I was wondering if there is a device that i can put in my glider that will signal me if it is in lift.

From : Don Stackhouse

There is such a device. It's called a "thermal sniffer". It consists of a sensor plus a small radio that goes in the plane, and a receiving unit on the ground. The sound you hear from the receiving unit changes with any change in the rate of climb or descent, just like the audio variometers common in full-scale sailplanes.

Unfortunately, they're usually rather expensive, hard to find, bulky enough that they really don't fit in anything smaller than an open class model, and they usually transmit on frequencies that require a Ham license. The last production one I'm aware of was made by Multiplex in Germany. It was a very nice system, and ran on 27mhz (no Ham license required!) but they recently discontinued it.

Of course one of the best thermal sniffers available is a good set of well-trained eyes. About the only applications where electronic thermalling aids (thermal sniffers) are commonly used is for cross-country models. These typically fly so high and so far away that it can be tough to tell when they're in lift. For just about any other type of thermal flying you can learn to see when the model is climbing. With a little practice you'll find that for most applications a thermal sniffer is just unnecessary extra cost and weight. One of the best ways to learn thermalling is with a hand-launch model. They fly so close to you that it's easy to see if they're going up or down. Once you learn the techniques close-in with HLG's, it's not too hard to learn to apply them farther away for larger classes of sailplanes. Just as with most things in life, good things come to those who practice!

Don Stackhouse
DJ Aerotech