RE: Li-po battery size for .40 sized 3d planes.
THERE ARE ALOT OF PACK CONFIGURATIONS. I WOULD SAY A 11.1V 4000-6000MAH (3S1P-LIPO)PACK WOULD BE A REASONABLE LIPO FOR THE MOTOR BEING RUN IN A .40 SIZE AIRPLANE. BUY A CHARGER CAPABLE OF CHARGING ATLEAST 4 CELLS. AS LIPO CONFIGURATIONS CONTINUE TO GROW THE MORE FLEXABLE THE CHARGER THE BETTER.