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Aviation History
1953
1953 - 1292.PDF
448 FLIGHT NEW DEVELOPMENTS . . . breakaway from previous practice and with a very neat impeller. This pump, which delivers up to 1,600 gal/hr off a 24-volt system, is avail able in several forms, the usual mounting being on the side of the tank. The Canberra, originally fitted with the B.P.3 pump, now has Type SPE 1003, capable of delivering no less than 1,000 gal/hr,i although it is no larger or heavier—at Hi lb—than its predecessor. Mounted at the bottom of the tank, and with a standard centrifugal impeller, the pump has increased performance stemming chiefly from an up-rating of the drive motor—which, of course, is of SPE design and manufacture. Under development is a fluid-level switch, which consists simply of a bi-metallic strip mounted on the side of the tank. When the mean fuel level falls below the strip, a continuous electric current heats the strip further than was possible when immersed, and the resulting bending actuates a switch to draw fuel from a different tank. Standard production pumps include those for the Mystere 4— 650 gal/hr at 6 lb/sq in, weighing 6.3 lb—and the Gannet, which requires but 350 gal/hr. Although the main features of Sperry's new family of autopilots are completely secret, some details can now be revealed to supplement those given on September 4th. The pilot's neat control-box governs the main units—amplifier unit, altitude control, and hydraulic control— from which hydraulic power is passed to the exceptionally neat servo motors linked to the aircraft control system—one of which was illus trated last week. The associated flight instrument is an electric horizon gyro. Very high rates of climb and descent can be stabilized by the altitude control and turns up to 70 deg bank can be carried out, hands off, at speeds up to 600 knots indicated. In emergency, the pilot can take out the system by operating a safety trip button on his control column although, as we said on September 4th, any signal tending to give a "hard-over" control movement results in the immediate disen gagement of the system. The complete installation, not including the variable weight of cables, oil and other links, weighs 60 lb in the Mk 11 system; Mk 12, with an approach-coupler, is rather heavier. A new development by J. Stone and Co. (Deptford) (whose great range of aircraft rivets was effectively displayed in showcases and by neat production panelling for the Viscount and Varsity) is a flexible coupling, a model of which was hard at work throughout the show. The adjacent ends of the driving and driven shafts each carry a hard rubber tyre, the two tyres being pressed together when the shafts are installed. The friction between the two transmits a useful torque at all speeds without generating excessive heat or causing undue wear. Permissible limits of relative motion between the shafts are, in the size shown: axial, 5/16in; radial, 3/16in; and angular, 4 deg. Another fabricator of acrylic resins and other plastics, the main exhibit by Suntex was a Provost hood, complete with amber screens. An array of welded Perspex tubing, with a wall-thickness up to half-an- inch, showed neat workmanship, and there was also a display of wing tips moulded in clear Perspex. An associated company, Tyneside Safety Glass, displayed an air-sandwich windscreen. The centre of the T.K.S. (Aircraft De-icing) stand was occupied by a section of airliner leading-edge fitted with the company's porous bronze distributor of de-icing fluid, which has every advantage over the type of distributor previously used. A separate leading-edge panel fitting the de-icer area was alongside to show how, by undoing a few screws, an operator might remove the unit in summer, or for short- range low-level flying, with gain in payload. Most significant was the unobtrusive section of porous stainless steel in one corner of the T.K.S. display: development of such material is going on in this country but, where a useful area is wanted, the U.S.A. is the only source at present. Preliminary testing of American 3ft lengths indicates that porous stainless steel is a great improvement over bronze, and is stronger in 0.03in sheet than bronze is in 0.048in. Further, the stainless can be bent to one-eighth inch radius, which should be sufficient for the fastest aerdfoil yet contemplated. In America we know that such material is to be used on the Convair F-102 fighter, the de-icing medium being hot air; but T.K.S. remain faithful to their R.328 and other fluids, emphasizing that the freezing point depression so gained is important. Another telling demonstration was a comparison of the compressive strength of ordinary ice at -10 deg C (uncrushable between the fingers) with the complete lack of cohesion of ice mixed with a small percentage of T.K.S. fluid. The central item on the stand of Thermo-Plastics was a complete Hunter canopy blown in half-inch acrylic resin sheet of Perspex type. Although it is difficult to get the optical quality required, this canopy —a standard production job—was as good as any we have seen; it is also, of course, stressed for supersonic flight at the widely varying conditions of temperature and pressure met by the Hunter. A slightly easier job is the Seahawk hood, also on view, which has rather more metal framing. The Seahawk pilots, by the way, wear the standard Royal Navy hard helmet, for which Thermo-Plastics supply Helmets, Ltd., of Wheathampstead, with nylon-impregnated phenolic resin (of which the unit is made) and also the vizor of tinted Perspex. Many new lines of development were on view at the stand of Triplex safety glass. One exhibit was a specimen heated panel embodying a grid of 0.0008in nichrome wires, spaced parallel eighty to the inch, the heating current being applied across copper busbars at the ends of the wires. To overcome the slight hindrance to vision which the wires cause—particularly the odd blue glint experienced in certain conditions —the company have developed a gold-film heating method, to be marketed as Triplex GF. It is quite new to this country and, with it, rainbow effects or vision interference are completely absent. In fact, Triplex say "this is the answer." The film of gold and an unspecified metal oxide is deposited with a uniform thickness of 0.0000002in (50 Angstrom units)under the first glass lamination, of some 3/16in. Power can be applied across the film at an intensity of between 750 and 1,000 watts per square foot. Although GF is still principally a laboratory development, Triplex believe that with it they have sur passed the American NESA corporation, who pioneered the technology. Supplementing the famous Venner range of lightweight accumulators were a number of magnetic relays having a number of aircraft applica tions. Double-pole, two-way, 25 amp contacts or four-pole, two-way, 10 amp contacts are available, all the relays operating off a 24 v direct-current supply. The units appeared to be exceptionally neat, and they can be supplied in cases of aluminium or moulded plastic. A very attractive dark green plastic on the stand of Wallington Weston proved to be FromoPLAS, a quite remarkable material. Supplied as a chip moulding powder, FromoPLAS is possibly the strongest plastic available anywhere. With a tensile strength approximating to that of cold- rolled aluminium, it is less than half as densj (S.G. = 1.24) and shows a remarkable range of good properties. Examples were shown of sheet after the passage of 0 303in bullets, or the arresting of a 9mm pro jectile and the deflection of a 0.22 pellet, all fired at 90 deg from 25yd; the material was in no case seriously affected, and all that was visible was a small hole or depression, almost completely sealed up by the Soon to feed super sonic power: S.P.E. pump Type 1607, which incorporates several new features. It can pass over 1,600 qaljhr. (Self- Priming Pump and Engineering Co., Ltd.) material's "self-sealing" property. Some properties are: tensile, 10,000 lb/sq in; shear, 18,000 lb/sq in; Izod (half-inch-square notched bar), 14-16 ft-lb; elongation, 15-20 per cent at break. From PLAS can be moulded, machined, welded, and bonded to itself and to metals. Although Western Manufacturing (Reading) are best known as producers of electric equipment, they are now developing a range of pneumatic actuators in order to overcome the temperature limitations inherent in D.C. motors. The Type ARJ.55 Mk 1 actuator shown was capable of operating over the range —55 deg C to +200 deg C; driven by a simple irreversible motor taking air at from 10 to 300 lb/sq in—compressor bleed air, for example—the rotary drive over 180-deg range offered a maximum torque of 100 lb-in, the full move ment taking 15 seconds against a load of 55 lb-in. This performance was substantially independent of supply pressure, the control being effected by solenoid-operated valves and electric limit switches working off a 24 v supply. Total weight was 6 lb 6 oz. Almost every country makes use of the Nimonic alloys developed by Mond Nickel and fabricated by Henry Wiggin. The latest alloys of which details may be given are Nimonic 90—containing a proportion of cobalt and having creep properties such that it may be used between 800 and 870 deg C—and Nimonic 95, the latest alloy in use and a general improvement over "90." The well-known flame-tube material, Nimonic 75 sheet, has now been modified into Nimonic F, the new alloy having a higher iron content. The resistance to oxyda- tion of the new alloy is very good and it is accepted as the equivalent of "75" for flame tubes and other hot parts. Of great consequence is the new Nimoply, a sandwich of heat-conducting copper between two sheets of Nimonic 75. When all the production problems have been solved Nimoply is certain to be of great value in gas turbines. S.B.A.C. OFFICERS, 1953-54 OFFICERS of the Society of British Aircraft Constructors for 1953-54, together with the constitution of the council and the management committee, and chairmen of other commit tees, are announced by the Society as below. Where there has been a change or addition in relation to the 1952-53 appoint ments, the new name appears in italics. Council President: H. Burroughes. Deputy-President: W. T. Gill. Vice- President: J. J. Parkes. Treasurer: Sir Frederick Handley Page, C.B.E. Members: F. Bates; R. Blackburn, O.B.E.; A. F. Burke, O.B.E H T. Chapman, C.B.E.; Capt. E. D. Clarke, M.C.; Sir Roy Dobson C.B.E., J.P.; T. Gammon, O.B.E.; D. F. Mclntyre; J. Martin, O.B.E. Sir George Nelson; H. G. Nelson; J. D. North; W. E. W. Petter, C.B.E. G. C. D. Russell; F. E. N. St. Barbe; Rear Admiral M. S. Slattery, C.B. Sir Reginald Verdon Smith, J.P.; Sir Frank Spencer Spriggs, K.B.E. Sir Ralph Sorley, K.C.B., O.B.E., D.S.C.; W. A. Summers; C. F Uwins, O.B.E.; Sir Norman Watson, Bt.; E. C. Wheeldon; H. M. Woodhams, C.B.E.; Major M. E. A. Wright, A.F.C.; R. P. H. Yapp Group A associate members' representatives: G. W. Lacey, C.B.E. Major E. I. Scott, M.C. Group B associate members' representatives: L. A. Morgan; E. Sayers; S. W. Hughes. Management Committee H. Burroughes, R. Blackburn, A. F. Burke, H. T. Chapman, Capt. E. D. Clarke, Sir Roy Dobson, T. Gammon, W. T. Gill, H. G. Nelson, J. D. North, Sir Frederick Handlev Page, J. J. Parkes, F. E. N. St. Barbe, Sir Reginald Verdon Smith, Sir Frank Spencer Spriggs. Group A representative: G. W. Lacey. Group B representatives: L. A. Morgan, E. Sayers. Committee chairmen: Sales and Export, F. E. N. St. Barbe; Con tracts advisory, A. S. Kennedy; Group A associate menber, G. W. Lacey; Group B associate member, L. A. Morgan; Test Pilots, C. F. Uwins; Technical board and technical executive, R. S. Stafford.
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