Two 36-ft.-long Bus Chassis
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TWO new single-decker passenger chassis designed to comply with the new legal maximum length of 36 ft. have been announced by A.E.C., Ltd. Both models are based on the A.E.C. Reliance underfloor-engined chassis, and are to be known as the Reliance 470 and Reliance 590.
The Reliance 470 is, in fact, an extended version of the existing model built for the U.K. market. It has an 18-ft. 7-in, wheelbase, which is an increase of 2 ft. 3 in., and a modified front axle with a higher load capacity and increased wheel locks to allow the turning circle to be kept within the existing regulations which are, of course, unaltered despite the increase in maximum length. In all other respects the new model is the same as the earlier Reliance.
The A.E.C. AH 470 six-cylinder horizontal diesel engine is still fitted. This has a capacity of 7.685 litres and a maximum output of 126 b.h.p. at 2,200 r.p.m. Maximum torque is 335 lb. ft. at 1,200 r.p.m. Transmission is through a 151-in. dia, single dry-plate clutch and a five-speed synchromesh gearbox.
An A.E.C. AH 590 six-cylinder horizontal diesel engine is fitted in the Reliance 590. Maximum power output is 139 b.h.p. at 2,000 r.p.m. and maximum torque is 430 lb. ft. at 1,100 r.p.m.. Tranmission on the Reliance 590 is through a 15/-in. single dry-plate clutch and either a fouror six-speed synchromesh gearbox can be fitted. The latter has an overdrive top gear ratio and is intended for vehicles employed on coach or express passenger services. A maximum speed of 70 m.p.h. and a gradient capacity better than 1 in 5 is claimed when this gearbox is fitted. Wheelbase of the Reliance 590 is also 18 ft. 7 in., and the same front axle is fitted.
Both new models are available as bus or coach chassis with straight or dropped extensions to the frame. The majority of components on the new chassis and the existing Reliance chassis are interchangeable. Mean frame height is 3 ft. 3/ in. and front and rear overhang is 6 ft. 64 in. and 10 ft. 31 in. respectively. It is estimated that the minimum swept turning circle will be 69 ft.
In general, the new models are identical, apart from the engines and gearboxes. Braking on both is air-pressureoperated with Girling cam-operated leading-and-trailing shoe units at all wheels.
Either Clayton-Dewandre or Westinghouse air-pressure equipment can be fitted. Width of the front brake shoes on both models is 41 in., and the rear shoes are 6-in, wide on the Reliance 470 and 7-in, wide on the 590. This gives B22 a total brake lining area ; 618 sq. in. and 678 sq. ir respectively.
There is also a sma difference 'in the steering la: out of the two chassis. Th results in there being 51 tun of the wheel from lock t lock on the Reliance 471 compared with 61 turns in th case of the 590. Rear ax ratios of 4.7, 5.22, 5.87 ( 6.28 1 arc available on bot models with an addition; alternative ratio of 4.08 : 1 o the Reliance 590.
Standard tyre equipmer on both models is 10.00-21 14-ply tyres, and Ashanc exhaust brakes and automati chassis lubrication arc available as optional equipment.
Suspension on the new models, as on the existin Reliance, is through semi-elliptic leaf springs at the fror and rear. On both, the springs are 31-in, wide, the froni being 56-in, between centres, whilst the rears are 60-it between centres. Double-acting telescopic hydrauli dampers are fitted at the front axle.
There are differences between the two new models i respect of the fuel tank size and the exhaust system. Th Reliance 470 has a 25-gal. welded-steel tank, whilst th capacity of the fuel tank on the Reliance 590 is 32 gal. .1 both cases the tank is mounted on the nearside frame sid member. The exhaust system of the 470 uses 2-in.-di2 pipe, with 3-in.-dia. pipe on the 590. Recommende maximum gross vehicle weights are 11 tons and 121 ton for the Reliance 470 and 590, respectively.