1. SPEED TO FLY THEORY WHEN TO USE IT AND WHEN NOT TO

2. Basic Glider Performance. Minimum Sink –The speed at which the glider’s sinking speed is at its lowest. Best Glide –The ratio of forward speed to sinking speed. –As the gliders speed increases it’s sink rate increases –This can be plotted on a polar curve.

3. The Polar Curve

4. Polar Curve Best Glide Minimum sink Minimum sinking speedBest glide speed AIRSPEED / SINK RATE = BEST GLIDE ANGLE 53 / 1.2 = 40.8

5. Glides in a sinking airmass

6. Graphical representation To represent 2kts of sink the polar can be moved down the graph by 2kts 2kts

7. OR The 0,0 point can be moved UP 2kts New 0,0 Note the new speed to fly of 71 kts

8. All speeds to fly for various sink conditions can be calculated and plotted onto a new graph Mc Cready Graph

9. Mc Cready Ring These values can be plotted on a ring that fits round the vario When constructing a Mc Cready ring include the gliders sink rate