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Aviation History
1957
1957 - 1455.PDF
4 October 1957 DISTANCE TO 50 (t GROUND RUN 1J0 140 150 160 170 TAKE-OFF WEIGHT (ibxiOOO) (Aboye) Take-off performance of the Argus: 15 deg flap; 3J00 b.h.p. at 2,900 r.p.m.; Vl.o. l.JVsi, Vcl 1.2Vs,, accessory allowance, 50 b.h.p. per engine. (Below) Climb performance. Normal rated power at 2,600 r.p.m. (four engines); no flap, landing gear retracted; accessory allowance, 50 b.h.p. per engine. Right-hand curves: maxi- mum level speed at various weights. CLIMB AT CONSTANT E.A.S.(kt) M1-5 146 5 150 5 WEIGHT (Ib) 110,000 130.000 150 000 10 20 SO MIN TIME TO HEIGHT (min) 260 200 VTIjctJ M0 5 10 / , 15 * MAX RATE OF CLIMB (ft/mm xiOOJ 20 airspeed. The spoilers increase manoeuvrability during attacks on submarines, and they are also valuable during asymmetric condi- tions caused by the launching of a heavy store from under one wing. The spoilers themselves are simple unperforated surfaces which are opened upwards about their leading edges (asymmetric- ally or together) by electric actuators in an overall operating time of 0.6 sec. From the pilot's viewpoint an interesting feature of the Argus is its rejection of "ram's-horn" aileron controls in favour of conventional wheels of surprisingly diminutive size. The Hobson- type q-feel simulator, supplied by Jarry, is retained in the elevator circuit, and is energized by a small auxiliary hydraulic system governed by a valve-assembly sensitive to indicated airspeed. The autopilot is the Bendix (Eclipse-Pioneer division) PB-20C [Flight, April 12 last] which is installed as an integrated auto- matic flight system, a special feature of which is close-tolerance altitude retention—essential for bad-weather operations close to the sea. One of the unusual features of the Britannia flying controls is that, should the aircraft be parked with the control-locks dis- engaged, the ailerons and elevators are free to droop. Moreover, although for ground-testing purposes it is possible to operate the elevators and rudder with the aircraft stationary—by opening up the inboard engines and thereby creating adequate slipstream—the Britannia ailerons cannot be properly operated on the ground unless the aircraft is taxied fast enough to create a relative airspeed of some 60 knots. Control position indicators are fitted in the Britannia flight deck. Canadair and the R.C.A.F. decided to redesign the circuits in order to permit pre-flight checks to be undertaken with the aircraft parked. The change was effected by arranging for the aileron locking cylinders to push both surfaces fully up, so that, when the locks are disengaged, the ailerons move downwards through their entire travel under the assistance of biassing springs. At the same time mechanical locking collets were incorporated in the locking cylinders, to ensure positive retention of the lock even in the event of dissipation of hydraulic pressure. Few changes were necessary to adapt the Britannia fuel system to the piston-engined Argus, apart from the switch to 115/145- grade petrol. Total usable fuel amounts to 6,688 Imp. gal, all housed in flexible cells within the wing box. The location of these cells differs slightly from that of the Britannia 100, owing to the outward movement of the inboard root ribs and extension into the outer wings (like the Britannia 305). The cells are self-sealing, and an inerting system (to offer some protection against incendiary weapons) is under consideration. Provision is made for a rigid auxiliary tank, with a capacity of approximately 500 Imp. gal, to be installed in the forward weapons bay. For increasing the take-off power of the engines a water-injection system is provided, fed from tanks in the upper part of the nacelles. In the design of the hydraulic system Canadair departed very considerably from the precepts laid down by Bristol. The British Messier system of the airliner operates at 4,000 lb/sq in, a pres- sure 1,000 Ib/sq in greater than the ruling level which has in the past been standard practice in North America. The R.C.A.F. were anxious to adhere to established hydraulic components for as long as possible, particularly in view of their considerable stock supplies of 3,000 lb/sq in components available throughout Canada. Accordingly, Canadair redesigned the system to operate at 3,000 lb/sq in, and the inevitable weight penalty (actually this was held to a mere 21 lb) was more than recovered by careful design. Further substantial changes were dictated by the specified minimum operating temperature of -65 deg F (15 deg F below the required limit of the British system) and the increased number of services requiring hydraulic actuation. To meet die increased demands there are both main and emergency systems which serve undercarriage retraction, braking and steering, control-surface locking and weapons-bay door actua- tion The main system is energized by two Vickers constant-dis- placement pumps of the 30-deg type (i.e., the plungers are inclined at this angle to the swash-plate, which is perpendicular to the drive-shaft), which are mounted on accessory boxes driven from the inboard engines. Each box is maintained at constant r.p.m. by a Sundstrand constant-speed drive, and the Vickers pumps deliver 7.1 Imp. gal/min at 3300 r.p.m. Pipe-joints and fittings are similar to the Ermeto flareless type, holding line weights to a minimum. The main reservoir is pneumatically pressurized to Continued on page 548, after double-page drawing o) the Argus)
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