THE NAVIGATOR'S JOB

Hawke's Bay Herald-Tribune, Issue 62, 31 March 1937, Page 7

THE NAVIGATOR'S JOB

-Presa Association.l

New Principfes Used 0n Ocean Flights C0MPARIS0N WITH SHIPS

(By Telegtftph-

... x^L AND, Last Night. } Air navigation is one of the newestj arts,- for though navigation • goes • ,back down the centuries to the time of the .cross stave and the astrolabe, this new navigation has been fined and Speeded up to the special needs of aircraft. .It jhas been simplified, or compli^ated, by lits direct and immediate association iwith Tadio^ but all the radio, the direcIfcion finding, and the constant touch Iwith the point left afid the point ahead, have hot taken from the n&vigator his responsibility; that is to see that the 'plane arrives tfue at its destination, though, over a long ocean stage, it may sidle off a hundred miles from the direct line on the advice of the meteorologistradio combination to avoid bad weather or to pick np a tail wind. ! Normally the 'planes carry one navi- j gator who is solely responsible throngh- ] out the journey. The crew, with thej exception of the steward, is more or less: interchangeable, but each has his re-i sponsible job. The chief pilot may be, relieved of his aetual piloting at the, controls, but he earries the weight of! the position over the whole • trip. The : •radio man has his assistant, and each; . oue, spelling from his specialist job, may take sights for the navigator, but the navigator carrios on, not direotly; .relieved,' seeing that the machine gets; there, over each stage, juggling with •five or six systems, cheeldng one against ■the other, for air. navigation dependsnot on any one system, but on a combination. of them .all — dead Teckoning, the compass, observation of drift, celestial ohser.vation, radio bearings, and: that mysterious something which navigators call to their aSsistance, meaningless to the people they get there. Dead reckoning is old, so is the compass, but, observation of drift is as new as. aircraft,. celestial observations are little! used at se.a, and radip bearings, as they are used .on ocean air. routes, are fresh from the aviation brain box. Newly-Developed Equipment. The chart toohl of a flying-boat isi very nrueh like the chart room of ai steamship, not quite so roomy, though i these flying-boats aTe huge, as we think ; of -aircraft, but fitted with a good deal; moTe Cquipment than most steamBhips; carry.- • There are the Usilal chrolio- , 'meters, sextants, a'lmanacs, nautical : tables, rules, and charts, but added to| standard sea equipment are new and; special deviees, the turn and bank indi- ; eator, the gyroscopic compass, sfpeed and! drift indicator, sextants that fix their ' own horizon, new slide rules and slide tables, new air charts, altimeters, air. speed recorders, and the advices which the Tadio officer, cued by the meteoro-' logist, hands in each quarter or halfhour. The passenger can do nothing' about it; he goes where the pilot takes him, and the pilot follows the navigator 's word. It is a nice question who is really boss. • The course is set upon a large aperi,odic compass let into the chart-room table, and. the pilot steers from a directional gyro again set from the chartroom compass aud reset every fifteen minutes or so, for this direetional gyro is not a full gyroscopic compass, but i's a non-north seeking gyro (suction and not draught driven), which holds the jdirection in which it is set without Iprecessing. On the long stages the automatic pilot is put to work, a'nd the , only— very broadly speaking — thing; jthat is done is to reset the direetional! Igyro at ten or fifteen-minute intervals | |or to change altitude; otherwise thej icontrol is fully automatic. Where the Difference Xdes. j Speed through 'the air and speed ofj the air combine to make air navigation ; more difficult than surface navigation J A steamship at 20 knots may, in mid- : , ocean, travel from dusk till dawn on ; ! dead reckoning alone, for the medium' in which it moves is moving slowly and | : ocean currents are almanacked and' ' tabled, but not ,yet are air currents tabulated, and probably never will be. ' The steamship can, and does, xun ■ through the night, without observations, on dead reckoning, but the 'plane that j flies through winds of up to 50, may be j 80 miles an hour, is going to be a long j way off course on dead reckoning alone] over eight. houts or more. j So the air navigator earries on, find- ! ing position by the stars, from radio] and drift. In the daytime glass bulbs; containing aluminium powder are drop-: ped to the sea to give a splash of siiver : for the calculation of drift, and at' night a surface flare is used, but the. night may be bad, with the water, 10,000 or 100 feet below, shut off by cloud or fog and the stars invisible, so there remain radio and compass and the navigator 's sixth sense. Only by using a combination of methods can he navigate, and he must use these methods when he can fit them in: the ebmpass when he cannot see land or sea or sky, radio bearings, and the essence of experience and specialisation. He is busiest when the day or | night is clearest, for at twenty knots the black-out storm may be half a day ahead, but at 150 miles an hour it is a bare hour off, and only by establishing position when the way is elear can the next hour of dirty weather be flown through confidently. Night Navigation. Because it is more complicated, night navigation, of no particular aceount for urface craft except when nearing land, , s more exact than day navigation, beause each body in the heavens gives jne line only. In daylight there is one line of latitudc from the sun, but at night, a muitiplicity of stars gives a multiplicity of crossing lines to give a "fix." Surface craft could jtet alona

farly without celestial observations, but aircraft cannot, and So it is that air navigation has contributed snbstan'tially to surface navigation, not only m this particular, but by the shortening Of methods, by a new almanae which xuns to tens while the old almanae ran to hundreds of pages, and by new deviees and new slides and tables. The navigator of the Sikorsky is Mr H. Canaday, who was a meniber 0f the crew of the first Clipper ship over the; North Pacific air line of Pan American. Airways when he was assistant pilot to • Captain Musick. Mr V. Wright, the engineer, was also engineer on the first :North Pacific through flight, and Mr W. !T. Jarboe, who is radio officer at the: Auckland base, was another of this' team. Mr R. Runnells is the radio officer on the Sikorsky, and the three other members of the crew are Me'ssrs 1 Stickrod, Parker, and Holsenbreck, meehanics.