midtoad's blog

Using a PDA in a glider

I'm now setting up a Palm TX to act as a flight computer for sailplane flying, using a Wintec WBT-201 Bluetooth GPS for positional data, and logging, and SoarPilot as the navigational software.

SoarPilot can act as a final glide computer, telling whether you can make it to goal or not, and if so, at what speed you should fly. But even en-route, it can also tell you what speed to fly between thermals, while taking into account your glider's performance polar curve, and the expected strength of the thermals (McCready ring setting). SoarPilot also has a moving-map display that will show you where you are in relation to your waypoints, and to designated airspace that you may need to avoid. You can define a task and it will help guide you around the course. If you load in terrain elevation data, it will even tell you what your ground clearance is.

The only hitch in using this software, and my hardware, is the energy consumption. With Bluetooth turned on, my Palm will run down its batteries in under 5 hours. So I picked up a sealed 2.2 Ah lead-acid battery (about the thickness of a VCR tape, though not as tall), and attached a dual cigarette-lighter plug to it that I bought at Canadian Tire. From there, I'll power my Palm with a car charger, and I'll power the GPS with a car USB cable.

In order to manage some of the data I needed, I got a copy of SoaringDotNet. I used its airspace editor (and a copy of Transport Canada's Designated Airspace Handbook) to define the airspace I'll need to avoid.

I've got everything loaded up now on the Palm. Now it's time to go for a flight and test it all out (I've already been testing it while driving around in my car).

Here are some files that may be useful: