What Spaceclam says abut LiPo is correct. What he failed to mention is the cost. LiPo batteries and chargers ARE EXPENSIVE, especially compared to NiCAD/NiMH.

I would suggest the following:

1. Remove any extra weight you may have put on the plane to balance it.

2. Balance the plane by shifting the battery pack. This MAY mean you will need to use a #11 Exacto blade to enlarge the battery opening so the battery can slide further back. The instructions should tell you where to balance it. If the instructions do not give a balance point, measure the WIDTH (chord) of the wing next to the fuselage. Divide by 3 and you should have the distance from the leading edge of the wing for a starting point to balance (you can adjust the CG after if it doesn't perform the way you want). A "balance machine" can be easily made. Get a piece of 2x4 about 12" long and 2 pieces of 1x2 about 12" - 18" long. Nail one piece of the 1x2 vertically (on edge) to each end of the 2x4 (center the 1x2 on the 2x4). Get 2 1/4" dowels 12" long and 2 tapered rubber erasers (the type that go over the end of a pencil). Measure the width of the fuselage. Add 1/2" to the measurement and divide by 2. Mark this measurement on each side of the center of the 2x4. Drill a 9/64" hole at each location. Insert the dowels with the erasers in the holes Use a magic marker and put a mark on the underside of the wing at the balance point. Set the plane on the erasers and move the battery pack until the plane is level. Put a mark on the battery pack AND the plane to mark the location.

3. Make sure the battery pack is fully charged. If your charger is a "timer" type, you may want to investigate getting an inexpensive "peak" charger to insure the pack is completely charged. Dymond has one that automatically detects the number of cells in the pack (4 - 8 cells) and will charge NiCAD and NiMH. It costs about $30.

4. I suggest using the 8 cell pack. It will provide a little extra "zip" to the motor. If you haven't "run the motor in" I suggest doing it. Running the motor in is easy. Take the prop off the motor. Submerge the motor in a container of water. Hook up one D cell directly to the motor and let it run until the battery runs down. This will seat the brushes to the commutator in the motor without arcing and possibly damaging the commutator. If the commutator is damaged it will affect the power of the motor. If you can not get at the motor to wire a D cell to it, charge the battery pack, remove the prop, submerge the motor and run it at 1/2 throttle for about 5 minutes.

5. The 1060 prop will provide more thrust, but less top speed. The 1080 prop will give you a better top speed, but less thrust. I suggest starting with the 1060 prop and if that doesn't provide the performance you want, move to the 1080.

The plane should now fly. It will be slow and you will have problems if there is wind. Be sure you hand launch the plane, and launch the plane level - do not launch it nose up or down, be sure the throttle wide open.

Hope this solves your problems.