If need be, also with salad oil!
For many years, they were favourites in farm fields until they were gradually replaced by modern diesel tractors: tractors fitted with a hot-bulb engine were already being used at the start of the 20th century in agriculture where they represented an inexpensive and practical alternative to steam engines. The exhibition "Hot-bulb legends" at RETRO CLASSICS® STUTTGART will evoke the great age of the simple, but extremely robust machines which managed to hold their ground in Germany against technical superior competitors right up the middle of the 1950s.
"In particular, the rudimentary technology is now still fascinating," enthused Hubert Flaig from the Württemberg Bulldog and Tractor Enthusiasts' Club, which is organising the special show. "The first hot-bulb engines did not have a gearbox, a starter motor or spark plugs. The hot bulb was preheated using a heating lamp over a naked flame. When the bulb reached the required temperature after around five minutes, a valve was opened and fuel was injected. The engine was then started by means of pendulum movements of the flywheels against the compression resistance. Admittedly, this was rather cumbersome."
However, the majority of single-cylinder veterans are extremely undemanding: "Early hot-bulb tractors were powered by almost everything that was combustible," said Flaig. "This was often a crucial criterion in making a purchase since there was still no filling station network and the quality of the available fuels was extremely risky at times. If need be, these engines also ran on salad oil."
The hot-bulb engine, which was manufactured for the first time in 1891 by Richard Hornsby & Sons , started its triumphal march in the English town of Grantham. It enjoyed further success in Sweden, Italy and France before finally arriving in Germany. The exhibits to be presented at RETRO CLASSICS® will also include a Lanz Bulldog HL12 from the 1920s, whose type designation was adopted in common parlance in many places as a synonym for farm tractors. Anyone wanting to see this rustic technology should attend one of the three daily demonstrations on the stand of the Württemberg Bulldog and Tractor Enthusiasts' Club in Hall 8 where the "original Lanz" will be started very loudly.