Lean540,

If you're experiencing porpoising, you might have a significant CG issue...remember these Extras and Edges (Caps, Yaks, Sukhois, Giles, Lasers, etc) are not like your garden-variety fun-fly birds...their CG location is vital. The smallest shift from "ideal" may yield flight characteristics you won't like. So if you are significantly off...like an inch or more, your plane may barely be flyable.

If you built the plane properly, and your CG is pretty much on the spot, this plane will groove like a much larger craft.

Good luck.