Heinrich Lanz HR 9
2 models in this series
Heinrich Lanz HR 9: heavy single-cylinder Bulldog from Mannheim, D 2531 and D 2539, 40.3 kW at 750 rpm, running on gas oil, lignite tar oil, diesel oil, paraffin oil or petrol
Heinrich Lanz AG, with its plant in Mannheim, built the Bulldog, a single-cylinder hot-bulb tractor that ran at low revs with high torque and could run on simple, varying fuels. This page collects the HR 9, recorded here as the D 2531 and D 2539; hot-bulb technology dispensed with a spark plug and a classic injector, making the machine insensitive to fuel quality.
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The register lists 2 versions rated at 40.3 kW from the single-cylinder engine at 750 rpm. Kerb weights range from 4,300 to 4,540 kg, lengths from 3,900 to 3,920 mm, widths from 2,160 to 2,500 mm, with a height of 2,150 mm. Gas oil, raw lignite tar oil, diesel oil, paraffin oil and petrol are recorded as fuel.
This multi-fuel capability was the central selling point of the Bulldog line: in times of scarce or expensive diesel fuel, farmers could switch to cheaper substitutes without converting the engine. The heavy, low-slung build also delivered high pulling power for tillage work.
When buying a used example, check the condition of the hot bulb and cylinder liner, the tightness of the cooling system, the state of clutch and gearbox, and corrosion on frame and wings; given the great age of these machines, spare parts are mostly sourced through Bulldog collectors and specialist restoration workshops, and a solid understanding of hot-bulb technology is essential for operation.
Sources: SpecCodex register, model data: Heinrich Lanz HR 9
Models
Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.
