Pond Flyer

I just finished building a Donald 4 Electric Seaplane from Hobby-Lobby. The package included an 8 cell 1700 mah SRC Nicad battery, jeti 45 motor controler, speed 600 8.4 V motor, Hitec CG- 340 field charger, and a seperate 4 AA battery pack for the radio and servos. The problem is: after charging the battery until it went to trickle charge I went to the lake, and after a practice taxie run the engine quit. When turned off and back on it would only give a short burst of power indicating a low flight battery. When a got home I checked the no load voltage on the battery. It was 9.87V, then I ran the motor until it would not give a burst of power when turned off, and on, (this only took about 45 seconds), and quickly measured the no load voltage 7.61V. The total run time on the fully charge battery was less than 5 min. This would indicate that the battery won't hold a charge. I am new to this and might be missing something. Any suggestions? By the way the plane jumped up on the step an skimmed along the surface in great form for about 100 Yards.

Pond Flyer

I think I have solved the problem. After completly discharging the battery, and recharging it the motor ran for a little over 6 min at full power. The speed 600 draws 11 Amps at full power, and 1.8 Amps at idle. The battery must not have been charged right the first time. I disabled the low voltage cutout on the controler because of the seprate power supply for the radio, amd servos. I should now have about 10 min. flying time. Is there a battery around 8 Oz that will give Me more flying time?
THANKS