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Aviation History
1948
1948 - 0148.PDF
128 FLIGHT JANUARY 29TH, 1948 The Way of Achievement The obvious answer to this is to prevent the engine getting too hot, and a great deal of work has been and is being done at Hucknall on this problem. We have alluded to government of thrust on the basis of temperature rather than speed, and it may be appreciated that this is relevant not only to the balance of thrust in multi-jet aircraft, but necessarily has a critical effect on the engine's life. It would not be fair to end this review without some mention of the Ministry of Supply. Certain it is that the design and development qualities are pure Rolls-Royce, but as is the way with so much—too much—of the world, the thing which finally determines the scope of any develop- ment enterprise is money. Although by no means impover- ished, Rolls-Royce could not hope to carry on unaided the enormous scale of their experimental and proving activities. That these, from a national standpoint, must be classed as an essential possession goes without saying, and so it is that virtually the total amount of the company's develop- ment work is covered by appropriate contracts issued by the Ministry of Supply. In conclusion, reference may be made to two develop- ments at Hucknall which are well worthy of mention. The first, although not an item of flight development, is the installation of a 1,000-kVA generator which, driven by a Merlin T-24/2 Lancastrian / York-type power unit, supplies the whole power requirements for the establishment. At present this is used only for two days each week, although, of course, it could be applied for longer if required. The installation is interesting in that it utilizes an adaptation of a c.s. airscrew hub with constant-speed government applied to the throttle to maintain a stable supply despite fluctuating loads. In addition, Nene, combustion chambers were developed during the summer last year to use diesel oil, and are employed to fire the boilers. The other development is that of Hucknall airfield itself. Although the field is run in happy collaboration with the Royal Air Force, Rolls-Royce built the excellent control tower and also installed the runway and approach sodium- lighting system. What is more, the VHF radio system was built by Rolls-Royce, and this, together with the almost unrivalled knowledge of the country which all Hucknall pilots seem to possess, is one of the main reasons why the very high incidence of flying is made possible in a region which is not notable for its fine weather. If asked to what, in my personal opinion, the eminence enjoyed by Rolls-Royce is chiefly due, I think I should at once paraphrase Carlyle and say that it is their transcemi?n\ capacity of taking trouble. It is this quality perhaps more than any other which has made the Rolls-Royce name the epitome of everything that is superb in motoring, and whilst the same exclusive position does not so readily apply in the field of aircraft power, this is not due to any lack on the part of the company so much as to the far greater competition offered them in this field. Nevertheless, installation of a Rolls-Royce power unit in an aircraft is to-day no mere matter of fitting an engine to an airframe. As we have seen, attention is paid to the reliable and efficient functioning of every element which can affect operation of the power unit, and it is only by this patient and exhaustive exploration of every attendant field that the Derby standard is so proudly upheld. HELICOPTER FILMS AT R.Ae.S. '"THREE films made for and issued by the Bell Aircraft-*• Corporation were shown on Tuesday evening, January 20th, to an audience of students and graduates at the RoyalAeronautical Society. The films all dealt with Bell helicopters, but, since theywere obviously designed as a sales medium for exhibition to potential customers, such as farmers, electrical utility com-panies, cattle ranchers, etc., their usefulness to an audience interested in the technics of rotary wing flight was perhapsrelatively slight. This was emphasized by the subsequent questions put to('apt. A. B. H. " Jimmy " Youell, test pilot and demonstrator to Irvin-Bell Helicopter Sales, Ltd., who, in his replies, cer-tainly did well in making up for the filmic deficiencies. Nevertheless, the films, as such, were of a good productionstandard and were of obvious value in their designed field op sales promotion. This is something which might well betaken as a lesson in this country. FOR PHOTO-RECONNAISSANCE "THE splendid service given by various marks of the Mosquito-*- as a long-range, high-altitude photographic reconnaissance machine has not obscured the fact that the efficient executionof modern military reconnaissance flights demands a very specialized aircraft. In America /he Republic XF-12, proto-type of the Rainbow, and the ytighes XF-11 have both been built for the purpose, and are now undergoing prototype trials.Readers are already familiar with the essential characteristics of. the Republic machine, but the following details of theHughes are new. Developed from the Hughes D-2, which had a span of 66ftand was powered by two Pratt and Whitney Double Wasp engines (this machine was struck by lightning and destroyed),the XF-11 is a much larger and more powerful machine, though of the same twin-boom layout. A production order was can-celled on VJ-Day, but Hughes was authorized to proceed with two prototypes and a static test model. It may be remem-bered that he was badly injured in a crash during July, 1946 when the aft bank of the starboard contra-prop of the firstprototype reversed its pitch. As the result of this crash four- blade, jmgle-bank airscrews are now used, and with this instal-lation the second prototype flew during April last year The following is an extract from a flight report by Hughes repro-duced from our contemporary Aviation Week- "It flies like a P.38 and has the best stall characteristicsof any plane I ve flown You get all kinds of warning With power off, flaps and gear down, it is impossible-to stall it on the first attempt. After the wheel is pulled all the way back Ithe nose will come up so far, then drop slightly and pick up speed. It then comes up again and on this second rise youget a good, clean stall. Why it will not stall on the first oscillation I don't know." The second prototype is powered by Wasp Major R-4360-37engines driving Curtiss four-blade airscrews 14ft 8in "in diameter. Each engine has two exhaust-driven turbo-super-chargers, one on each side of the nacelle. Photographic equipment includes, in the extreme nose, aK-17, 18, 19 or 22 camera mounted vertically. Similarly mounted in the nose are two split K-22 cameras, stated to beinterchangeable with the K-17 types. The third camera is of " trimetrogen" design, consisting of three K-17 cameras,one mounted vertically and the other two projecting outward and downward on each side of the nacelle. The cameras canbe operated either from a prone position in the nose or they may be remotely controlled from the camera operator's sgatin the main cockpit. The camera operator, incidental.^ipjb also the co-pilot. Data for the Hughes XF-11 are: span 101ft 5U1; length65ft 5in; weight empty 37,103 lb; normal gross weight 47,500 lb; overload gross weight 58,300 1b; maximum speed420 m.p.h. at 30,000ft; service ceiling 48,800ft; absolute ceiling 48,000ft. An absolute range of 5,000 miles is quoted,but it is not clear if the aircraft is built to carry full photo- graphic equipment for this distance. BIRD VERSUS WINDSCREEN Tj*ROM time to time serious accidents have been caused by-*- penetration of aircraft windscreens by birds, and in some areas abroad, where large birds such as vultures maycongregate in numbers near airfields, the danger is a very real one. The Americans have done considerable research work b.isrdon the firing of bird carcasses from a compressed-air gun at windscreens—an effective, if messy, process. In this coun-try, the K.AE. has carried out experiments with windscreens carried on a rocket-propelled trolley which brings them intoviolent contact with suspended bird-carcasses, while the Bristol Company has developed an elaborate rig by which a"mock-up" bird of canvas and sponge rubber is thrown at the screen by a revolving arm. All these experiments, and particularly the last-named, arediscussed in detail by Mr. E. R. Arbori^ A.F.R.Ae.S., of the Bristol Company, in an article in the February issue of Air-craft Production. A further instalment will describe and illus- tralt- the results of an extended series of tests on the rotor-arm rig'.
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