Originally Posted by sandal
I have flown glow and petrol powered planes for 15 years, but never anything electric. I have finally decided to convert my Blue Phoenix to electric, and a bit of advice would be welcome.
The Blue Phoenix is a two meter polyhedral balsa glider, very similar to the Gentle Lady. I want to add a motor system to get it up to thermal altitude. Nothing fancy, just enough to make it climb gently.
How do people manage battery capacity during thermal flights? Should I use a separate receiver battery and use the main battery just for the motor? The worst case scenario is that the battery is nearly empty after a climb, and there won't be enough capacity left for the rest of the flight. In good conditions, this plane can easily stay aloft for half an hour, and I don't want the receiver to shut down in the air.
As you probably know by now, I am a beginner when it comes to electrics, so any tips and advice are welcome.
I'd go for the external uBEC (Switching Power Supply Battery Elimination Circuit)
A lot of them are available. I've got 9 or 10 of the Castle Creations 10 Amp uBEC in my various models. They've all been flawless, and two of them are in 2500 watt giant scale models.
If you're flying with LiPo batteries, just be careful not to use the motor power for over 50% of the Lipo's capacity, and you'll be just fine. That 50% rule for the receiver power is one I've been following for near 50 years of flying RC models. That includes a whole bunch of sailplanes with electric power in the 1980's.
IMHO, electric launch of those sailplanes is a natural match. That gets rid of the rubber band launch parachute landing in the trees, or trying to find a big enough field for a winch launcher. (Did both of them) A properly setup electric motor launch will get your sailplane far higher in the air than either the bungee or winch launch.
One caution with electric launch though. If you can fit them in, spoilers are a wise addition to your model(s). Problem is, with those very high launch altitudes with electric launch, it can be an issue trying to get your model back on the ground in strong thermal activity. Spoilers really help in this regard.