4c - Minimum Sink
Required for Solo: 61.87(i)(8)
Required for Private: PTS V(A)
Lesson Objective
The lesson will learn the minimum sink speeds, how they relate to bank angle, and the importance of using the correct minimum sink speeds.
Regulatory Requirement
- Pre-Solo: 14 CFR §61.87(i)(8)
- Private Pilot Candidate: PTS V(A)
Content
- Minimum sink speed for each club aircraft
- Minimum sink speed for differing bank angles
- Glide ratio at minimum sink. Compare with glide ratio at Max L/D
- Minimum sink speed at the minimum pilot weight (solo) and at the glider's maximum gross weight
Completion Standards
The student must be able to perform:
- Straight and Level flight at minimum sink speed
- 30° bank turns at minimum sink speed.
- 45° bank turns at minimum sink speed.
The student must be able to explain:
- The effect of bank angle to minimum sink speed.
- The effect of aircraft loading to minimum sink speed.
Prerequisite Study
- Glider Flying Handbook (2024), Chapter 5, "Glider Polars" Page 5-10
- Glider Flying Handbook (2024), Chapter 7, "Thermalling Speed" Page 10-7
- SSC Cockpit Cards