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

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


Hey it’s me Destin.Welcome back to Smarter Every Day.
We’re right in the middle of a series on helicopters and we’re gonna talk to you about.. What is this called?
(son) Parachute. A parachute.
So in airplanes, the pilot can have a parachute so if anything
goes south he can jump out and he can parachute to safety.
Do you want to test the parachute real quick? (son) Yeah I’ll do it.
OK we’re gonna use the parachute off the balcony here. Check this out. Daddy’s gonna throw it. You ready? Parachute man… in the ocean. 1…2…3… Oh man! [laugh] We just gave the parachute man to our neighbours. So think about this.
Let’s say we’re in a helicopter and we’re up high and all of a sudden we run
into trouble when we run out of engine power and we start to fall.
So we’ve got this weight and it’s suspended by this rotor system.
Now if we’re smart about it we can change the pitch on our blades to
spin up our rotors really really fast. And then we have kind of like a
pinwheel or a windmill effect. And if we’re really smart, right at the last minute,
right before we hit the ground, we can change the pitch on those
blades to provide lift. So we’re back driving our rotors and then right at the last
minute we’re using them to decelerate, right before we hit the ground.
This is a manouver called autorotation, and this has kept helicopter pilots alive
for many many years. In fact, they’ve even done autorotations from 40,000 feet. So a helicopter basically has a built-in parachute.
But with a helicopter you’ve got this rotating disc right in front of you.
So my question is, what happens if you lose power at altitude. So this battery he just put in, what if it dies.
So what happens Carl? (Carl) If you lose power in a helicopter you can autorotate.
Alright. So Carl’s gonna demonstrate autorotation and
we’ll get an idea for what happens. You’re getting Smarter Every Day. Alright so what exactly are we about to do here? (Carl) We’re gonna demonstrate autorotations.
I’m gonna take you up a couple of hundred feet up in the air shut the motor off, and fly it all the way
to the ground without power. (Destin) Sounds like a genius idea to me.
(Carl) [laughs] Let’s do it. (Destin) You know… This is expensive right?
(Carl) Yeah [ rotor noise ] Alright so where you at? How high? (Carl) Aah this is probably about 300 feet. Three and I’m gonna turn the motor off right now, and we’re coming in without power.
(Destin) On a very expensive helicopter.
(Carl) Oh yeah.
(Destin) So there’s no power right now. (Carl) No power at all. (Destin) So why did that happen? What did you just do?
(Carl) We’re turning the pitch of the blades down, and as the helicopter is falling down, the air being forced through by gravity spins the blades.
(Destin) So it’s like a windmill?
(Carl) It’s like a windmill.
(Destin) So helicopters are a whole lot safer than I thought. I’m gonna be honest with you I’m not very impressed though cause it was right side up the whole time.
[laughs] (Carl) Let’s do it upside down.
(Destin) W..w..wait dude. I’m joking dude. (Carl) Aah. Let’s do it!
(Destin) He can do it.
(Carl) Let’s do it! I am not responsible for what’s about to happen. [rotor sounds] You don’t have to do it if you don’t want to.
(Carl) [laugh] (Destin) Are you upside down already?
(Carl) Oh yeah. (Carl) Here we go. We’re gonna flip upside down. (Destin) So you have an unpowered..
(Carl) Power is off
(Destin) helicoper upside down.
(Carl) Correct. (Destin) This makes perfect sense. Holy cow. [laughs] (Carl) There we go.
(Destin) That is messed up man. Alright so helicopters are a whole lot safer than I thought, and if you want to see more about how they work look at this video series that we’re making, how to control helicopters. This is Carl. I put his info in the description. Please subscribe. Later. Where’s my thinking hat? I need my thinking hat.
[laughs] [ Captions by Andrew Jackson ] Captioning in different languages welcome.
Please contact Destin if you can help.

Eugene Islam

100 thoughts on “Helicopter Physics Series – #5 Autorotation = NO PARACHUTE! – Smarter Every Day 50

  1. I always thought auto rotation was because of the momentum in a rotating heavy chunk inside the helicopter built up during start. I mean why does it take so long for a helicopter to start and I though it stores it as rotation energy. So if the engine stops the rotation energy is there to save the day. That was what I thought but watching this video I learned that it wasn't the case. So that leaves me with a question. Why does it take so long time to start up a helicopter?

  2. Hmm, russian military helicopters do have a parachute. They just shoot off the rotors and then launch themselves out(probably in case of a serious error, like no control of the rotors or something)

  3. This is the best playlist I have ever seen. I saw it again after so much time I have so many good memories of when I was learning it. BTW watching this again after so much time makes u put every knowledge in order and clarifying concepts.

  4. Safe if you have altitude !! for auto-rotation or  momentum plus a little altitude ) every  helicopter pilot has to do this in his training .

  5. I study aerospace engineering and I remember when I first learned these principles was like "Holy S#@t! that's going to be my field of expertise", much interesting than a cylinder with 2 angular beams that runs through the air

  6. Again, I've gotta say that autorotation was well known before Sikorsky. De la Cierva had already developed the autogyro, to avoid airplanes' stall at low speed.
    Actually autorotation has a deeper and more complex approach, that makes the autogyro able to get lift, even though air goes from below the blades to above them.

  7. How does the tail rotor keep spinning when the helicopter drops though? Shouldn't the helicopter loose control because of that?

  8. This goddamn dude puts a smile on my face just watching him fly like that as naturally as most people walk… =)

  9. Your backwards bike video made the rounds at my work and now I can't stop watching your videos. Keep up the good work! These are great.

  10. you can learn how to do auto-rotation if you play ArmA 2 or 3 and find the emergency landing tutorial for helicopters
    (ArmA 2 has a 3-in-one thing for helicopters, the tutorial in ArmA 3 is in the VR training)

  11. I had a professor who was a helicopter test pilot in the 60s and 70s. According to him, the blades on a huey were so heavy (thus having lots of momentum) that you could autorotate to the ground and then pick it back up, turn it 180 degrees, and land again. All with no power.

  12. This guy is the boss…inverted autorotation and flip… impressive.
    However, real choppers don't autorotate that well, unless they are really light.
    For instance, you can try to land a Black Hawk in autorotation, but it's a heavy chopper, too heavy, chances are that you'll break your legs in the impact…
    Sure, autorotation will prevent the Black Hawk from being destroyed, but it won't make it land as gently as this one…

  13. Yes it works, but every helicopter has a death zone. It is the zone below a certain hight that does not allow you to perform the autorotate. In other words you don't have enough hight to fall far enough so that the blades can spin fast enough to perform it. Most wild life catchers, rescue teams, firefighters and farmers fly in this zone.

  14. I found this channel today, and not liking it much. You don't explain things. Saw all the heli playlist till this one and learned so little. In this one, like in the majority, you said that the autorotation is like a parachute, made the guy do it with his heli and boom, we all suddenly know what it is, and how it works.

  15. So it looks like the tail rotor is actually connected to the main rotor, meaning that you still have power available to the tail rotor in the event of engine failure. Neat.

  16. i'm guessing, you need a certain side blade to do auto-rotation? it'll be awesome on multicopters but we have to be sticking to parachutes on those for now.

  17. i knew that this is possible because I played that thing that you shoot into the air and it comes falling down rather slow but I forgotten the fact that helicopters has swashplates so basically pilots can still lift the helicopter at the last sec so that the helicopter could land at a safe speed despite having no engine on. I thought it is going to crash land lol. Swashplate, you magical thing

  18. THATS GOOD STUFF .I VE BEEN FLYINH HELIS RC HELIS FOR A NUMBER OF YEARS AND I THOUGHT I UNDERSTOOD WHY I COULD MAKE THEM DO SOME OF THOSE TRICKS .NAH ! NOW I KNOW GOOD STUFF. THANKS I ENJOYED I SAT WATCHED THE WHOLE SERIS

  19. I'm told that autorotation in a full-size helicopter is extremely difficult and terrifying. This guy absolutely has skills, but he doesn't die when he gets it wrong.

  20. This just made me realize how those "helicopter" seed pods from trees work when they slowly spin down to the ground and why they do that (so as not the damage the seed on the way down).

  21. So, in a full size helicopter the rotors are pushed by rods and manual control by the pilot (who is inside). However, in an R/C helicopter, do you have a separate battery for the receiver and the servos to maintain control if you lose main battery power?

  22. Also, there is a helicopter model that has a parachute ejection system for the pilot (Russian KA-50)

  23. Question: why does the upwards rushing air (while the chopper is falling) rotate the rotors? To do so (via the pinwheel or windmill effect), the rotors would have to be in negative collective pitch for the duration of the descent and then immediately be switched to full positive collective right before landing. However, if I come correct, full scale helis just go to 0 collective (NOT negative) and flare full collective right before touchdown…i.e. no negative collective. Meaning that autorotation only uses rotor momentum and DOESN'T actually use rushing air to windmill the rotors. Can anyone validate this?

  24. My brother fell out of the sky in a disabled helicopter. The pilot autorotated. They landed hard, but no one was killed.

  25. As a pilot myself thats pretty good and i can def. do those manuvers, He takes off and with a crazy style and half piro flips just to turn upside down in the other video XDXDX

  26. Slightly confused… Does this happen when the pilot loses power for the main motor, but retains control of the squashplate? So they could then reverse the pitch of the blades while in free fall to gain rotation speed, and then reverse again close to the ground to generate thrust?

  27. Probably a little late to mention but the 'Fatherhood failure' moment with the toy parachute was caused by slope lift created by air (wind) blowing at and over the building. What he did was actually a very short slope soaring flight 🙂
    Google 'slope soaring' for more info, and then try 'Dynamic Slope Soaring' to really get blown away so to speak…

  28. But do you still need your counter torque when you fly without the main cause isn’t the helicopter going to spin out of control

  29. This video taught me something I just couldt imagine before. This video is nothing without watching the previous 4 before. I finally understood how helicopters are so safe. There are gliding seeds in trees here in my town and they are like helicopter blades, you can see it from time to time and this video reminded me of that. This is great.

  30. What actually happens with the collective pitch in all fases of the autorotation? Do the pilot put it in a position to the chopper go down faster in the moment the engine is shutted off or in a neutral position?

  31. Yeah not “air forced through by gravity”. Auto gyros existed before helicopters, they always new that helicopters could autorotate.

  32. Destin, not sure but I think you should get some slow motion video of this helicopter in action to explain physics. Super life like and skillful flier means for a great video. Hope you see this and take it into consideration! Love the YouTube Channel! A.Reese

  33. A similar concept is actually used in a certain type of aircraft too! Autogyros used an unpowered helicopter blade in place of wings for lift generation, and a typical propeller or jet to provide forward power.

  34. That guy has got some mad Radio Controlled Helicopter flying skills!! I flew Hueys and OH-58s in the US Army and I can never fly RC aircraft that well. I'm more of a seat-of-my-pants flyer.

  35. He asked what If that battery dies? How would you control it to autorotation if you can't communicate with it via radio? Just joking!!! 😂

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