Show howo lo 10 wan lawt f AIRPLANE I 1 k blo 6 catch KeiG uH haaze Sa aze BASIC FLIGHT instruction LESSON NUMBER ELEVEN robinson right so far but can cai you tell me anything about how it i does docs that how it li Is constructed hank bank it II has an evacuated chamber cl which hii ci expands as the weight of the air ail decreases the higher you get the die light tr er the air that expansion which she th lighter U hier air lias has caused moves the hand indicates the height in feet robinson and what is the basis for or height measurements measurement hank hank sea level of course at al ways the basis for ceasur measuring ig altitude robinson right andl and the adjust able hand must always be set at zero before you start a flight and since the altimeter works because of all air pressure and entirely apart from any operation of the plane it does not nol have to be connected with any part of the plane know anything about what you have to look out tor for to keep the altimeter in perfect condition hank nothing that I 1 I 1 know oj of except to be sure that the vent hole in thi the case coi never gets stopped up robinson about all now well take the thermometer know anything about how it works hank on the general principle of any other oilier thermometer it robinson just about the same and there should always be two of thern them one to indicate the water outlet temperature and another to show the temperature ot of the lubricating oil of course where theres arf anair air cooled engine in the plane one needs only the oil thermometer id better explain just how they work A pressure gauge Is connected with the engine bya by a small metal tube on the end of that tube Is a bulb filled with either gas or liquid under pressure the bulb Is inserted in the oil if its the oil thermometer change ol of temperature causes the gas or liquid to expand or contract and that makes the indicator hand show the temperature thermometers are valuable to a pilot an overheated engine means trouble hank I 1 can set see how it would this Is a mi mighty 9 itty good looking clock on abis board robinson oh this little lob job Is fitted up with the best the chap who owns it knows the value of hoing the best of everything and what he has in this plane aja a clock Is an important part of the equipment hank outside of just knowing nhat time it is robinson that in itself Is important to a flier he be must have accurate time to be able to correctly report p ort his bis position and there are many other uses for clocks in flying there Is the measuring of time required tor for covering given distances or between check points en route checking the rate ot of climb indicator in ascents accents or descents during flight checking rate of turn and checking ground speed and besides all those uses sometimes clocks are provided with a start and stop diaphragm same idea as 83 a stop watch these are known as time of night flight clocks and are operated by pressure from the pilot tube they start running automatically when the plane takes off and stop when the plane lands hank now I 1 have learned something a clock is a lot more to a pilot than just something to tell fell him that his innards arent fooling him when ies time to come down for dinner robinson even a pilot can depend on what his innards tell him for or that now lets get on well take up the speed indicator do you know what a speed indicator does hank indicates the speed at which a plant plane is flying robinson yes but that means not how bow fast the plane Is traveling over the earths surface but how fast it Is passing through the surrounding air hank bank oh I 1 tee see theres an actual difference between air speed and ground speed robinson DeW definitely tely it if the air through which a plane passes were absolutely still then the air speed and ground speed would be the same but that never happens theres always an air current flow tag ing from some direction lank and what is meant by tucking bucking head winds and being helped by mil aci 1 winds robinson it the wind may make a difference ot of twenty or thirty miles ol of speed the airspeed air speed indicator might record a speed ot of miles an hour but tt if the plane is bucking a wind blowing at 30 miles an hour the actual speed relative to the ground Is reduced to only 70 miles it works the other way round too it if the speed indicator registers miles an hour and the alne Is being helped by a tall wind blowing at the rate ot of 20 miles an hour the plane Is actually traveling not miles an hour but miles relative to the ground hank I 1 can see how airspeed air speed indicators work together with an accurate clock in keeping a pilot on his flying schedule robinson they serve that purpose and they serve erye a good many others they w warn rn a pilot ot of an approaching pro aching stalling point or ot of dangerously gerou sly steep dives hank flank just how do airspeed air speed indicatory work bill 1 h I Robinson They are operated by pressure sure or vacuum this one to ll pressure operated you seldom eldom see the pinar tir und kind these then days day just about obsolete now lets see it if I 1 c can make it clear to you just how they work the pressure comes from a pilot or centuri tube fastened to an interplant inter plane strut that how bow this one Is attached sometimes they are fastened to an outrigger from the leading edge edg e of the wing the pressure crest created ed by the planes passing through the air Is transmitted by means of a tube to the indicator mechanism this instrument Is of the tube type which expands a sensitive flexible metal diaphragm which works the indicator hand telling the air speed of the plane in miles its it in miles es in all american built lar land ad planes hank sounds like its iti a pretty complicated piece of mechanism robinson its it not nearly so complicated as a some of the other instruments instrument but one thing you must never directional gyroscope shows any deviation from course OU oil pressure gauge indicates oil circulation s altimeter indicates the distance of the plane above sea level radio com compass ass indicates direction of radio station do dont ever blow your breath into an airspeed air speed indicator to find out if its working all right the pressure at which it operates Is so delicate that if you blow into one of them be almost sure to blow out the diaphragm and ruin the instrument and water should never be allowed to get into the tubing that would cause it to record inaccurately or not at all lank hank and this is u the turn tarn indicator f robinson right know how that works 0 hank flank how would I 1 know I 1 never saw law one before robinson well weil well lust just introduce you right now ill explain what kind of gadget it Is it Is 1 a small gyroscopic instrument which tells the pilot when his plane has deviated from a straight course hank flank and knowing that is il important if you want to land at the she place you started lor for robinson the idea the turn indicator is very important to a pilot flying a compass course it is so sens sensitive etive to even a slow turn that it almost anticipates it it and warns the pilot to straighten out before the shift from the straight course Is indicated on the magnetic compass in flying a compass course the plane naturally Is headed on the true course and the pilot must keep an eye on the turn indicator to be sure he is keeping to the course the slightest movement of the turn indicator hand to the right or left is warning that the pilot is off course and he instantly corrects that by a turn of the rudder without a turn indicator it its almost impossible to fly a straight course hank I 1 I 1 can understand that hut but I 1 dont understand just fust how the turn indicator works no robinson binson remember I 1 told you that it Is a gyroscopic instrument the inherent principle ot of a gyroscope causes tt it to rolt roll over when it Is turned in a plane at right angles to its rotating axis the small gyroscope of the turn indicator rotates at about revolutions per minute this causes the indicator hand band to move when the plane is getting off course the gyroscope operates from a ventura tube on the outside of the fuselage so that it receives receive the air blast from the propeller hank well looks like a good pilot just iest naturally must have a turn indicator robinson all good pilots do these days and another very helpful instrument to the pilot is the inclinometer hank just ahat does that meant mean robinson it means that a plane should be kept on the level and the inclinometer shows when there is the slightest wing drop it also in case the pilot in darkness or storm cannot depend on the horizon to tell him whether the nose of his hig plane Is up or down gives him that very necessary information that Is because the centrifugal force of the tha turn holds the hall ball in the center so long as the plane does not slip or skid if the bank is either too flat or too steep the bubble will indicate it immediately theres a new gyroscopic ro pitch indicator which im surprised this lad has not used instead of the longitudinal inclinometer hank looks to me like a lot ot of these things should be used even in training planes they teem seem to make the job so 10 much easier robinson maybe they would but the pilots turned out be so good hank all ali these instruments are of comparatively recent development in the early days day seven even during world war days there were no instruments on the planes and a better bunch of pilots than those who flew dew for the allied nations nation never climbed into a cockpit that because they had to be natural flier filers they had to have the sixth tense sense for flying and that Is the idea back of giving young people in training as ai little help from instruments instrument as possible youve all got to develop the faculty of depending on your own knowledge of the plane how it behaves and why FU explain what the inclinometer Is I 1 and how it works its it merely a glass glas tube ot of accurate curvature which contains a liquid with an air bubble in it or a steel ball he has both types one on the lateral and one on the longitudinal axis of the plane so he be can tell when the plane is I 1 dropping a wing to right or left and also when the nose is above or falling below the horizon and these inclinometers inclinometer serve a valuable purpose in banking and turning when the plane Is properly banked for a turn the bubble remains in the middle of the tube even though the plane is 13 banked at a very steep angle these gyroscopic pitch indicators indicator serve the pilot at all times exactly as the natural horizon does telling him when the noso nos is up or down and as I 1 just said cald there are many times when conditions prevent the pilot from depending on the natural horizon As A you get further along in flying have a plane with a lot of these instruments st but while serve you and assure greater safety in a hundred did different erent ways which is the reason tor for them find that your best dependence always alway Is on yourself but quite a long lecture to deliver on the why and why not of instruments instrument tor for the beginner in flying hank I 1 see what you mean bill A fellow who learns to depend on himself will ivill make tt a better pilot in the long run than the one who starts out by depending on instruments robinson precisely young fellow but dont understand me to say gy that I 1 undervalue instruments I 1 dont a tremendous help and have contributed no end to safe flying but when you come right down to it they are after all mechanical ch gadgets and in flying probably more than in any other training the human element Is the thing to depend on all the instruments st you could pack into a plane make a pilot they could only help him with the job lank hank you make me glad that rm fin learning to fly almost amot without instruments but just the same im glad I 1 of youre taking the time to explain akem them to me now lets lees see heres the air distance recorder suppose you tell me m how that works robinson gladly naturally its it purpose is to record the air mileage of a plane in flight it has ba two units a 11 transmitter and a recorder the transmitter is I 1 placed to in a strut the same as the tube and is if connected by a tube with the recorder there Is a very small propeller the blades of which are accurately cura tely set and these cause the mechanism to rotate a definite number of times per air milt mile ed note lesson on instruments instrument continued la in next lesson |