When grams add up: hike-and-fly with mini BT

A typical lightweight hike-and-fly setup looks like this:

• Wing: 2.5–3 kg
• Harness: 600–900 g
• Reserve: 1.0–1.4 kg
• Helmet: 200–350 g
• Phone + power bank: 300–500 g
• Instruments: ???

If your variometer is 80 g, that’s an extra apple in the bag. If it’s 9 g, it’s the weight of a single AA cell — gone, lost in the rounding.

Where the gram count helps

Long approaches. A 2-hour up-track is where the difference between “my pack is heavy” and “my pack feels fine” gets decided. The vario isn’t where you save the most grams, but it’s the easiest one to fix: a dedicated flight computer at 80–200 g, replaced by a 9-g sensor that pairs with your phone, removes a whole device.

Travel. Carry-on weight limits matter on every European budget airline. Each piece of redundant electronics is room you don’t have for batteries, spare straps, or a second pair of gloves.

Cold flying. A lithium primary cell (CR2032) doesn’t lose capacity at –10 °C the way a small Li-Po pack does. The mini BT keeps beeping above the treeline when other devices have folded.

Where it doesn’t

Comp days with split sectors. If you fly long racing tasks, you probably still want a dedicated flight computer with its own screen for redundancy. The mini BT in that case is a second pressure sensor — a sanity check on the main instrument — and a fall-back if the main vario freezes mid-task.

Wing-mounting. A 9-g device hanging off your front-mount disappears, but direct airflow on the sensor will overwhelm the climb signal. Tuck it in the cockpit pouch or behind a flap of fabric. Sheltered placement matters more than mounting style.

The packing trick

Slide the mini BT into the same pocket as your phone. Velcro it to the phone case if you’re nervous about losing it. The BLE range is comfortably more than the 30 cm between your pocket and your face — there’s no positioning to get wrong.

When you land, drop it back in the pocket. There’s nothing to plug in, no charging cradle to pack, no port that fills with dust.