318 AIRCRAF T ENGINEERING December , 1930 A Selection of the More Important Aircraft and Engine Specifications Published Recently 334,021 . Road vehicles; aircraft. small an inductance as possible, so that the enable the method of adding and subtracting Martin, J., Martin's Aircraft Works, Higher loop and antenna effects are in phase. A th e effects of the loop and non-directional Denham, Buckinghamshire. July 16, 1929, separate plain aerial may be used (Fig. 3, not aerial, to be used. In this case the potentio No. 21821. [Classes 4, 79 (iv), 108 (i), and shown), in which case a fixed centre tapping meter winding extends over a semi-circle, the 108 (ii).] of the potentiometer is earthed and the sliding ends being connected to two insulated segments In frame structures for vehicles and aircraft contac t is connected to this aerial. The loop completing the circle and so connected as to a sheet-metal member having screwed bosses ma y be inductively coupled to the non-direc produce the change-over required. Two mov tional aerial circuit (Fig. 5, not shown), an able contacts, connected to earth and the thereon is shaped to fit within or on one of the expedient which enables the angular calibration non-directive aerial, and arranged to revolve in frame members to receive the fastening bolts of the potentiometer to be varied by varying opposite directions, may be provided, either to or studs. A metal member 5 having sides 6, said coupling. Alternatively the non-direc enable the wire to be shortened and the induct 6 is provided with bosses 8 into which bolts or studs 4 are screwed to secure the box girder 2 tional aerial circuit may be coupled to the loop ance reduced, or t o enable a non-directive aerial to girders or sockets 1. The member is slid circuit (Fig. 6, not shown). In a push-pull of less effective height to be used. The within the girder 2 and is shaped to correspond. arrangement (Figs. 7 and 8, not shown) there potentiometer may be replaced by a variometer Each member may be provided with the requi are two loops with the potentiometer between having one winding connected across a fixed them in the common grid circuits of two resistance in series with the plain aerial, the site number of screwed bosses and it may have amplifying valves, or coupled thereto, and a other being connected to the loop through the a curved or oval shape as shown in Fig. 5, the non-directive aerial connected to the variable two coils in the loop circuit. member 5 being split at 9 to provide a springy contact of the potentiometer, a common tuned member while the bosses 8 may have projections [In connection with this paten t readers are referred to Mr. C. B. Carr' s article o n pages 305-7 and the Air Ministry General Notices 8 to spring into the bolt holes of the girder 2". anode circuit being coupled to the succeeding t o Airmen on page 314—Editor] Instead of bosses 8 nuts may be positioned in valves. The potentiometer 4 comprises a any suitable way in the members 5. Specifi cylindrical block 40, Fig. 10, of insulating cation 280,084 is referred to. material mounted in a flanged metal cover 41. Moderate Supercharger " Jupiters " A spindle 42 and worm wheel 43, adapte d t o be The four-engined Handley Page 40-seater land- driven by a worm engaged by a flexible shaft planes and the new four-engined Short boats extending through an extension 45, Fig. 12, of being built for Imperial Airways, are to be equipped th e casing, carries a pointer 47 moving over a with Bristol Jupiter engines of a new type. These scale consisting of two semi-circular portions engines are designed to bridge the gap that has gradually been widening between the normally- of red and green transparent material, clamped aspirated engine and the highly supercharged type between glass plates 48, and calibrated in developing its maximum power at high altitudes. degrees to "Port " and "Starboard" respec The new " X.F.A.M." and " X.F.B.M. " types are tively. The spindle 42 carries at its lower identical, except in the ratios of the airscrew end a metal roller 56, mounted on a bar 57, reduction gear. Both are based on the " X.F." pivoted to an arm 58. The roller is pressed on high-performance service engine, but have a super t o the resistor by a spring 59, th e arm 57 being charger of moderate speed, the impeller running at balanced b y holes formed in it, and the contact 70 per cent only of the " X.F." impeller speed, t o the moving element being made by arms 60 permitting full throttle operation at approximately 5,000 ft. They have recently undergone a type drawn against a collar 62 on the spindle by test which included a 50-hour run at maximum h.p. a spring 61. The winding 50 is mounted on a and maximum permissible r.p.m. Under cruising removable former 51, the wire being wound up conditions the fuel consumption is less than 23 g.p.h. and down on the inner surface of the former, and oil consumption below 5 g.p.h. They developed and looped into slots at each end, to obtain a 570 b.h.p. at 2,000 r.p.m. and 622 b.h.p. at 334,341 . Wireless signalling. Smith, minimum inductance. Studs 53 in connection 2,200 r.p.m. during the test. R. T., Royal Aircraft Establishment, South with the tappings to the winding on the outside Characteristics:— Farnborough, Hampshire. July 30, 1929, of the former make contact with spring Bore, 5½ in. ; stroke, 7½ in. ; total swept volume, No. 23363. [Classes 37 and 40 (v).] members 54 which in turn are connected to 1,753 cu. in. (28·7 litres); airscrew speed, Bearings, determining; resistances.—In a "X.F.A.M.," 0·656 engine speed, " X.F.B.M.," external sockets. In use the potentiometer is wireless direction-finder, the effect of reception 0·5 engine speed; rating at normal r.p.m., 555 b.h.p. in continuous rotation by connection to a on a loop aerial is neutralised by the effect of at 4,000 ft. ; power at maximum r.p.m., 600 b.h.p. windmill or other motor, and the position of reception on another aerial, so tha t the orien at 5,000 ft. th e pointer is noted when the zero signal is tation of the loop aerial relative to the trans obtained. If red the pilot turns to port, or mitting station is indicated by a device serving if green to starboard to make the transmitting to vary the relative effect of the two aerials on station, and the angular deviation is directly the receiver. A loop aerial 1, Fig. 1, for use on readable. The apparatus may be modified to aircraft, and arranged athwartships, is con nected through coils 2, 3 to the ends of a potentiometer resistance 4 th e sliding contact 8 of which is connected to earth, the coils 2, 3 being so coupled to the grid-circuit coil 5 that the open-aerial effect of the loop 1 is zero when th e moving contact of the potentiometer is central. If the loop is not at right-angles to the direction of the transmitter a signal will be heard, which may, however, be neutralised by adjusting the potentiometer tapping which can, therefore, be calibrated in terms of th e angle the loop is making with the direction of the trans mitter. The potentiometer 4 should have as * These abstracts of complete specifications of Patents recently published are specially compiled , by permission of H.M. Stationery Office, from abtidgements appearin g in the Patent Journal. Printed copies of the full specifications can be obtained from the Patent Office, 25. Southampton Buildings, London, W.C.2. price one shilling each. Except wher e otherwise stated, the specification is unaccompanied by drawings if none is reproduced.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Dec 1, 1930