Some of the posters are comparing the other four stroke engines to the YS, which is not an accurate comparison as the YS is a Supercharged engine.

That YS will haul the .46 UCD around just fine.

As Robotech mentioned your only problem is to AVOID overspeeding the plane.

The UCD is a plane that is best flown SLOWLY, as it is a lightly built 3D flyer.

Use a 4W type prop on it, and you'll get powerful pull outs from 3D positions.

The plane flies at a crawl, and lands even slower.