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Aviation History
1958
1958 - 0586.PDF
602 FLIGHT CROP CONTROL . . . (b) As it can fly at accurate heights and with a from-zero range ofspeed, the control of chemical application is exact. It can fly into corners and pause to reconnoitre before a tricky operation. Withoutdetailed coverage, armies of tiny survivors may be left to emerge from the corners and reinfest the area after the first rain has washed theinsecticide away. (c) Ability to land anywhere makes a working liaison with the groundorganization an easy matter, and supervision by the grower (if needed) is much simplified. (d) In general, downwash from the helicopter rotor has the effect of"massaging" the spray or dust in amongst the leaves, whereas an aero- plane can provide only a surface layer. This is of enormous advantagewhere pests shelter and evade the surface application, as experience has abundantly proved. (e) Finally, being based on the site, the helicopter can take advantageof every favourable opportunity at short notice (this may be set off against its generally slower methods in comparison with the aeroplane). From the pilot's point of view the helicopter generally is moretedious and fatiguing to fly. Aerial spraying, however, and particu- larly when carried out at near-zero heights and where obstaclespresent a constant hazard, reverses this premise completely. A day spent with a helicopter is placid in comparison with fixed-wingoperations, where constant vigilance, near-limit take-offs and the knowledge that engine failure may present drastic results imposesa very considerable strain indeed. Summing up, it would thus appear at first sight that for cropcontrol the helicopter is superior to the aeroplane in almost every respect; but this is far from being the case. It is only when thecrop is sufficiently inaccessible as to render aeroplane coverage inadequate or cause it to be dangerous that the helicopter demon-strates its remarkable efficiency. Because such conditions prevail throughout most of the British Isles, fixed-wing operations areusually unsatisfactory and uneconomical. Elsewhere in the world the aeroplane has become almost indis-pensable in the field of agriculture. At present some 10,000 aircraft are thus occupied, and in every continent. In a number of instanceseven larger aircraft are required than those available; locust control, for instance, demands an aeroplane with considerable range andcapable of carrying sufficient a load to destroy swarms sometimes up to 20 miles in length. Application rates encountered in top-dressing run up tohundreds of pounds of fertilizer being dumped within a matter of seconds, thus calling for aircraft with very large payloads.Imagine for a moment the need arising to treat grain in the vast prairies of Canada. For such a project one would certainly not thinkin terms of a helicopter, or even an aeroplane smaller than a DC-3! The aeroplane will always play the larger role in agriculture, simplybecause it is suited to the larger areas and consequently is in greater numbers. There will always be that other portion of thework, however, that only the helicopter can do properly. Both are certainly here to stay. TWO-AND-SIXPENNY SUPERSOMCS THOUGH the accompanying picture appears to show a wind-tunnel model of a Javelin, its subject is literally a toy aeroplane. The photograph was taken at the aeroballistics range of theCanadian Armament Research and Development Establishment at Valcartier, Quebec, where investigations are made into theaerodynamic behaviour of aircraft as well as of shells and missiles. A member of the R.C.A.F. in England saw a 4in-long model ofa Javelin—price 2s 6d—made by Meccano, Ltd. Finding that it was aerodynamically accurate, and that even its e.g. happened tobe correctly placed, he initiated a train of action which resulted in a number of similar models being sent to Canada, where theR.C.A.F. is evaluating the Javelin. At Valcartier they were used in high-speed-flow investigations, the speed being obtained notby means of a wind runnel but by firing the model from a gun of 3.125in bore—actually a 17-pounder anti-tank gun with the riflingremoved. The undercarriage was filed off and the model inserted in a sabot. (This device, a protective shoe which falls away fromthe projectile on leaving the muzzle of the gun, is commonly used in ballistics research.) The Canadian news-story from which the above details areextracted concludes with the statement that "the tests showed that the model airplane is a good, stable aircraft and it flew well allalong the range at its supersonic speed—the first model ever to have done so. In fact, the report confirms that the model behavedin much the same efficient way as a real airplane expressly designed for supersonic flight." Technically minded readers may like to calculate the Reynoldsnumber; the free-stream is atmospheric air. The toy at Mach 1-25—with shock-pattern and wake. TI EXTRUDED COLD TT is reported by the Battelle Memorial Institute of Columbus,*• Ohio, that a research programme sponsored by the U.S.A.F. Air Materiel Command manufacturing methods branch has led tothe successful cold extrusion of titanium. Starting with slugs of 1.5in diameter (commercially pure), backward cold extrusion pro-duced cups with wall-thicknesses down to 0.22in. In forward- extrusion studies, cup-shaped billets of the same outside diameterand with a wall-thickness of 0.3125in were cold-extruded down to a wall-thickness of 0.15in with a surface finish from 30 to 60micro-inches. The process is claimed to increase the u.t.s. by some 30 per cent. METALS COMPENDIUM AN extensive section of the recently published Meted Industry**• Handbook and Directory 1958 has been devoted to sum- maries of British Standard aircraft material, D.T.D. andAdmiralty specifications; and as a whole the volume provides a comprehensive and accessible source of information for all thoseengaged in or connected with the non-ferrous metal industries. This is the 47th year of publication and a complimentary copyis issued to each subscriber to the weekly journal Metal Industry (annual subscription rate £3 7s 6d; overseas, £3 12s). Othersmay obtain the combined handbook and directory from the publishers, Iliffe and Sons, Ltd., Dorset House, StamfordStreet, London, S.E.I, at 15s net (or by post 16s 6d) FORTHCOMING EVENTS April 28- May 2. Institute of Metals: Golden Jubilee Meeting.May May May May May May May May May May May "Future 7-17. 9. 3. British Interplanetary Society: a.g.m. 4. Tiger Club: Aerobatic Competition, Sywell. 5. R.Ae.S.: Graduates' and Students' Section: Trends in Naval Air Operations/' by Capt. 0. M. Bailey. 7. Kronfeld Club: "Flying in New Zealand," by Keith Wakeman. Mechanical Handling Exhibition, Earls Court, London. Helicopter Association: "Canadian Research in the Field of Helicopter Icing," by J. R. Stallabrass. 9-11. Channel Islands Aero Club: International Air Rally, Jersey Airport. 14. Kronfeld Club: "1958 World Gliding Championships," by Ann Welch. 15. R.Ae.S.: 46th Wilbur Wright Memorial Lecture: "Auto- matic Flight," by G. W. H. Gardner. 16. Institute of Navigation: "Principles of Inertial Naviga- tion Systems " by E. W. Anderson 21. Kronfeid Club: Debate, "The Golden Age of Gliding has now Pasted." May 24-26. Belgian Aero Club: Brussels Exhibition Rally. May 24-26. Fre|us-St. Raphael Aero Club: Provence Wines Rally May 25-26. S.M A.E.: British National Model Championships, RAF. Station Waterbeach. Sept. 1-7. S.B.A.C. Display and Exhibition, Farnborough. R.Ae.S. Branch Fixtures (to May 21):— May 1, Glasgow, "Small Gas Turbines," by P. J. Johnson. May 6, Luton, "Analogue and Digital Computers." May 8, Cambridge, "Air- craft Accidents," by E. L. Ripley. May 12, Halt on, "The Domain of the Helicopter," by Raoul Hafner May 14, Chester, a.g.m. and film show. May 16, Birmingham, a.g.m. May 21, Hat field, a.g.m.
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