New Czech Models Have
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Air-cooled Engines
AIR cooling is featured prominently in Czechoslovakia's latest lorries and buses. The four-wheel-drive Tatra T805, a 2f-ton military-cum-commercial vehicle, has a 24-litre V-8 petrol engine developing 75 b.h.p. at 4,200 r.p.m. Of over-square design, it has a 6.5 to I compression ratio and two Solex downdraught carburetters. The shrouded cylinders are cooled by a pair of beltdriven axial blowers.
An unusual aspect of this power unit is the location of the single camshaft high in the V between the two banks of cylinders, the valves being operated by short push-rods. The weight of the engine is 350 lb., made possible by the use of aluminium for most of the major castings and pressings. •
I.F.S. All Round
The chassis of the T805 is based on Czechoslovakia's traditional central tubular backbone which houses the propeller shaft; all wheels are independently sprung. Axle design is similar to that in the 10-ton Tatra I 1 1 in that no universal joints are used in the entire transmission system.
The inboard end of each half-axle terminates in a crown gear which meshes with one of the two pinions carried on short, coaxial shafts from each differential. With vertical wheel deflection the gear swings round its pinion and correct mesh is always maintained. Suspension is by torsion bars, and power is transmitted through a four-speed gearbox and two-speed transfer case to the front and rear differentials.
A forward-control cab and dropsided body are bolted to support mem bers on the tubular spine. Unladen weight of the T805 is 6,050 lb., overall length 188 in., width 89 in., and height 105 in. Top speed is said to be 45 m.p.h. and average fuel consumption at the rate of about 14 m.p.g.
To power the new rear-engined Karosa 35-scat bus, Czech engineers have cut down the air-cooled 12-cylindered oil engine used in the Tatra I 1 1 to make a 9.9-litre V-8 developing 125 b.h.p. at 1,900 r.p.m. Three camshafts operate the overhead valves in the light-alloy cylinder heads. Twin shafts for the exhaust valves are carried along the outer sides of the two cylinder banks. The third one, common to all inlet valves, lies at the base of the 75 -V, and this drives the two tuel-injection pumps.
The all-steel body is of integral construction, giving the three-axled bus an empty weight of 15,350 lb. and allowing a full laden weight of 23,700 lb. Overall length is 377 in., width 94 in., and maximum wheelbase 190 in.