Engine Cooling

Maybach claims a rotating disc that imparts velocity to the liquid and leads it through pipes — and which by its rotation also generates wind and evaporation. Note both jobs.

Fill two identical vessels with 300 ml of warm water each (about 60 °C). They stand for two equally hot engine cylinders.

Read both temperatures and note the time. They must agree to within 1 °C or the comparison is worthless.

Cut a 60 mm disc from heavy card and glue on four straight radial vanes. Fit it to the shaft of the gear motor.

Connect the gear motor to the battery holder with crocodile clips and check the direction of rotation.

Run the disc half-immersed over the second vessel. The first is left untouched — it is the control.

Measure for 15 minutes. Keep a table: time, still vessel, circulated vessel.

Set the disc in a card ring with a side outlet and attach a tube. When it turns, water is flung outward and flows away through the tube — a centrifugal pump.

Wind the tube around a copper pipe — the "cylinder" — and lead it back to the vessel. The water now runs in a loop: circulating, not merely stirring.

Stand the copper pipe in hot water and run the circuit. Measure the pipe temperature with and without circulation — flowing water carries the heat away, standing water does not.

Hold your hand beside the disc running dry. It generates a clear airstream — exactly the wind Maybach names in the claim.

Hang two damp cloths, one in front of the running disc. After 10 minutes touch both: the one in the airstream is colder — evaporation removes heat, and wind speeds it up.

Plot temperature against time for both vessels. The gap between the curves is precisely what stops the engine seizing.

The patent. US 499,302, "APPARATUS FOR COOLING LIQUIDS EMPLOYED IN MOTORS AND COMPRESSORS", granted 13 June 1893, filed 15 October 1892, to Wilhelm Maybach of Cannstadt. The specification sets out a rotating disc that imparts velocity to the liquid and conveys it through pipes to the cylinders, while the same rotation generates wind and promotes evaporation so the liquid is cooled on its way.

🔴 This is not the carburettor. Numerous sources cite 499,302 and 668,111 as "Maybach's carburettor patents". That is wrong: 499,302 expressly claims a cooling apparatus. Maybach's 1893 spray-jet carburettor is a separate invention with its own protection. Nor is it the famous honeycomb radiator, which came around 1900 for the Mercedes 35 PS. Anyone citing a patent number ought to have read the claims — in this programme that has become the rule rather than the exception.

Why cooling was the problem at all. A petrol engine converts only part of the combustion heat into work; the large remainder must go somewhere, or the oil burns and the piston seizes. The first motor cars simply boiled their cooling water away and had to be topped up. A circuit that carries the heat off and cools the liquid again on the way turns a demonstration engine into a machine for long journeys.

Two jobs, one moving part. The disc is pump (step 8) and blower (step 11) at once, and it exploits evaporative cooling as well (step 12). For a motor carriage in 1892 every part saved counted twice: less weight, less wear, less to fail on the road. That same centrifugal action drives the water pump in every car engine today — only now it sits in a housing and is driven by a belt.

Wilhelm Maybach (1846-1929) was Gottlieb Daimler's designer and was later called the "king of designers". The work at Cannstatt produced the high-speed petrol engine, the spray-jet carburettor and finally the Mercedes 35 PS of 1901 — with honeycomb radiator, carburettor and circulating cooling, everything invented here separately brought together in one vehicle.

An honest placing. Maybach did not invent water cooling — steam engines and stationary engines had long been water-cooled, usually by thermosiphon, with no pump at all. The claim in this document is narrower and more interesting for it: a rotating disc that combines delivery and re-cooling in a single component.