Fellow rotorheads, let's talk autorotations. We all train for them, but let's be honest - even seasoned pilots can struggle with that perfect touchdown. The culprit? Pulling the collective too early. This mistake can be especially confusing because it can feel similar to a maneuver you might use in a different situation (a quick stop)
Now, I hear you thinking, "But isn't a quick collective pull what we do for a quick stop?" You're right. In a quick stop, raising the collective early helps arrest the descent rate. But in an autorotation, with the engine out of the picture, things change. Here's why:
Autorotation is All About Airspeed: Unlike a powered landing, where the engine provides lift, an autorotation relies on the airflow through the rotor blades for lift and control. Raising the collective too early increases the pitch of the blades, increasing the amount of air they bite and, consequently, the lift they generate. This translates to a slower descent rate, but reducing your rotor rpm.
The Magic of 5 Feet: Here's the golden rule: Delay that collective pull until you're about 5 feet from the ground. This allows the rotor blades to maintain their optimal pitch for maximum lift generation during the crucial final moments.
Flaring High vs. Low: Flaring too low is definitely risky, potentially clipping the tail boom stay and having to pull the collective early.
Energy Management: A higher flare allows you to bleed off some of the helicopter's forward airspeed. This translates to a gentler touchdown.
Time for Correction: A higher flare buys you precious seconds to assess the situation and make minor adjustments to the collective if needed.
Prioritize a Smooth Touchdown: While a tail strike is a serious concern, a hard landing due to an early flare can also damage the helicopter.
Remember: A slightly high flare with a delayed collective pull allows for a smoother, safer touchdown in an autorotation.
Conclusion
Mastering the autorotation flare takes practice and a shift in mindset from powered landings. Train in simulators and with experienced instructors to refine your technique. Remember, a smooth touchdown is always better than a risky one.
So next time you practice autorotations, don't fall into the trap of replicating a quick stop maneuver. Focus on delaying the collective pull until you've pushed forward on the cyclic and leveled the helicopter, then at around 5 feet, pull the collective to prioritize a smooth touchdown.
Happy flying!
PS: Always follow the instructions in your helicopter manual.