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Aviation History
1950
1950 - 1839.PDF
370 FLIC HI, 5 t-,50 SHORT FLIGHT-TEST DEVELOPMENT the wing centre-section were consequently modi- fied at the design stage to incorporate the requisite cooling duct entries. However, fol- lowing early flight reports of low-speed insta- bility, difficulty in control during landing, poor climb performance, and draught down the pilot's neck, a systematic programme of entry lip development by flight test was initiated. Local ragged airflow characteristics had been verified by wool-tufting the wings. Various lip shapes were tried in turn (constructed of wood for convenience) and the optimum shape eventu- ally determined. The improvements achieved by this means were quite remarkable and not confined purely to handling. The low-speed instability was eliminated, elevator control im- proved, and stalling speed reduced from 74 knots to 68 knots, with a corresponding im- provement in deck-landing attitude. In addi- tion, the rate of climb was increased from 2,000 ft/min to 2,800ft /min, the maximum speed in- creased by 20 knots, engine coolant tempera- tures dropped by 10 deg C and, perhaps most important of all, pilots no longer complained of stiff necks. It is noteworthy that these improvements were all asso- ciated with improved airflow, both external and internal through the radiators. It is considered that the results achieved constitute a glowing testimonial to the merits of aerodynamic refinement and, to a lesser degree, to the use of wool tufts for flow investigation. The foregoing paragraphs illustrate some recent examples of the considerable benefits to be accrued from what might be termed "quality investigation" during prototype flight trials. The value of wool tufts in locating the region in Showing fications the Sturgeon centre-section radiators which were subject to modi-mentioned by Mr. Marshall. which the trouble lies is also emphasized. It is evident that a little time and money spent at this relatively later period of a prototype aircraft's development may pay handsome dividends and ensure that the subsequent production air- craft enter service as really efficient, operational machines. As in the case of the Sturgeon radiator lips and the Sealand cooling modifications, the refinement process may be some- what of the " hit or miss " variety, and, as a consequence, sometimes rather prolonged and tedious. Nevertheless, this appears justified when a really worthwhile improvement in aircraft characteristics finally results. (Having noted the foregoing results, the reader will agree. Ed.) STANDARDIZED POWER-CONDITIONS FOLLOWING the I.C.A.O. policy of international stan-dardization, the ratings of all British power-units are now quoted—by the S.B.A.C, A.R.B. apd Ministry of Supply- according to a standard form of nomenclature for the main operating conditions. Some terms, supplementary to the I.C.A.O.-approved titles, have been introduced by the Ministry of Supply to cover military as well as civil operating condi- tions. The new nomenclature is set out in the following tables: — TURBOJET AND TURBOPROP OPERATING CONDITIONS PISTON-ENGINE OPERATING Power Max take-off Operational necessity Max 'ntermediate ... Max continuous Max weak mixture ... Max overspeed Time Limit 5 min 5 min 60 min Unrestricted Unrestricted 20 sec Military or Civil M and C M M Mand C M and C M and C CONDITIONS ! Remarks — May in some cases be in- creased to 10 or IS minif required. Often same power as max continuous. Minimum r.p.m. sometimes specified for this condition. Usually 105 per cent of max take-off r.p.m. butmay be higher. Power Max Take-off Operational necessity Max take-off and operational necessity Max intermediate ... Max continuous Max overspeed Approach idling Ground idling Time Limit 5 min 5 min lOor IS min 30 min Unrestricted 20 sec Unrestrcted Unrestricted Military or Civil Mand C M M M M and C M and C Mand C Mand C Remarks _ May be increased to 10 min in some cases. Frequently the same as max continuous. Usually 103 per cent of max take-off r.p.m. For use on landing approach. To enable max power to. be reached within 5 sec. For use with no forward speed. A third set of operating conditions has also been laid down —for application to civil piston-engines rated before November i8th, 1946, and not subsequently approved to current B.C.A.K. (I.C.A.O.) standards, e.g., Merlin 500 Series. There are five power-conditions: emergency max (15 min) ; max climbing (60 min) ; international rated (60 min) ; emergency cruising and max cruising (both unrestricted). OBITUARY ALL those in the industry who knew him will be grieved tolearn of the death of Mr. W. H. ("Bill") Mace, who in 1921 joined Hawker Aircraft, Ltd. (at that time H. G. Hawker Engineering Co., Ltd.), as works inspector. A year or so later he became works manager, which position he held until he left the firm 14 years later to go to British Marine Aircraft of Southampton as a director. During the war he was with M.A.P. For several years latterly he had been suffering from a severe illness, and it was this that led to his death—on September 23rd, at Downderry, Cornwall, where he had been living for the last iew years. Flight also regrets to record the passing, which occurred recently in a Belfast hospital, of Mr. E. S. Roper, chief A.I.D. representative with Short Brothers and Harland. Ltd. He was 56 years old. Before joining Shorts in 1946 Eric .Roper had travelled extensively in America as an A.I.D. representative appointed to U.S. factories manufacturing military aircraft and components for Britain. Having served the Directorate since 1924, he had spent tours of duty in most of the leading aircraft factories of the United Kingdom. VAMPIRES IN GREECE Accompanied by three Valettas, Vampires from a squadron iar*v the Canal Zone recently visited Greece. They flew to Athens,-; where they were greeted by the Chief of Staff of the Royal": Hellenic Air Force, by way of El Adem, Cyrenaica. Citizens of, Athens watched formation aerobatics and a formal demonstra*i: tion was given before King Paul. Before leaving, the squadron"" was presented with a plaque, and handed over in return a replica of their crest.
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