Hi guys,

Im a 7 years airplane RC pilot (GLOW) and im thinking on geting on this electric thing.

Mainly im interested on this 2 birds :

- Great Planes Super Sportster EP ARF 48" (GPMA1160 )
- Goldberg Tiger 400 Park Flyer ARF 39" (12081 )

... on the speed controller i think i dont have problem, but im not on the CELL PACK BULDING world so im looking for a battery pack already mounted ... are this batteries a good alternative for this aircrafts ? (the airplane claims for a 8 cell 1.100mah config, but i think this may work, or im wrong ?) :

Kokam 2000mAh 2-Cell 15C Super High Discharge (KOK2000-15C-2S-)

.. and this chargers ? :

- Great Planes ElectriFly Triton DC Comp Peak Charger
- Kokam 12V Li-Po Multi Charger 1-5 Cells

And the selected ( i think) speed control is :

Kokam Super 30 Lithium Polymer ESC 30 Amp

So i need help guys on selecting all this things ...

Thanks in advance ...

Pat

I see one major problem. If using a 2 Cell Lipo, you will have less power (voltage) than the 8Cell Ni-Cd. Although the 15C Kokam packs are great, you won't be able to pull much amperage from them on a stock 400 brushed motor. I don't know what kind of motor you are planning to use or what your budget is. I'll give you two scenarios.

1. Use a 400 Brushed motor/Speed Controller with an 8 Cell Ni-Cd pack and a normal Ni-Cd charger. Most affordable.

2. Use a Brushless 400 class motor/Speed control with a 3 Cell Lipo and a specialized charger like the Triton or the Kokam 402/502.

Here's the reasoning...A three cell Lipo (11.1) will burn up a brushed motor pretty quick, maybe even the first flight. Remember, it was designed for 9.6v. A 2Cell Lipo only has 7.4v. This would make it fly even worse than the 8 cell ni-cd. Also, spending a lot of money for a lipo battery AND a charger is a significant investment, one I feel is wasted without also going to a brushless motor.

I finally took the brushless plunge a while ago on a plane similar in size to the Tiger 400 you are considering with good results. Hopefully some others will chime in with some affordable motor/ESC choices. Mine was on the expensive side. I can share my setup if you wish, but first describe what you want from your plane and what kind of budget you have. This will help all of us help you make the best decisions.

Admittedly, you will be down a little on power by going with a 2-cell LiPoly instead of an 8-cell NiCd or NiMH. But, it's not as bad as it might seem on the surface. Here's why:

The NOMINAL (rated) voltage is 9.6V for an 8-cell NiMH, and 7.4V for a 2-cell LiPoly. Fully charged, the NiMH will read at least 10.4V (up to 11.2V), and the LiPoly will read 8.4V. Even worse, right? Hold on a second, we haven't fired up the motor yet!

With the motor running, you'll get what's called voltage depression on both batteries. Under full load, a properly sized 8-cell NiMH will drop to about 8.8V, while a properly sized 2-cell LiPoly pack will drop to about 8.0V. That's not a huge difference, less than 10%.

Well, lets go again,


If im interested on flying this mini Tiger airplane, which seems to be the best combo deal on motor and batts ? ... the performance i look for its just sport flying (loops, rolls, high speed passes near the floor, etc) ...

thanks,

Pat