It sounds like you're just sticking things together in the hopes that it might work.

The best course of action when designing your first electric airplane is to do your homework. Learn about Volts and Amps, as these are the most important values in determining whether your plane will fly or not. A motor calculator program like MotoCalc can help in the early stages of learning. You can get a free 30-day trial at http://www.motocalc.com. Another online calculator at http://brantuas.com/ezcalc/dma.asp will give you a rough idea of how many Amps a particular setup will draw.

I ran the numbers on your intended power system, and they do not look good. The current with a 9x6 prop is 11.67 Amps, and 13.6 Amps with a 10x7!!! Neither that SkyScooter battery, nor that Speed 300 motor will last long at that level of current! If, as I suspect, you are using the Sky Scooter's Speed 400 (FOUR hundred) motor and stock 3:1 gearbox, the current levels are much more manageable. You simply need a battery with a higher mAh rating to get longer flight times.

Your plane has a wing area of 338.25 square inches. That's a pretty good size for a Speed 400 floater. If you can keep the all-up weight under 22oz, that's with receiver, servos, battery, motor, gearbox, etc., it will fly really well, and probably thermal like a sailplane.

For a battery, the only way to fly with a Speed 400 is 8 cells. I recommend an 8-cell pack of Sanyo 600AR or 600AE NiCd cells, or an 8-cell pack of HECELL NiMH cells. Many online vendors can sell you the battery packs, all pre-wired. Check out the vendor section at http://www.ezonemag.com. Remeber that you will also need an appropriate charger. The timer charger that came with your SkyScooter sucks in the first place, and it won't charge an 8-cell pack. I recommend the Hitec CG-340 for light-duty electric flight. It can also double as a charger for your transmitter NiCds.