Helicopter Lessons: Understanding Mushing

Introduction

• Topic: Mushing in helicopters
• Relevance: Most prevalent in army helicopters, especially attack and recon types; can also occur in civilian helicopters
• Definition: A temporary stall condition occurring at high airspeeds during rapid aft cyclic application

Key Concepts

• Stalling: Occurs in both planes and helicopters when aggressively recovering from a dive
• Critical Angle: The angle at which the resultant relative wind impacts the airfoil to produce lift
• Resultant Relative Wind: Needs to impact within the positive lift region of the airfoil for effective lift
• Airfoil Regions:
  • Positive lift region
  • Positive stall region
  • Negative lift region
  • Negative stall region
  • Reverse flow region

Dive and Recovery

• Dive Profile Setup:
  • Aircraft traveling straight, resultant wind inside positive lift region
  • During dive, resultant wind still within positive lift region
• Recovery from Dive:
  • Aggressive aft cyclic can lead to a mushing state
  • Aircraft's momentum continues downward, resulting in ineffective lift

Effects of Mushing

• Control Feedback: Aircraft continues descent despite pitched-up attitude
• Historical Context: Similar issues faced by WWII fighter pilots during strafing runs
• Controlled Flight Into Terrain (CFIT): FAA term for aircraft striking ground without mechanical failure

Recovering from Mushing

• Common Mistake: Applying more aft cyclic, worsening the stall
• Correct Method:
  • Apply forward cyclic to shift resultant wind back to a useful angle
  • Slowly reapply aft cyclic to safely recover

Prevention Strategies

• Avoidance:
  • Use slower, more progressive aft cyclic during dive recovery
  • Plan for adequate altitude for maneuver recovery
  • Be aware of increased recovery altitude and time at higher altitudes or airspeeds

Conclusion

• Summary: Mushing is a temporary stall mainly during aggressive aft cyclic in dives
• Further Resources: For deeper understanding, refer to the "Dissimetry of Lift Expanded" video

Closing Remarks

• Instructor: Jacob
• Channel: Helicopter Lessons in 10 Minutes or Less
• Call to Action: Like, subscribe, and comment for more informative videos
• Safety Reminder: Safe flying!