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Aviation History
1949
1949 - 0143.PDF
JANUARY 27TH, 1949 FLIGHT wall chart form,' recommended protective treatment for all classes of materials havd been made available tc* the industry. A new work of considerable importance now available ftonY the Society at a cost of £z (the price to cover subsequent amendments) is that concerning a standard method of '' Pro- peller Performance Estimation.1' In the past, discrepancies have existed in the quotation of estimates by various produ- cing companies, caused largely by basing their calculations on different methods and fundamental assumptions. In addition to its value as a standard, this new standard method will result in a great saving in calculation time. It has been esti- mated that 10 to 15 minutes should be sufficient to enable acomparison to be made for a given condition. The average time -for calculations for a series of conditions should be shorter. To quote two more examples as a final indication of the widerange of work upon which the Society is engaged, mention should be made of the present study, in conjunction with theA.R.B., of the airworthiness requirements of helicopters for the granting of certificates of airworthiness, and of the prepara-tion of a standard formula for the estimation of the economics of civil air transport operation—the latter, a most formidabletask. . • .. . . . . F.A.I. Rules for Point-to-Point Records IN the January issue of the Royal Aero Club Gazette are pub-lished details of the rules governing Point-to-Point Record flights. The Federation Aeronautique Internationale recognisesas records for such flights the shortest time taken by any pilot flying between capitals of two countries which are members ofthe F.A.I., or between certain capitals of Dominions, Colonies, Protectorates and Dependencies affiliated to the Royal AeroClub of the United Kingdom, irrespective of the size of the aircraft or the number of crew and passengers. The rules governing these records lay down that the F.A.I,shall approve the course for point-to-point records and that the pilot and crew shall possess current F.A.I. Competitor's AnnualLicences. For an attempt to be considered as a record the speed must be not less than 160 km.h., and any previous recordmust be exceeded by a margin of at least 1 per cent. The distance flown must be equivalent to or greater than theofficial distance (Great Circle route) between the recognized centres of the two capitals or cities in question. Airfields chosenfor start and finish must be within 50 kms. of the centres of the capitals or cities concerned, but the times of the start andfinish are taken as the aircraft, in flight, crosses the starting and finishing lines on the airfields. In the inter-capital class, three separate Point-to-PointRecords are obtainable in each approved course; outward, out-and-return, and inward. It is possible for a contestantattempting an out-and-return record to establish at the same time the outward and inward records. To permit direct visualobservation by official timekeepers, contestants must cross starting and finishing lines at a height of not more than 100metres and this applies also to the maximum height at which the turn must be made when attempting an out-and-returnrecord. Apart from these provisions the attempt may be made at whatever altitude the pilot chooses. It is also laid down thatthe contestant must fly level for at least 1,000 metres before crossing the starting line. The special conditions applying topoint-to-point records allow refuelling in the air and repairs to, or replacement of, parts of engine(s) and airframe. Chang-ing of engine(s) or airframe, however, is prohibited and any time spent on the ground between starting and finishing linescounts as flying time. The official distances between centres or capitals or cities will be provided by the Royal Aero Clubon application. Full details of the rules are also obtainable from the Secretary-General, The Royal Aero Club of the UnitedKingdom, 119, Piccadilly, London, W.i. GHOST-VAMPIRE TIMES TO HEIGHT BESIDES enabling Mr. John Cunningham to capture theworld's altitude record with a climb to 59,446ft, on March 23rd last year, the installation of a D.H. Ghost turbojet in an early Vampire Mk. I airframe has produced some excellent time-to-height figures, which have recently been released. Fly- ing this aircraft, TG 278, on January 31st, 1948, in prepara- tion for the record flight, Mr. Cunningham climbed to 56,500ft in 23 min 50 sec ; 40,000ft was reached in 7 min 45 sec, and 50,000ft in 13^ minutes. These figures were obtained before "278" had been lightened, and its span increased, for the record flight—the take-off weight was, in fact, 8,9971b, 5971b heavier than at the time of the record attempt. The pilot was using 83 per cent of maximum static thrust, and the climb was begun from sea level at best climbing speed without high initial forward speed. Although the original Ghost-Vampire combination was con- ceived solely for experimental purposes, the aircraft's perform- ance at very high altitudes suggests that D.H. interceptor design will benefit considerably from trials of the now-historic "278," stated to be "continuing actively" at Hatfield, toge>ther with '' vigorous development'' of the Vampire air- frame. U.S. LIGHT HELICOPTER HTHE Rotor-Craft XR-11, designed by Mr. Gilbert Magill, isJ- so far the only tandem rotor helicopter to have flown with rigid blades, and it is claimed that inherent stability has beenbuilt into the design without resorting to the use of auxiliary aerofoils or gyroscopic weights. It has been under develop-ment for the U.S.A.F. for some three years and is at present being tested at the Cal-Aero Technical Institute at Glendale,California. The most interesting feature of the XR-11 is the rigid mount-ing of the rotor blades, without hinges or flapping joints, the rotor discs constantly remaining perpendicular to the shaftsand following broadly the principle of the controllable-pitch airscrew. Pitch control rods are enclosed in hollow driveshafts, resulting in a very clean assembly. The blade roots embody levers, which enter the hollow drive shafts via slots,connecting with their respective pitch control rods; the two three-bladed oppositely rotating rotors are mounted in tandemand overlap, the forward rotar turning anti-clockwise and the aft rotor turning clockwise. It is of interest to note that e.g.location is some 40 per cent to the rear of the forward rotor B 7 shaft, which is therefore carrying some 50 per cent greater discloading than the rear shaft. Swashplates for cyclic and collective pitch changes are posi-tioned at the bases of the rotor drive shafts, eliminating a num- ber of components normally used for transferring controlmovements. Mr. Magill claims that the control system is ex- tremely sensitive and the lag in control response is almost im-perceptible. A number of standard automotive parts are incorporated in the structure, reducing initial costs and main-tenance time. The clutch and gears in the rotor assembly are reworked Ford units, a Studebaker free-wheeling unit is em-ployed and all the universal joints are standard car accessories. Welded steel-tube construction is used for the fuselage andthe rotor blades are of laminated birch construction. The engine is a no h.p. Continental C-100 flat four; gross weightis 1,350 pounds; and disc loading is 2.3/lb/sq. ft. Production largely depends upon whether an Air Force contract is forth-coming, but the Company hope to enter the commercial field with a 2-seater, and estimate that the initial price in the caseof a series of 500 machines would be ^2,500 each, followed by a sliding scale to ^1,250. \ ' Rolls so fast, he blacks out one eye at 0 time.''
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