886 May 27, 1960 the ENGINEER
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886 May 27, 1960 THE ENGINEER ecor I A shaft-turbine-engined " Bluebird " designed to exceed 400 rn.p.h. is being built for Mr. Donafd Campbe/1 to use in an allempt upon the world land speed record. The specifica- tions and overall design were prepared by Norris Brothers, Ltd., and proved to be within the state of the art for all components except tyres. N September this year Mr. Donald could belong to a motor cycle or to a vehicle chamber installation was virtually mandatory, I Campbell intends to attack the world's with reaction propulsion. It need hardly be so that the steel-tube-frame construction of land speed record at the Bonneville Salt remarked that no wheeled vehicle can the Norris-designed " Bluebird " hydroplane Flats, Utah, U .S.A., with a new " Bluebird," approach the speeds attained by rocket sleds was forsaken for an " egg-box " design in the "C.N.7." The record was set at in various research establishments. which the strength members are panels 394.196 m.p.h. in 1947 by the late John Cobb, The first tentative design used wheels capable of supporting a pressure differential. and the " C.N.7 " was projected by Norris 48in diameter over the tyre, but the Dunlop Further, the large cross-section of the engine Brothers, Ltd., the consulting engineers of Rubber Company, Ltd., which has been rendered unacceptable designs including a whom Mr. Campbell is chairman, to have a and is responsible in all respects for the tyres, differential between front and rear wheels maximum speed of 475 m.p.h. The evolution considered 50in the minimum at which (the desirability of torque division will be of light and powerful gas turbines has centrifugal forces could be accepted and discussed in detail below) and so the engine rendered the generation of sufficient power on preferred 52in as offering prospects of even was modified to have a drive shaft leading a moving vehicle no longer a serious problem, higher speeds. The 52in diameter appealed back from behind the power turbine bearing. and during the design of the car it proved that to the designers because it gave adequate Since this implied that the rear final drive the one component whose capability limited ground clearance with the engine (a Bristol- would have an input at turbine speed, the the performance and dictated alterations to now Bristol-Siddeley- " Proteus" was engine reduction gear at the compressor end the design was the tyre. Weight saving and selected from the first) centre-line in the plane was discarded, although the Allen-Stoekicht even drag reduction are prosecuted solely to of the wheel centres* ; it is interesting to note high-speed gearbox of a " Marine Proteus " lighten the duty of the tyres. that the ground clearance remains positive was fitted for dynamometer testing. A very It should be made clear that the car has with one tyre deflated, and that if the vehicle firm requirement in the specification was that been designed to establish a record which will overturns it will be supported on the tops of full engine torque should not cause more than be recognised by the International Auto- the wheels. The use of a " Proteus " a 5 per cent variation in the ground reactions mobile Federation, whose regulations state dictated other important characteristics of of the wheels, and the use of high-speed that it must have at least four wheels, the design ; since it has, in effect, a ring of air transmission shafts reduced the torsional " not aligned," always in contact with the intakes around the centre section, a plenum stiffness necessary to satisfy this criterion. ground, at least two of the wheels steering The external shape of the c3r was, of and at least two driving. Thus, in principle, • From the references to the many forms of " Proteus " that course, dictated largely by aerodynamic the car holding the I.A.F. record need not have appeared in these pages, it will be recalled that, because of considerations. For safety, it was decided its reverse Aow construction with an axial-centrifugal compressor, hold the absolute land speed record, which it is a relatively short and fat engine. that the pitching moment must be inadequate STE.E.L WHE.E.LS WITH HONEYCOMB MAIN BEAMS FOUR -WAY EXHAUST DUCT DE.TACHABLE RIMS -- --... -.. I OL£O.PNE.UMATIC CONSTANT VELOCITY RE.MOVA8L£ 52 INCH DIA. SPRING COUPLINGS HONEYCOMB PANE.L TYRES The strength members, showing the location of the stabllased sandwach panels. The exhaust ducts pass through the large kadney- shaped holes in the inner aft panels • (Above). Cro s ection of C. .7 • • • ::I: AECIRCULA TING BALL GE.AA80 X SUSPENSION ARMS " PROTEUS" GAS TURBIN£ LIFTING JACKS .CAMAAA AND UGHTS tr1 STE.E.RING NUT I I ;r tr1 HIGH TE.NSIL£ STEEL FRE.E. WHE.E.L DEVICE. GEARBOX OIL TANK AIR BRAKE. ---1 • z WE.LDE.D HUB \ DRIV£R'S INST1WME.NT PANfL I IN E. XT£NDE.D!' ;· POSITrON 0 • BRAKE. 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JACKS AIR BRAKE 0 0 · - - r--, r--, 0 \ ACTUATING LEVER .-. ,.._ __ __ ---- l } l } .rY1 • 8ATTERIES I -=--- . eisJ: \...- ·--' I .. ---r--v-r • r C: l I - . 11 --- 11 U - T 11 - --- Ill \..£1 , -, I ' ' IRAKf SYSTEM AIR 7 1 • ' STORAGE CYLINDERS FIRE. EXTINGUISHER AIR INTAKE 1 Rf.AA DRIVE REAA SPIRAL BEVEL 'HOTOGRAPHIC C02 BOTTLE. ON ENGINE GEARBO X INSTRUMENT PANEL \\ ' • .f -- , -· .I· I -------- '\ \ I . ' . I • • I i i L.l STEERING REDUCTION • • GEAR 80X '\ LAMINATED I I ENGINE. OIL TANK ENGINE. FRONT £NGINE REAR FUEL TANKS GLASS SCRE.E.N • , i i MOUNTINGS MOUNTINGS I . FRONT PRESSURE • • COCKPIT CANOPY I BULKHEAD • -, I .............. -- - -' ...... ' ..... CANOPY BALANCE. --------- .. 1----- ' • MECHANISM -- REAR TO WING E.Y£ • )J:l: - t= --i \ \ \- I • 1! l ll u 'k 1 • I . I 1:z::-=F- ---- ___ L., \lil I •-- • --\.,- _ w, ____ _ I ---- I -- - --\-..JT / 0 ------- ' I "--- . .............. 1 #"\ - -,\ \ r 4 \\: \ \ \ ELECTRIC FUEL REAA PRESSURE. FRONT TOWING FRONT SPIRAL BEVEL FRONT GEARBOX BULKHEAD WISHBONE. SUSPENSION EYE TWO PEDALS GEARBOX OIL TANK • AND OIL PUMPS Plan and elevation of C.N.7 00 00 -....l I • 888 May 27, 1960 T H E EN G I NEE R but in any case more power is available from later marks of engine. The drive from the compressor end of the l.p. turbine line can be either by a simple shaft or by a shaft leading into a sprag (facto!s affecting the choice Will be outlined In the di scussion of the tyres). The two final drive units have, as indicated above, both shafts in one plane and employ spiral bevel gears with a ratio of 14 : 51 (3 ·64). A simple bevel differential is fitted with a locking pin movable only when the vehicle is at rest. The gears are of 3 D.P., 20 deg. pressure angle, 28 deg. 54 min. spiral angle, and 2l face width ; at standstill, loads may reach 4500 lb per inch face width. The duty of these gears is such that the gearboxes use the same enter-based lubricant as the engine, and additivess to improve the high- temperature qualities of the oil are necessary. A tank for lubricant adjoins the sump of each drive casing, and electric pumps circulate the oil independently of engine speed. The final drives are carried on large brackets on two bulkheads with provision for adjustment to align the input shafts with the engine ; the A later stage in the construction of the shell, showing the suspension wishbones, the " steering" links, and torque reactions are taken into these bulk- the outer end of the drag flap ram. The side bays between the wheels are permanently skinned to form heads by pairs of inclined links at top and torsion boxes. bottom. to support an incidence of 1 deg. if the front obtained by using " sandwich " panels with The output from the differential goes to wheels were assumed to leave the ground, and stabilising cores of" Aeroweb " honeycomb. two large tubes with internal splines. Within that there must be only small movement of The two main beams (26ft by 3ft) and these tubes run the inboard Rzeppa type the centre of pressure with yaw. It may not four subsidiary beams (13ft by 3ft), which are constant velocity points of the Hardy Spicer be too early to remark that the final shape is seen in our illustration, use t in honeycomb propeller shafts ; a conspicuous contrast with expected to show a drag coefficient, referred conventional practice is that any sliding to cross-sectional area, of only 0 ·16, but TABLE imposed by the suspension geometry takes nevertheless the drag at design speed will be Campbell Norris Project Seven "Bluebird" place outside the outer member of the 30 per cent of the weight, i.e. lt tons. universal joint and not inside the inner, thus Length overall ... ••• • •• 30ft Tyre considerations led to the body being Breadth overall ••• . .. 8ft greatly reducing the axial loads that can be Height overall ... • • • . .. 4ft 9in evoked by friction on the splines . designed to have no negative (or, of course, Wheel base .