We now recommend the 7.2V motor with a 6x4 prop on an 8-cell KR-1400AE pack as
standard. Why? Because you do not have to be as careful with equipment
placement to achieve a balanced airplane. Systems using KR-600AE packs always
seem to need extra nose weight.
Another reason to use the KR-1400AE cells over the KR-600AE cells is because the
1400AE pack
allows up to 11 minutes of full throttle motor run time as
compared to about 5 with a 600AE pack.
We also feel that the 8-cell system provides slightly more power than the
7 cell system in spite of the weight of the extra cell. If your charger can't
handle an 8-cell pack, however, the 6V motor with 5.5x4.5 prop and 7 cell KR-1400AE
pack is more than adequate.