Mikrus MR-300: the Polish microcar built by aircraft factories

The Mikrus MR-300 was a Polish microcar produced between 1957 and 1960, with the body built by WSK Mielec and the engine by WSK Rzeszów. It was designed as a cheap car for the masses, yet it ended up costing about fifty average monthly salaries, and only 1,728 examples left the factory.

Mikrus MR-300 at a glance

Figures follow the Polish Wikipedia article, which gives the engine details and equipment; the English article supplied the production total and the price context.

History of the Mikrus MR-300

A car for the masses, built by aircraft plants

At the end of 1956 the authorities decided to use the spare production capacity of the aerospace manufacturers WSK Mielec and WSK Rzeszów, which until then had made only aircraft and motorcycles. WSK Rzeszów prepared the engine drawings while WSK Mielec took charge of the chassis and bodywork, following the layout of the German Goggomobil. The projects were shown at the National Automotive Meeting at the beginning of 1957, and the first prototypes were presented in Warsaw on 22 July 1957. The new car was called Mikrus MR-300, the letters standing for Mielec and Rzeszów.

A simple formula

The idea behind the Mikrus was summed up as 4×4: four people, four wheels, a kerb weight of 400 kg and fuel consumption of 4 litres per 100 km. The engine was a two-stroke, two-cylinder, air-cooled unit of 296 cm³ mounted transversely at the rear, driving the rear wheels through a twin-plate wet clutch and a four-speed gearbox without synchromesh. The body was a two-door, four-seat monocoque with a 200 dm³ luggage compartment in front of the driver and passenger, reachable only from inside the cabin.

Popular, but expensive

Press reports of the time expected the Mikrus to become a very popular means of transport for a wide range of users, provided its price stayed within 25–30 per cent of a motorcycle of similar capacity. Interest was indeed great, but high manufacturing costs prevented the planned large-scale production. The car cost 50,000 złoty, roughly fifty average monthly wages, while the much larger Warszawa cost 120,000 złoty. Alongside the saloon, two convertibles were shown in 1957, but neither reached production.

The pick-up that never was

In 1960, as Mikrus production was coming to an end, the WSK Mielec design office prepared a pick-up prototype in ten days, answering a government directive for a small delivery vehicle. It could carry 200 kg and used the same wheels and suspension as the saloon; the load bay could be covered with a canvas hood on tubular hoops. The market was estimated at 100,000 vehicles, but like the convertible the pick-up stayed a one-off.

Design and features

• Rear-mounted two-stroke twin: 296 cm³ and 14.5 hp, enough for about 90 km/h.
• Monocoque two-door body: four seats and a front luggage compartment of 200 dm³.
• Very light: 472 kg with a load capacity of 228 kg.
• Heating from the engine: cooling air warmed the cabin; the side windows slid rather than wound down.
• Small 10-inch wheels: fine for town, less so on the roads of the late 1950s.

Mikrus MR-300 versions

• Saloon (1957–1960): the only version built in series, 1,728 cars in total.
• Convertible (1957): two examples were presented with the first prototypes, never produced.
• Pick-up (1960): a ten-day prototype for a 200 kg delivery vehicle, not built.

The Mikrus came from the same Świdnik and Mielec aircraft industry that produced the WSK M06 B3 and later the WSK M21W2 Dudek. More Polish vehicles are in the WSK collection.

Sources

• Mikrus MR-300, English Wikipedia: history, price, dimensions, performance
• Mikrus MR-300, Polish Wikipedia: design, engine, gearbox, equipment