Due to the fact that existing engines in the market did not fulfil the high standard of 3W-International GmbH, management decided to start their own project for a heavy fuel solution. In 2007, the first heavy fuel UAS-engines were designed. Several developments were made and tested until the R&D department decided on the final engine design. The crankcase was pre-heated for the cold start by using cartridge heaters. The air intake section and carburettor were modified, too. One-cylinder engines were fitted with a particularly shaped muffler with an integrated heat collector, which accepts cartridge heaters. The two and four-cylinder engines were fitted with a heat collector, designed to accept the suitable cartridge heater.
After the first prototypes had been produced, the engines were tested under various severe conditions. At the test-facility, the engines had to run without difficulties in an ambient temperature of +45°C, including restarts. To simulate low temperatures, a 5l tank with JET A-1 was stored at -18°C in the deep freezer overnight. Even given these conditions the engines were started without any problems.
The combination of these modifications and the new development constituted the breakthrough in heavy fuel technology. The engines proved their outstanding reliability during the extensive test runs – securing PERFORMANCE BEYOND LIMITS.
