I think maybe you misunderstood - it (apparently) cannot occur in rigid or semi-rigid 2-blade systems. I don't think our helis fall into that category as their blades are hinged and there is lag as the rotor spools up.

To be safe, I would take time to thoroughly inspect your setup to ensure that there is no balance issue before you proceed. Unless your Eagle is noticeably out of balance, I suspect that it is in fact ground resonance that you're experiencing. Did you make sure to pull your blades straight before spooling up? Have you checked that the blade grips aren't too loose, or too tight? As I said before, do not attempt to throttle through it once it has started, or I'm sure you will destroy your heli.

Keep in mind that I am also fairly new at this... I assume no responsibility if you wreck something!!