Ursus C-451: the Bulldog made easier to use

The Ursus C-451 was the modernised version of the C-45, built in Warsaw from 1954 to 1959 and then in Gorzow Wielkopolski until 1965. The basic Bulldog engine stayed, but petrol starting, a hydraulic lift, a headlight and a canvas cab made the old design easier to live with. In Warsaw alone 50,000 were built.

Ursus C-451 at a glance

The Polish and English Wikipedia articles agree on the main facts; the detailed technical data comes from the Polish page.

History of the Ursus C-451

By the early 1950s the C-45 was ageing, and modernisation produced the Ursus C-451 in 1954. The nickname was the sagan on rubber wheels, a reference to the earlier C-45 and to the pneumatic tyres that had replaced steel wheels. The changes were aimed at easier operation and better usefulness rather than at more power.

The most important change was petrol starting. A small petrol tank of 5 litres was built into the 100-litre fuel tank, separated from the remaining 95 litres of diesel by a partition; the engine was started on petrol, warmed up and then switched to diesel. The injector received a closed construction, the cooling fan was made more efficient, the front axle bracket was strengthened, the crankshaft was surface-hardened, and a working headlight was added.

For fieldwork the C-451 gained a hydraulic lift for mounted implements, and for the road it gained rear fenders, a canvas cab on a metal frame with a fixed windscreen, and a road overdrive. This was an inverted reducer that doubled the number of gears from 3+1 to 6+2 and raised the maximum speed to 16.7 km/h. The result was a tractor that could finally travel between farms at a reasonable pace.

The engine remained the large single-cylinder two-stroke semi-diesel of 10,300 cc, producing 33 kW at 650 rpm. It was simple, tolerant of poor fuel and durable, but heavy, noisy, thirsty and awkward to service. It was also poorly suited to row-crop work, and the C-451 was widely criticised as too heavy and as using twice as much fuel as foreign tractors of the same class.

Production in Warsaw ended in 1959 after 50,000 tractors. Output had already fallen: 7,800 in 1956, 5,900 in 1957 and only 3,500 in 1958, while hundreds stood unsold at the factory because state farms were not ordering and individual farmers found the machine of little use. The technical documentation was handed to the Zaklady Mechaniczne in Gorzow Wielkopolski, which built the C-451 from 1960 to 1965. About 6,000 C-45 and C-451 tractors were exported to Brazil, China and Korea. A restored example from Rusocin was shown publicly on 11 November 2014, and the type appeared in the Polish television series Ranczo.

Design and features

• Petrol starting: a 5-litre petrol tank inside the 100-litre tank, with a switch to diesel once warm.
• Hydraulic lift: mounted implements became possible for the first time on this design.
• Road overdrive: an inverted reducer giving 6 forward and 2 reverse speeds and 16.7 km/h.
• Canvas cab and fenders: better protection for the driver than the open C-45.
• Simple but thirsty engine: tolerant of poor fuel, yet heavy, loud and fuel-hungry.

Ursus C-451 versions

• C-451 (1954–1959): Warsaw-built standard model.
• C-451 (1960–1965): production moved to Gorzow Wielkopolski.
• Road version: with the overdrive and 6/2 gearbox for transport work.
• Restored examples: one at Rusocin returned to use in 2014 after standing on a plinth.

The C-451 was the modernised successor to the Ursus C-45, and the next generation of light tractors began with the Ursus C-328. More tractors are in the Ursus collection.

Video: Ursus C-451 at Rusocin

Video by VadimOnTour on YouTube.

Sources

• Ursus C-45 and C-451, English Wikipedia: 1954 modernisation, Warsaw production total
• Ursus C-451, Polish Wikipedia: changes, fuel system, production decline, technical data