Foden Developments BY R. D. CATER TWIN-STEER TRACTIVE UNIT :
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THOMPSON RETARDER : LONG STEEL CARRIER WHILE at Fodens Ltd., Sandbach, last week 1 learned details of VV three interesting developments, which are illustrated here. Seen above, an adaptation of the Foden crane carrier chassis has been developed as a load-carrier for T. A. Bulmer and Co. Ltd.. of Middlesbrough. and is already in service. A 28-ton-gross eightwheeler, it has the low-slung crane carrier cab forward of the engine. with the floor-line about 18 in. above the ground. The engine is mounted in the conventional "rigid " position, which makes for a slight restriction ot load-floor space, but this is no great disadvantage as the unit's prime use is to carry heavy sections for Dorman Long (Steel) Ltd.
The low cab enables long steel to be carried without needing a high bolster and thus the unladen weight and c. of g. arc kept down, while the need for extensive chaining to keep the load tram slipping is eliminated. Both centre and rear bolsters are detachable to allow general cargoes to be carried on return. The vehicle is 35 ft, long.
der with compressed air, hydraulic oil is forced into the turbine casing of the unit, so loading the driven stator. According to the pressure applied to the loading cylinder (controlled by a hand reaction valve in the cab) the quantity of oil in the casing can be varied; the more oil, the more retardation.
The unit is mounted on the rear of the differential worm-shaft and has its charging cylinder mounted at some convenient point on the chassis frame. When the unit is not in use the revolving member centrifuges the bulk of the oil out of the casing and back into the circuit where it is continuously passed through a heat exchanger cooled by the engine coolant.
Maximum operating temperature is said to be 300F, and when the unit was tested by Fodens it was found that, when descending the Macclesfield side of the Cat and Fiddle at 30 tons g.t.w. it held the road speed down to 15 m.p.h. without overheating.
Third development is a twin-steer tractive unit soon to be completed for the Glasgow company of James 14emphill Ltd. Powered by the FD6 Mk. VII turbocharged two-stroke. it is intended for operation at 32 tons gross with a Butterfield double-cone. single-compartment 5.000 gal. tank on York RG 5A tandem-Axle running gear. Payload is expected to be in the region of 21 tons.
The twin steering axles are spaced at 4 ft. 6 in. centres and the overall wheelbase of the tractive unit is 12 ft. 3 in. The fifth-wheel centre will be 2 ft. 5 in. forward of the rear axle.