Otto Gaiser Muli
1 model in this series
Otto Gaiser Muli (1951): single-cylinder motorised trailer unit with an air-cooled diesel engine, a rated speed of 1,850 rpm and only one unit ever built
The Muli from Otto Gaiser was built in 1951 as a motorised trailer, a working machine that housed its drive unit in a trailer-like body rather than a classic tractor frame. According to available records, only a single unit of this vehicle was ever made.
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The air-cooled single-cylinder diesel engine displaces 763 cm³ and runs at a rated speed of 1,850 revolutions per minute. The rear wheels are driven through a simple gearbox with two forward gears and one reverse. At an empty weight of 690 kg, the Muli was among the lightest motorised tow units of its time.
The motorised-trailer layout was a design idea of the early post-war years, aimed at creating a simple tow unit for small holdings with minimal material use; it differs from the classic implement carrier, where attachments are mounted between the axles. The air-cooled single-cylinder engine needed no radiator or water pump, making it easy to maintain.
As a one-off, the Muli is not a vehicle that turns up on the used market; should a surviving example exist, it belongs in specialist hands and in a collection of historic farm machinery. With such a rare air-cooled single-cylinder engine, checking the cooling fins and the cylinder gasket before any start-up is essential. Original spare parts for a one-off prototype like this do not exist, so any repair inevitably means custom-made replacements.
Sources: SpecCodex-Register: Kennwerte des Modells Muli
Models
Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.