Lecture: Forces in Climbing, Descending, Turning, and Gliding

Introduction

• Objective: Explore the physics and forces in climbing, descending, turning, and gliding.
• Reference: Principles of flight episodes (Flying Physics 1 & 2).
• Baseline: Steady level flight - forces are balanced (Thrust = Drag, Lift = Weight).

Climbing

• Forces: Thrust, Drag, Lift, and Weight.
• Weight Components:
  • Down the slope: ( W \sin(\theta) )
  • Into the slope: ( W \cos(\theta) )
• Force Balance:
  • Thrust = Drag + ( W \sin(\theta) )
  • Lift = ( W \cos(\theta) )
• Implications:
  • Thrust > Drag
  • Lift < Weight

Descending

• Forces: Similar components as climb.
• Force Balance:
  • Thrust + ( W \sin(\theta) ) = Drag
  • Lift = ( W \cos(\theta) )
• Implications:
  • Drag > Thrust
  • Lift < Weight

Gliding

• Characteristics:
  • No thrust involved.
  • Glide is a descent without thrust.
• Force Balance:
  • Drag = ( W \sin(\theta) )
  • Lift = ( W \cos(\theta) )
• Angle of Glide:
  • Determined by ( \tan(\theta) = \frac{\text{Drag}}{\text{Lift}} )
  • A low drag-to-lift ratio means a shallow descent and long glide.
• Influence of Weight:
  • Does not affect the angle of glide.
  • Heavier weight increases glide speed but not the glide angle.

Turning

• Forces Involved: Lift and Weight.
• Banking: Lift acts at an angle.
  • Vertical component: ( L \cos(\theta) )
  • Horizontal component: ( L \sin(\theta) ) (used to turn).
• Force Balance:
  • Weight = ( L \cos(\theta) )
• Load Factor:
  • Defined as ( \frac{\text{Lift}}{\text{Weight}} = \frac{1}{\cos(\theta)} )
  • Need to increase lift in turns to maintain level flight.
  • Example: 60-degree bank requires doubling lift (Load factor = 2).

Conclusion

• Summary:
  • Climb: Thrust > Drag, Lift < Weight.
  • Descent: Drag > Thrust, Lift < Weight.
  • Glide: Drag = ( W \sin(\theta) ), Lift = ( W \cos(\theta) ).
  • Turn: Increase lift to balance weight in a banked position.
• Additional Resources: Principles of Flight series for detailed concepts.