September , 1934 AIRCRAFT ENGINEERING 243 BRITISH CIVIL AEROPLANES A Two- or Four-Engined Machine Adapte d to Various Uses H E Avro 642 has been designed as both der are balanced. The incidence of the tail- a twin-engined and four-engined plane is adjustable from the pilots' scats and model. is operated by the usual screwjack mechanism. When carrying sixteen passengers and bag Like the ailerons, the elevators and rudder are operated through a combination of steel tie- gage the twin Jaguar model has a cruising rods and stranded steel cables. A servo- range of 360 miles (580 km.) at 135 m.p.h. operated trimmer is fitted to the rudder. (217 km.h.). With standard tanks, the range can be increased to a maximum of 600 miles The fuselage frame is of welded tubular steel (965 km.) by reducing the payload. Further construction. All the tubing used is of round increased range can be provided by fitting section and is of a special welding quality. extra tanks. The fuselage is built in a single unit, braced by Separated from the passengers' cabin by a tubula r steel struts which are welded in position and by high-tensile steel wire. The process of communicating door, the pilots' cockpit is construction of the fuselage frame is such that, comfortably and conveniently arranged. Full side-by-side dual control is provided, with parallel motion pedals for the rudder and wheel PRINCIPA L CHARACTERISTICS Tw o Siddeley Jaguar, series VI.D, each developing 460 h.p . at control for the ailerons and elevators. A 2,000 r.p.m. central control box houses the tail incidence Spa n 71 ft. Bin . (21-72 in.) Heigh t 11 ft. 6 in. (3-51 m.) adjustment wheel, the throttle lovers and the Lengt h 54 ft. 6 in. (16-61 m.) brake operating lever. The entire windscrcen- Whee l track 15 ft. 10½ in. (4-85 m.) Win g area 728 sq. ft. ing is of triplex glass. The side windows Ailerons 44-6 sq . ft. alongside the pilots' seats can be opened and Tal l plane 47 sq. ft. Elevator s 40-5 sq. ft. arc arranged to slide vertically by means of a Fin 14-1 sq.ft. balance mechanism so tha t they can be opened Rudde r 24-8 sq. ft. .Mean chord of wing 10 ft. 7½ in. (3-24 m.) to any desired extent by a touch of the hand. Aspec t ratio ,. 6-96 to 1 The cockpit is situated in the extreme nose of Incidenc e 0 deg. Dihedra l 1-5 deg. the aircraft and the pilots have an excellent Tar e weight (with cabi n completel y furnished and lavatory fitted view in all directions. The emergency exit in an d equipped) 7,400 11). (3,356-6 kg.) W/ T apparatus (if fitted) and lighting .. 90 lb. (40-8 kg.) th e roof of the pilots' cockpit is filled with a Crew, 2 a t 170 lb . (77 kg.) 340 1b. (154-0 kg.) celastoid panel. Passengers , 16 at 160 lb . (72-6 kg.) .. 2,560 lb. (1,161-6 kg.) Fuel , 115 gallons (522-8 litres) 885 1b. (401-4 kg.) The cabin is 21 ft. (6-4 m.) long and 5 ft. Oil, 12 gallons (54-5 litres) 116 lb . (52-6 kg.) (1-52 m.) wide. The average height is over Baggage , et c 400 lb. (181 -4 kg.) Gross weight 11,791 lb. (5,348-4 kg.) 6 ft. (1-83 m.). Entrance to the cabin is through Maximu m authorised weight .. .. 11,800 lb . (5,352-4 kg.) a large door on the left-hand side of the machine, Maximu m speed a t sea level .. .. 160 m.p.h , (257 km.h.) Maximu m speed a t 5,000 ft. (1,524 m.) 154 m.p.h. (248 km.h.) and there is a folding step. During flight the Maximu m speed a t 10,000 ft. (3,048 m.) 149 m.p.h . (240 kin.h.) The pilots' cabin is a separate unit attached entrance vestibule becomes par t of the lavatory. Stallin g speed 64 m.p.h . (103 km.h.) Cruising speed a t 1,000 ft. (304 m.) .. 135 m.p.h . (217 km.h.) directly to the front end of the fuselage frame. The baggage compartment is entirely separate Best climbing speed 94 m.p.h. (151 km.h.) The undercarriage is in two separate units, and the door is on the right-hand side of the Bes t gliding speed 85 m.p.h . (137 km.h.) Best gliding angle 1 i n 9-3 each consisting of a half-axle attached to the fuselage. The sixteen passengers are accom Take-on run„.. ,„,„,, ,.,.,,„ (22.35 bottom longeron, a radius rod also attached modated in comfortable armchair scats, which .) 300 yards(274 in.) Landin g run (270 yards (247m.) to the bottom longeron and a shock-absorbing are quickly removable. Kate of climb at sea level .. .. 970 ft./min. (4-93 in./see. stru t which is approximately vertical and Tin e to 1,000 ft. (304 m.) 1-2 min. The Avro 642 has an unbraced cantilever Tim e to 5,000 ft. (1,524 m.) 6-4 min. whoso upper extremity is attached to the wing. rellexcd wing, which has continuous wooden Tim e to 10,000 ft. (3,048 m.) 166 min. Servic e ceiling 15,500 ft. (4,724 ni.) No rubber is used in the shock absorber, spars throughout its span, and wooden ribs. Ceiling on one engine 1,000 ft.(304 in.) which operates on the Oleo principle, sup There is no internal bracing and the whole of plemented by steel springs to take taxying the wing forward of the rear spar is covered when completed, all the tubes are hermetically loads. Twenty-six-inch Dunlop wheels fitted with a plywood skin glued and nailed to the sealed, and careful examination of specimens with 10-in. oversize high pressure Dunlop tyres spars and ribs. The wing structure is very cu t from the fuselages of similar aircraft after are used, together with Dunlop pneumatic completely protected . agains t the alternate long periods of service in all kinds of climatic wheel brakes, applietl simultaneously by a effect of rain end sun by a fabric covering, conditions has disclosed no sign of corrosion hand lever or individually by the normal which is glued to the upper surface, while on on the interior of the tubes, although no use of the rudder pedals. The tail wheel is the underside the joints of the plywood skin internal treatment has ever been used. This fitted with a low pressure pneumatic tyre and are scaled with linen strips. The portion of the is considered sufficient indication that internal is substantially mounted, with an efficient wing aft of the rear spar is made detachable to treatmen t is unnecessary. Externally, the shock absorber. The wheel is of the fully facilitate transport and is of built-up spruce frame is treated with two coats of oil under- costoring type, but is provided with a spring- lattice construction, fabric covered. The coating and two coats of cellulose finishing loaded device so that it maintains its normal ailerons arc long and of narrow chord and are lacquer. The cabin floor is of plywood on position during flight. of Frise balanced type. They arc operated stou t spruce frames, built in sections, which by tie-rods and stranded steel cables, the Each engine mounting is a rigid welded arc fitted into the bottom horizontal bays of cables being introduced at those points where tubular steel structure directly attached to the the fuselage frame, replacing the diagonal changes of direction occur, where they are used front spar of the wing. The wing structure is bracing at these points. in conjunction with large diameter pulleys. insulated from the engine by a fireproof bulk Spruce formers and stringers are used where head. The engine is faired into the wing so The tail is of welded tubular steel con necessary to give the desired shape to the fuse tha t it presents the minimum head resistance, struction throughout. The elevators and rud lage, and the external covering is of fabric. and Townend rings are fitted. Four-bladed wooden airscrews are used with geared engines and two-bladed airscrews with ungeared engines. All petrol and oil tanks are of welded aluminium, a form of construction which has been used most successfully for many years. All tanks are carried in cradles to which they are secured by flexible straps. The petrol tanks are mounted in the wing.between the front and rear spars, and the oil tanks in the leading edge of the wing, where they are cooled by the slip stream from the airscrews.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Sep 1, 1934