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Aviation History
1949
1949 - 0070.PDF
FLIGHT JANUARY 13TH, 1949 Nothing To It First General Outline of a New Pilot Aid of Utopian Promise IN the December 18th issue of that famous Americanmagazine, The Saturday Evening Post, there appearsan article written by Captain Hiram W. Sheridan, of American Airlines, regarding a new Sperry instrument which he recently tested on behalf of the Air Line Pilots' Association. We have read this article with extreme inter- est ; and, taking the view that Captain Sheridan has pre- sumably 110 Sperry axe to grind and, as an air line pilot of considerable experience therefore inclines toward the sceptical in appraising any new device, we reason that the eulogistic tenor of his article is of real significance. The new instrument is called the Zero Reader, and the American Sperry Gyroscope Company have been working on it for some considerable time. Although the tone of Capt. Sheridan's article is laudatory there are few techni- cal bones in the meat, and we can therefore do no more than give a very brief resume of what the instrument does ; when factual details are available we shall, of course, give a detailed analysis. In appearance the Zero Reader has a face diameter of about 3 inches, behind which is a black back-plate carry- ing at its centre a miniature silhouette image of an air- craft. Vertical and horizontal cross-wires sweep the face, and the back-plate carries a meridian and equator which intersect at the miniature aircraft. Briefly, the cross-wires are actuated by signals from a gyroscope which detects pitch and roll, so that the instrument can be_ regarded as a type of artificial horizon, and it is quite possible to fly on the instrument in the orthodox manner. However, by feeding in other signals, e.g., from a Gyrosyn compass, radio altimeter, or from a blind approach system such as I.L.S., it is possible to hold any course, any altitude, or any approach path by " zero-ing," that is to say, by keep- ing the cross-wires intersected on the aircraft image. Error Neutralized In broad terms it can be stated that the Zero Reader measures how far you are from where you want to be. It does not indicate what the error is, as a compass might, but simply neutralizes the error at a calculated rate. The pilot does not need, or want, to know what the rate is. This function has the important effect that when, for example, a new course is selected (and from the time of the selection) disparate signals are fed into the instrument from the Gyrosyn compass, and the meridian cross-wire will appropriately be displaced from centre either to the right or left accordingly as the new course is to port or starboard of the extant heading. All the pilot then has to do is to initiate the correction motion in the normal man- ner, and at once the meridian line will zero, and as long as the pilot keeps the line on zero the aircraft will curve on to the right path. By the- same token, this will occur in pitch as well as in yaw. Capt. Sheridan states that the Zero Reader is, in effect, a re-write of automatic approach control with an auto- pilot. In an automatic let-down a detection monitor feeds signals to tiny motors which control the aircraft. The Zero Reader has detection monitoring but no motors; it puts its signals into the cross-wires and the human pilot reads and does his own control. "Zero Readers will make air travel safer," Capt. Sheri- dan emphasizes. "They will make airline schedules as reliable in winter as in summer. In consequence, the air- lines will make money. If that is not revolutionary I will swallow those annual financial reports, red ink and all." It will be possible, although perhaps not desirable, to dispense with the normal blind flying panel instruments in favour of the Zero Reader. This is not to say that the conventional instruments will not be installed: it merely suggests that they may be displaced from their present cardinal positions to less important sites. The mechanisms of the various instruments will be required, of course, as sources of supply for signalling the Zero Reader, but the individual instruments qua indicating devices could be a secondary function. This is a matter of enormous importance in that it would allow canalizing the diverse sources of information which are at present tapped by the pilot, and therefore would make a considerable part of his job very much more simple. Certainly it is early as yet to prophesy the trend of change consequent upon the advent of the Zero Reader, but pilots have for so long wished for some device just such as this that, if it does everything for which it was designed—and Capt. Sheridan, at least, seems completely convinced—then the impact on pilot practice must inevitably be considerable indeed. It is, however, always advisable to look at the black- side of the picture—not necessarily to dwell on it, but at least to appreciate that it is there. Man is a very clever animal and achieves many wonderful things, but Nature remains unchanged, and when she shows her strength even the mightiest of man's achievements are made to tremble. Electrical, radio, radar and electronic devices can and, probably, always will, be "blown," "burnt-out," or "' scuppered " by electrical activity in the atmosphere, and although elaborate precautionary measures can be taken to mitigate the effects, complete immunity is, perhaps, as physically impossible as perpetual motion. That being so, it seems advisable, to say the least, that pilots and navigators should always have a working know- ledge of the old stick-and-string flying and astro-fixing methods, if only to get home safely when all the wonderful modern devices have been made unreliable by Acts of God. NEW YEAH HONOURS (continued from page 23, January 6th) ROYAL RED CROSS (First Class) Acting Matron: R. M. Whyte, A.R.R.C., Princess Mary's R.A.F. Nurs- ing Service. . : •;--> . _ ROYAL BED CROSS (Second Class) Act. Senior Sister: D. M. Schilling, Princess Mary's Royal Air. Force Nurs- ing Service. BRITISH EMPIRE MEDAL (Military) Chief Airman T. J. Bt-pie; Act. Chiel Radio Electrician (Air) (W) W. T. Jinks; Chief Petty Officer (Air A.M. (A) ) F. E. Johnson; Act. Warrant Aircraft Officer S. Jones; Air Artificer J. F. Yeatman. Flight Sgt.s: C. G. Argent; A. J. Coutts; J. E. Frost; W. E. Fuggle; A. E. C. Hellyer; J. A. Marsh; G. C. Mullings; W. W. Phillips; J. Rogers; J. L. Stringfellow; T. W. Tyler; A. A. Wiseman. Sgt.s: D. J. Abercromby ; W. A. Balchin; H. W. Cawte; R. E. Gibson, R.Aux. A.F.; A. C. Hazlitt; R. McDermott; L. S. Pullen; H. J. G. Tailford; J. Thompson. Cpl.s: W. R. Baker, R.A.F.V.R.; P. W. Batty; R. Home; J. S. D. Robb. L. A/C. : A. E. Povvley. Sgts.: E. M. Burns, W.A.A.F.; R. M. Lehane, W.A.A.F.; M. Troy, W.A.A.F.; Cpl.: A. M. Fisher, W.A.A.F. (Civil) Miss W. Annikin, Manageress, N.A.A.F.I. Maintenance Unit, R.A.F., Stafford; Mr. N. Bailey, Fitter, No. 2 M.U., R.A.F., Broadheath; Mr. E. V. Beechey, Principal Foreman, No. 27 M.U., R.A.F., Shawbury; Mr. L. A. Moncrieff, Experimental Officer, T.R.E., M.o.S., Malvern ; Mr. W. Greeu, Service Engineer, Dunlop Rubber Co. B 18
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