Comment fonctionnent les hélicoptères - Plongée approfondie/Helicopter Physics Series - #5 Autorotation = NO PARACHUTE! - Smarter Every Day 50
Helicopter Physics Series - #5 Autorotation = NO PARACHUTE! -  Smarter Every Day 50

Helicopter Physics Series - #5 Autorotation = NO PARACHUTE! - Smarter Every Day 50

SmarterEveryDay4 min27 avr. 2012
Helicopter Physics Series - exploring how helicopters work
6 chapitres
  • Introduction to Helicopter Safety(0'000'43)
    Destin welcomes viewers back to the Smarter Every Day helicopter series and introduces the concept of parachutes used by airplane pilots for emergency situations.
    Destin and his son test a toy parachute by throwing it from a balcony, which lands in the ocean, illustrating basic parachute functionality.
    If airplanes have parachutes for safety, what happens when a helicopter loses engine power and begins to fall?
    Helicopters have a built-in safety mechanism that doesn't require jumping out, related to how the rotor system can be used to descend safely.
  • Understanding Autorotation Physics(0'431'54)
    When a helicopter loses engine power at altitude, the aircraft and its weight are suspended by the rotor system that suddenly has no power.
    • Decrease blade pitch to allow gravity to spin the rotors very fast, creating a windmill or pinwheel effect • Right before impact, increase blade pitch to convert rotor momentum into lift for deceleration
    This emergency procedure is called autorotation and has saved helicopter pilots for many years.
    Helicopter pilots have successfully executed autorotations from altitudes as high as 40,000 feet.
  • Autorotation Demonstration Setup(1'542'26)
    Carl, a helicopter pilot, is introduced to demonstrate autorotation in a real helicopter.
    Carl will take the helicopter up several hundred feet, shut off the motor completely, and fly it to the ground entirely without power using autorotation.
    Destin notes that the helicopter being used for the demonstration is expensive, and Carl confirms he understands the risk involved.
    The demonstration is about to show viewers how autorotation works in practice with a real aircraft.
  • First Autorotation: Normal Descent(2'263'02)
    Carl reaches approximately 300 feet in altitude before initiating the emergency procedure.
    Carl turns the motor off completely, and the helicopter begins descending without any engine power.
    • Carl reduces the pitch of the blades to allow them to spin • Air being forced through the rotor system by gravity spins the blades rapidly • This creates a windmill effect that keeps the blades rotating
    The helicopter descends smoothly and lands safely while remaining upright throughout the maneuver, demonstrating helicopter safety superiority over airplanes.
  • Advanced Autorotation: Inverted Flight(3'023'52)
    Carl suggests repeating the autorotation demonstration but with the helicopter inverted (upside down) to show the maneuver's advanced capability.
    • Destin initially jokes that he's not impressed, prompting Carl's challenge • Carl and Destin both confirm this is an executable maneuver • Destin humorously disclaims responsibility for the outcome
    Carl flips the helicopter upside down while it is completely unpowered and descending, demonstrating the technique's versatility.
    The helicopter successfully completes the inverted autorotation and lands safely, proving that autorotation works even in unconventional orientations.
  • Conclusion and Series Information(3'524'40)
    Helicopters are significantly safer than initially thought due to their built-in autorotation capability, which functions as an automatic safety system.
    This episode is part of a larger series about helicopter physics and control systems that Destin and Carl are producing together.
    • Viewers are encouraged to watch the complete helicopter control series for more information • Carl's contact information has been included in the video description • Viewers are asked to subscribe to the channel
    Captions provided by Andrew Jackson, with invitation for multilingual caption contributions.