What is the rule of thumb for final approach speed in a glider?

What is the rule of thumb for final approach speed in a glider?

• A. 80 percent of stall speed
• B. 50 percent above the glider's stall speed plus half the estimated windspeed
• C. The minimum controllable airspeed
• D. Stall speed plus 10 knots

Answer: (B)

Approach speed must stay well above stall speed to keep the glider controllable in gusts and to maintain a stable, safe path into landing. The best-remembered rule of thumb is to fly final approach at about 1.5 times the stall speed, and then add half of the estimated headwind. The 1.5× stall speed gives a solid margin above the stall so you can cope with gusts and small control inputs without stalling, while the wind correction accounts for the wind’s effect on your actual approach energy and handling near the ground. For example, if the stall speed is 28 knots and the headwind is 12 knots, you’d aim for about 1.5×28 = 42 knots plus 0.5×12 = 6 knots, totaling around 48 knots indicated airspeed. Choosing a speed at the stall or only slightly above it risks losing control in gusts or during round-out. Similarly, only stall speed plus 10 knots often isn’t enough margin in variable wind.

Approach speed must stay well above stall speed to keep the glider controllable in gusts and to maintain a stable, safe path into landing. The best-remembered rule of thumb is to fly final approach at about 1.5 times the stall speed, and then add half of the estimated headwind. The 1.5× stall speed gives a solid margin above the stall so you can cope with gusts and small control inputs without stalling, while the wind correction accounts for the wind’s effect on your actual approach energy and handling near the ground. For example, if the stall speed is 28 knots and the headwind is 12 knots, you’d aim for about 1.5×28 = 42 knots plus 0.5×12 = 6 knots, totaling around 48 knots indicated airspeed.

Choosing a speed at the stall or only slightly above it risks losing control in gusts or during round-out. Similarly, only stall speed plus 10 knots often isn’t enough margin in variable wind.