A couple of more objectives were added: The engine should be direct drive, air cooled and be able to run on both AVGAS and MOGAS with ethanol.

ROPA.BE is a metal turning and milling company making engine parts, while DR Tuning works in the motor racing arena.

[3] After a few years of development and testing of several prototypes the first UL260i 72 kW (97 hp) engine was installed in an aircraft (a Lambert Mission 106).

After proving[citation needed] the engine reliability on the ground and in the air, the project was merged into an official company structure.

In 2017 Sonex Aircraft introduced their "B" models with slightly larger fuselage giving room for more engine options.

[6] ULPower produces a range of direct drive air-cooled horizontally-opposed engines with multiport fuel-injection and FADEC.