Enter the Proctor
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A NEW 5-6.
-ON OILER Perkins P6 Engine and Moss Gears Figure in Specification of 3o-rn.p.h.-class Goods Vehicle SOME weeks ago we were able to give the first news of the introduction of a new oil-engined 5-6-tonner to be known as the Proctor Diesel Mk. T. We have now had an opportunity of inspecting and handling a prototype vehicle, and are thus able to give the first detailed technical description of it.
The specification is interesting, in that it includes the well-known Perkins P6 oil engine, a five-speed gearbox, Layrubjointed drive shafts, and Girling twoleading-shoe brakes, with Lockheed hydraulic actuation in conjunction with a Clayton Dewanclre vacuum servo.
Frame members are of pressed-steel channel section, ,measuring 8 ins, at the deepest point, by 21 ins. by -& in. The side members are braced by five crossmembers, the side members in the region of the forward anchorage of the rear springs being substantially reinforced.
The Perkins P6 oil engine is a sixcylindered unit having a bore of 8811 mm. and a stroke of 127 mm., and it is rated to give an output of 70 b.h.p. at 2,200 r.pari„ with a maximum torque of 184 lb.-ft. at 1,000 r.p.m. The cylinder block and crankcase form a one-piece casting in chromium-iron, the valves and tappets being housed in the detachable cylinder head. The rockers are mounted on top of the head and are operated direct by a three-bearing camshaft, which is carried high up on the off side of the block.
C.A.V. fuel-injection equipment is used, the fuel pump, which is pneumatically governed, delivering to atomizers of the two-spray type. The engine is rubber-mounted at the rear on a semicircular cross-member. The anchorage at the front is to a chassis crossmember, through a metal cradle member. The form of mounting adopted eliminates unit-frame vibration.
A 12-in. Borg and Beck clutch, of tale single dry-plate type, takes the drive to a unit-constructed four-speed-andoverdrive Moss gearbox, in which provision is made for fitting a power takeoff. The basic gear ratios provided are: 6.55, 3.6. 1.81 and 1 to I, the overdrive ratio being 1 to .818. The reverse ratio is 5 to I and the back-axle reduction 7 to 1.
A two-piece Layrub-jointed propeller shaft takes the drive to the rear axle; the intermediate bearing, located in the • ar centre cross-member, is self-aligning. In an unloaded condition the rear propeller shaft assumes an angle of about 4i degrees, which flattens out to about I degree when the vehicle is loaded.
The fully floating rear axle is spiralbevel driven, the differential drive-pinion and wheel hubsbeing mounted OR heavy-duty taper-roller bearings. Suspension is by long • semi-elliptic springs having silicon-manganese-steel leaves. The front-axle bed is a high-tensilesteel drop forging of I section, the wheel hubs being mounted on taperroller bearings. The tubular tie rods have ball-type pins which are of the self-adjusting type.
As previously mentioned, the brakes are of the Girling two-leading-shoe type. The means for operating them is the Lockheed hydraulic system, a Clayton Dewandre vacuum servo making for maximum application with a minimum of effort. The hand brake, as is usual, takes effect on only the rear wheels. The front-wheel brake drums measure 14 ins. by 2 ins., and those on the rear wheels 16 ins. by 3a The pressed-steel disc wheels have single locking rims and are each secured by eight nuts. Heavy-duty 34-in. by 7-in. tyres are fitted to all wheels, with, of Course, twins at the rear.
A Manes double-roller-type steering box is used, in conjunction with a 20-in. diameter steeriag wheel. Exceptional ease of steering is claimed for the Proctor, and this we can confirm after a brief period of • handling. The steering, whilst being low-geared, is not . unduly so, and tbci vehicle can be taken around sharp bends and generally manceuvred with an absolute minimum of effort. The 'Perkins engine proved exceptionally snappy in pick-up, the machine, which, admittedly, was unladen, getting away in third gear without the slightest hesitatidn. '
As to the general all-round perform an= of the Proctor under full load conditions, we hope to be able to publish a full road-test report at an early date.
A Lucas constant-voltage 12-volt dynamo supplies the current for lighting and starting, the starter motor being of C.A.V. make and of the axial type, with solenoid switch. A feature of the electrical equipment is the installation of a Simms control panel, which makes for ease of servicing.
The accompanying illustrations, which are of the prototype machine, show it without fenders. These are to consist of triple bars and will be in chromium finish. Holding 22 gallons, the fuel tank is carried on the near-side frame mem
ber. We understand that the very satisfactory figure of 16 m.p.g. is being obtained under fully laden running conditions.
Leveroll Drivers' Seat
The cab on the machine we inspected provided excellent visibilitarc and as the driver's seat is of the Leveroll type, affording adjustment ll'oth fore and aft. and up and down, a. comfortable driving position can readily be obtained
It should he pointed out that the vehicle comes sseq within the 3-ton unladen class, so that full advantage can be taken of the power available in the Perkins engine, in conjunction with the useful overdrive ratio. These features have not been introduced without due regard for a really efficient braking system..
General dimensions are as follow;— Wheelbase, 13 ft. 8/ ins.; track, front, 5 ft. 4.t ins.; track, rear, 5 ft. 4* ins.; frame length, 20 ft. 8 ins.; rear overhang of frame, 5 ft. 2 ins.; frame length behind. cab, 16 ft, 0/ in.; frame width, 2. ft. 8i ins.; frame height, loaded, 2 ft. 7* ins.; ground clearance under rear asle, loaded, 9 ins.
The maker of the vehicle is Proctor Springwood. Ltd.. Proctor Works, Mousehold, Norwich.