Lecture Notes: Performance in Climbing, Descending, Turning, and Gliding

Introduction

• Focus on the physics and forces involved in:
  • Climbing
  • Descending
  • Turning
  • Gliding
• Review from "Principles of Flight"
• Recommended episodes for more detail: Flying Physics 1 and 2

Steady Level Flight

• Four forces in balance:
  • Thrust = Drag
  • Lift = Weight

Climbing

• Forces involved:
  • Lift, Weight, Thrust, and Drag
• Weight is broken down into components:
  • W * sin(θ): acts down the slope
  • W * cos(θ): acts into the slope
• Balance of forces:
  • Thrust = Drag + W * sin(θ)
  • Lift = W * cos(θ)
• Key Points:
  • Thrust is more than drag
  • Lift is less than weight

Descending

• Similar force breakdown as climbing:
  • Lift = W * cos(θ)
  • Thrust + W * sin(θ) = Drag
• Key Points:
  • Drag is more than thrust
  • Lift is less than weight

Gliding

• No thrust is present
• Forces:
  • Lift = W * cos(θ)
  • Drag = W * sin(θ)
• Glide angle:
  • Determined by lift and drag
  • Angle is shallow if lift-to-drag ratio is high
  • Glide speed (Vmd) is where minimum drag occurs
• Weight does not affect glide angle, just speed

Turning

• Aircraft is banked:
  • Lift acts at an angle to vertical plane
• Force components:
  • Vertical: Lift * cos(θ) = Weight
  • Horizontal: Lift * sin(θ) (causes turn)
• Increase in lift required:
  • Load Factor: Lift/Weight = 1/cos(θ)
  • Example: 60° bank requires doubling lift (load factor = 2)
• Increase lift by:
  • Increasing angle of attack

Summary

• Climb:
  • Thrust > Drag
  • Lift < Weight
• Descent:
  • Drag > Thrust
  • Lift < Weight
• Glide:
  • Focus on balance: Drag = W * sin(θ)
  • Lift = W * cos(θ)
• Turn:
  • Lift is split into components
  • Increased lift is essential to maintain level flight