Lecture Notes: Designing a High-Performance Toy Helicopter

Introduction

• Inspired by childhood helicopter toys
• Objective: Make a high-performance version
• Encountered design flaws during development

Basic Mechanics of Toy Helicopters

• Spin between hands to store kinetic energy
• Generates thrust by blowing air downwards
• Spin faster = higher altitude
  • Limited by supersonic speed, which creates drag

Design Enhancements

• Flywheel Concept:
  • Slower propeller with fast-spinning flywheel
  • Reduces air drag, stores more energy
  • Simulation: Flywheel-enhanced version goes five times higher

Major Design Challenge: Safe Descent

• Initial Plan: Parachute Deployment
  • Risk of entanglement in spinning blades
• Alternative Plan: Auto-rotation
  • Energy refilled during descent
  • Blades reverse angle for controlled landing

Gyroscopic Precession Issue

• Flywheel acts like a gyroscope, resisting orientation change
• Causes unintended flipping
• Solution: Twin flywheels spinning in opposite directions to balance precession

Connection between Flywheels and Propeller

• Use of bevel gears
  • Converts perpendicular motion
  • Custom-made gears for light weight

Manufacturing Process

• Use of CNC machines and water jets
• Creation of custom gears and components

Oversight and Problem-Solving

• Gyroscope Effect Oversight:
  • Twin flywheels cancel out each other's gyroscopic effect
  • Results in backward spin during flight
• Attempted Solution:
  • Add control surfaces for counter-torque
  • Larger wings for better air leverage

Testing Phase

• Initial test had friction and power issues
• Solutions:
  • Sealed flywheels with heat shrink to reduce air drag
  • Increased motor power

Final Tests and Results

• Training gear used for safety
• Helicopter struggled with lift and stability
• Flywheel air drag resolved late into testing

Conclusion and Future Directions

• Helicopter not yet functional
• Plans for redesign and further testing in Part 2

Personal Insights

• Importance of routine and learning
  • Exercise and self-education
• Sponsored by Brilliant for learning technical subjects

Final Test

• Attempted launch with family
• Helicopter took off but crashed
• High hopes for future adjustments