Legend Aircraft has selected the Superior Air Parts Gemini diesel engine as a factory option for the Legend Cub light sport aircraft. The 100-hp diesel engine will be available for both the wheel- and float-equipped factory-built Legend Cubs as well as the kit-built version. Pricing for the diesel option has not been set yet, but should be roughly comparable to other engine options, according to Legend Aircraft president Darin Hart. The diesel engine fits into the same cowling on the Legend Cub, so not modifications to the cowl will be needed.

AirVenture Oshkosh visitors can see a mockup of the engine installation in a Legend Cub at the Superior Air Parts display. The engine weighs nearly 200 pounds installed and should deliver performance similar to the avgas Continental O-200-powered Legend Cub, but with 20 percent lower fuel burn and lower emissions. “We are especially excited to offer the diesel option to our owners who operate in remote locations or in parts of the world where 100LL avgas is expensive or difficult to find,” said Hart. “We think it will improve our sales.”

The the three-cylinder Gemini engine has a “uniflow” design with two opposing pistons per cylinder. While it has roughly the same profile as a Rotax 912, the uniflow design makes for a smaller engine compared to existing engines, giving it a power-to-weight ratio advantage, according to Superior. Deliveries of the engine to the experimental market are expected in early 2016. Superior is developing a family of diesel engines in the Gemini line, ranging from 100- to 600 hp.