You must be off in your estimation of the amount of weight required to balance the model. The Thunder Tiger Sport only weighs about 5 1/2 pounds complete. There is no way that his model could require 8 pounds to balance properly. Even one pound would be grossly extreme.

That said, be sure that you have all of the radio components moved as far forward as possible before attempting to add weight to the nose. If the Sport has the same clamping motor mount system that the Tiger Trainer has, you can move the motor forward to the stops. Be sure that you are locating the C/G properly.

This model should be very close to the balance point without the addition of any weight if assembled properly and if all components are located forward. Good luck with the model.