the tho film After Arter being developed the film shows a II trace ace representing the form Corm of ot the wave wae as well wel as the Intensity and ane pitch of ot the sound soune picked up by the tho microphone Each of the devices used In this recording recording noise process Is design design- designed designed designed ed especially for this work and lne Is N r 1 fh rw R A s Y sr- sr r 1 k r 4 t w The I Iv more than the ear car nowadays to de tret the sources of oC noises to In autos these noises are arc is b shown by the Il demonstration of oC sounding a fork Cork before a microphone lone shown shorn here c teats en II Is shown 1 below below- th the even wave being that of oC the thc c clear sound of oC the tuning fork tork the irregular crate C that of oC II a noise a finer detector than the ordinary radio equipment known to radio fans NOISE lose IS ELUSIVE E The rhe The apparatus has to bo be ex- ex extremely extremely ex extremely delicate because of the difficulty engineers have In locatIng locatIng locating ing the o ot of a noise noi e Noise Noise- hunting Is difficult because vibrations vibrations vibrations may be telegraphed from Crom one member to another There Is always the danger that tho the wrong part will be accused of ot making the noise It often orten happens too that when the real source Is found the changes necessary to remove It cant can't be made Instead Instead ne or more of ot the parts through which the noise Is being telegraphed telegraph d to the air and the passengers ears cars has to be changed chan so 80 that they will no longer respond to the vibrations of the tho offending part parL In this way many of o the noises that used to bother automobile drivers and their passengers have already been eliminated |