Janus B spins into trees from a steep, slow turn at the ridge
A two-seat Janus B ridge-soaring the Schänerberg stalled out of a steep, slow turn ~100 m up, spun into trees, and was destroyed; both occupants were seriously injured. In weak blue thermals he had gained only 400 m in half an hour and worked the slope low, still at +8° camber flap. Turning back toward the ridge at ~50° bank and only 90 km/h, he was below the stall speed for that flap and bank, and it departed. With little time on type, he had not allowed for how far the flap and bank raised the stall speed — standard practice is flap 0 on ridge lift. Cause: below minimum speed, with too little allowance for the higher turning speed.
- Ridge thermaling flight: After aerotow release at about 1700 m, the pilot flew weak to moderate thermals and then began ridge-soaring along the Schänerberg with flaps set to +8°.
- Low climb, low margin: In weak lift the pilot needed about 30 minutes to gain only 400 m, continuing to operate close to the terrain with limited altitude margin.
- High bank near terrain: At about 1300 m MSL and roughly 100 m above ground, the pilot flew steep ridge turns with 45–50° bank despite the weak updraft conditions.
- Flap setting +8°: The glider remained in +8° flap setting, increasing stall speed in banked turns, which the pilot did not adequately account for.
- Right turn at low speed: While turning right back toward the slope with about 50° bank at roughly 90 km/h, the glider’s airspeed was below the required minimum for that configuration and bank angle.
- Stall and spin entry: The glider stalled and entered a spin at approximately 100 m above ground, leaving insufficient height for recovery.
- Crash - serious injury: In a right-hand spin the glider struck 20 m high trees on the steep Schänerberg slope and was destroyed, seriously injuring both occupants.