No offense - but that engine is a bit of a dog. Not that they are bad engines - great for trainers, cubs, etc that don't require a lot of power. The best engine for the .46 UCD is a Saito 72.. the best for a UCD .60 is a saito 100. The OS engines are pretty good too, but heavier.

I had a .72 on my UCD .40 - total weight was 4.8 pounds... best 3D flyer I have ever owned, much better than the 60-size UCD.
Pretty inexpensive too... picked up the .72 used for $120

Don't use a ST or YS on those planes - they really don't like inverted mounting and/or vertical hovering too much without pumps which makes them very expensive...

DP