Volume 16 No 1 Feb 1965.pdf - Lakes Gliding Club

the first and most basic question is theradar reflectivity of gliders. The Ministryof Aviation must obviously be satisfiedon this point if gliders are to be integratedinto the system, and for thisreason they have placed a contract withthe Marconi Company for research intothis problem. The results of this researchhave not yet come in but a recent pressrelease from Marconi indicated that theyare experimenting with metal foil appliedexternally on some of the glider surfaces.H. C. N. G.HOW TO FALL OUT OF A CLOUDWITHOUT REALLY TRYINGBy RAYMOND JONESSK the average pundit bow he managesto maintain his balance andAhe will probably either give you a blanklook, or muller some incoherent nonsenseabout semi-circular canals in theinner ear. It is generally regarded thatthese organs in the inner ear are mainlyresponsible for keeping the human framethe right wa,y up. This, however, is onlyhalf the story.Few people are aware of the veryimportant part played by the eyes inmaintaining balance, a large proportionof the information received by the brainfrom the inner ear being modified, ifnot completely reversed, by informationreceived from the -eyes. Experience hastaught us that we should be parallel totrees and buildings, and perpendicular tothe ground; so we unconsciously maintainthis position when moving about. Sogreat is the part played by the eyes thatI would even venture to suggest that theyare the body's most important organ ofbalance. Without going into a detailedstudy of the anatomy of the inner ear,let us see why this is so. I feel that alittle understanding of the situation maybe of some help to pilots contemplatingtheir first attempt at cloud flying.Briefly, there are three semi-circularcanals. and these constitute the mainbalancing organ in the inner ear. Eachcanal is perpendicular to the other two,and is itself in either a vertical or ahorizontal plane. One end of each canalopens into a roughly spherical chamberwith a number of sensitive hairs attachedto the inside wall. The whole canal isfilled with fluid. The jdea is that, whenthe head moves in any direction, thefluid tends to get left behind due to itsinertia, the hairs therefore being de-46flected. An electrical impulse is triggeredoff and this carries the relevant ,codedinformation to the brain.All very nice. However, if the motioncontinues, the fluid catches up and thebairs return to their normal position. Anelectrical impulse is :\gain sent to thebrain indicating, this time incorrectly, thatthe motion has stopped. When themotion does in fact stop. the inertia ofthe fluid tends to make it carry on, thehairs being deflected the other way.Once again a message is faithfully transmittedto the brain indicating, again incorrectly.motion in the opposite direction.It can be seen therefore that, statistically.approximately two-thirds of theinformation reeeived by the brain fromthe inner ear is incorrect. We are not,ho~ever, blissfully ignorant of ourmovements for approximately two-thirdsof the time. This is because, wheneverincorrect information from the inner earreaches the brain, it is politely rejectedin favour of correct information receivedfrom the eyes. Over a long period tilebrain has become c-onditioned into acceptingas correct, information from theeyes, whenever it conflicts with that fromother organs of orientation. So strongare the overriding visual impressionstbat we are not normally even aware ofthe false sensations from the inner ear,unless the rate of change of motion isvery vio lent,H we close our eyes, we are left tothe me~cy of our semi-circular canals.These are, however, merciless; just trygoing into a 360· turn with the eyesclosed, and then coming out, Qpemngyour eyes only when you think your