2100 mah battery?

[njfsu]

I have been trying to use a 2100 ma li-po battery, and have ensured the center of gravity is about 3.25 inches behind the leading edge, but the flight is erratic, and cannot be fixed by trim. i change to a 1320 with the cg at the same point, and it flies beatifully. is it possible to fly with the larger battery or should i be happy with the 1320? if its possible how can i fix the errqatic flight (will drop the wing either right or left even if i trim it in opposite direction, and will climp or dive again reguardless of trim). thank you for any help.

And let me add, the plane is awesome (with the 1320 of course).

[paulg]

The CG should be the same 3.5 to 4".

[tdarst]

What I found flying 2100 vs. 1320 is simply that the stall speed is significantly higher with the heavier battery. This makes sense, as since the all-up weight is much higher, then required lift to maintain flight and avoid stall is much higher, too. With all else constant, lift is a function of speed. I fly with my CG about 4" behind the leading edge, with either pack. My selection of packs is primarily premised on wind speed; I only use the heaver pack when the wind is 8 to 10mph or higher (Have flown in as much as 20mph winds with the heavier pack - the Edge much easier to handle with the extra weight in these conditions).