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18.02.2011, 07:54
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| | | Re: Helicopter crash - 6 tourists injured
If Longbyt might let me express an opinion on this one  , gut feeling says it was either tail clip or tail rotor failure from the way they went in sideways
And they're all very lucky...
...in a helicopter? When there's a whole stack of lifts? Burm...? Gener...ouch? I mentioned it once but I think I got away with it...
Expect very little news update from this one
Last edited by weejeem; 18.02.2011 at 08:08.
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18.02.2011, 08:14
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | | | | | | It appears your suspicions about passenger number inaccuracies are correct.
From what I've read, there was the pilot, a mountain guide, ski teacher and three skiers (customers), giving total of six.
The following reports that: " .... two have slight injuries and four are in good condition." http://genevalunch.com/blog/2011/02/...lerets-update/
The term "lucky buggers" comes to mind, having seen the photo(s).
When helicopters stop flying, they don't glide, but just drop; and don't bounce very well, just crumple.
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18.02.2011, 08:24
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| | | Re: Helicopter crash - 6 tourists injured
There is a way to do a controlled emergency descent so that a helicopter does not fall out of the sky if there is a problem. A pilot told me about it when flying in his helicopter, don't know all the ins & outs of what happens since I can't fly one myself. | Quote: | |  | | | When helicopters stop flying, they don't glide, but just drop; and don't bounce very well, just crumple. | | | | | | 
18.02.2011, 08:50
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | There is a way to do a controlled emergency descent so that a helicopter does not fall out of the sky if there is a problem. A pilot told me about it when flying in his helicopter, don't know all the ins & outs of what happens since I can't fly one myself. | | | | | You have to drop the collective - but that's only "works" if the engine fails. From my understanding, I don't know how "controlled" , this would be - I just think you hit the ground less hard, with the dirty side down. If, as previously suggested (speculation?), it was a tail or tail rotor problem, then this would cause the craft to spin on its central axis, with nothing the pilot could do, to regain control.
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18.02.2011, 09:14
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| | | Re: Helicopter crash - 6 tourists injured
Copters can glide, its called autogyro, but they have to be moving forward, if they where stationary in the air then yes they could pretty much just drop, really depends what the issue was
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18.02.2011, 09:24
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| | | Re: Helicopter crash - 6 tourists injured
anyway... lucky guys...
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18.02.2011, 10:31
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | Copters can glide, its called autogyro, but they have to be moving forward, if they where stationary in the air then yes they could pretty much just drop, really depends what the issue was | | | | | Sorry this is OT a bit.
Whilst it is true that a helicopter pilot can set his "rotary wing" to the best angle of attack to maintain maximum lift through forward flight, to make a controlled decent without power, following an engine failure (similar to fixed wing procedure), the actual term is autorotation. http://en.wikipedia.org/wiki/Autorot...8helicopter%29
Autogyro is this:
This not meant in a pedantic, vindictive way.
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18.02.2011, 10:45
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | Sorry this is OT a bit.
Whilst it is true that a helicopter pilot can set his "rotary wing" to the best angle of attack to maintain maximum lift through forward flight, to make a controlled decent without power, following an engine failure (similar to fixed wing procedure), the actual term is autorotation. http://en.wikipedia.org/wiki/Autorot...8helicopter%29
Autogyro is this: Attachment 23751
This not meant in a pedantic, vindictive way. | | | | |
lol lack of caffeine this morning, my copter lessons where a very long time ago now | 
18.02.2011, 11:01
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| | | Re: Helicopter crash - 6 tourists injured
As a PPL Helicopter pilot myself I can tell you that Helicopters can glide very well under no power, it is call auto-rotation. It is one of the first things trainee helicopter pilots learn as it can save your life (and any passengers). You need forward momentum to flare the Helicopter before gently landing on the ground, and if done properly it can be done without any issues (or damage to the craft). | Quote: | |  | | | Copters can glide, its called autogyro, but they have to be moving forward, if they where stationary in the air then yes they could pretty much just drop, really depends what the issue was | | | | | | | The following 4 users would like to thank WelshBoyo for this useful post: | | 
18.02.2011, 11:09
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | You have to drop the collective - but that's only "works" if the engine fails. From my understanding, I don't know how "controlled" , this would be - I just think you hit the ground less hard, with the dirty side down. If, as previously suggested (speculation?), it was a tail or tail rotor problem, then this would cause the craft to spin on its central axis, with nothing the pilot could do, to regain control. | | | | | Autorotation works with a failed tail rotor too. Most of the work the tail rotor does is counteracting the torque of the engine on the main rotor. If the tail rotor goes out, you can cut power to the engine and autorotate. You do need a certain amount of forward momentum and/or altitude to start with.
(Not actually a helicopter pilot -- but I flew R/C helis many years ago, does that count?)
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18.02.2011, 11:40
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | Autorotation works with a failed tail rotor too. Most of the work the tail rotor does is counteracting the torque of the engine on the main rotor. If the tail rotor goes out, you can cut power to the engine and autorotate. You do need a certain amount of forward momentum and/or altitude to start with.
(Not actually a helicopter pilot -- but I flew R/C helis many years ago, does that count?) | | | | | The tail rotor is counteracting the torque effect of the main rotor whether there is engine power or not. Turning the engine off is not recommended if you still have a functioning engine (e.g. no fire etc). Entering Auto-Rotation would be recommended for most circumstances as it is the safest/quickest way to land, but it is going to help having that engine running for a smoother landing (to pull power).
Losing the tail rotor is going to be one hell of a ride, as the cockpit is going to be spinning the opposite direction to the main rotor blade - not much fun I bet, but still possible to land without injury (I have met pilots who have).
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18.02.2011, 12:32
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | (Not actually a helicopter pilot -- but I flew R/C helis many years ago, does that count?) | | | | | So did I, and auto-rotations were something my instructor made me practice at the end of each flight. Engine failures or running out of fuel is easy to tackle, on my flying field the most common causes of RC heli accidents were momentary losses in concentration leading to disorientation and vibration related causes (e.g. servo or power wires shaking loose, unbalanced rotor blades leading to linkages failing etc..)
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18.02.2011, 13:40
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | Autorotation works with a failed tail rotor too. Most of the work the tail rotor does is counteracting the torque of the engine on the main rotor. If the tail rotor goes out, you can cut power to the engine and autorotate. You do need a certain amount of forward momentum and/or altitude to start with. | | | | | This is correct. The following quote from Wiki (not always gospel in itself): ".... but autorotations can also be performed in the event of a complete tail rotor failure or following loss of tail-rotor effectiveness[4], since there is virtually no torque produced in an autorotation."
from the following link: http://en.wikipedia.org/wiki/Autorot...8helicopter%29 | Quote: | |  | | | The tail rotor is counteracting the torque effect of the main rotor whether there is engine power or not. | | | | | I don't wish to tread on toes (especially as my practical experience doesn't extend to rotary wing aircraft), but I think that this, unfortunately, is not an accurate assessment.
As in the above quote, it is the airframe that is trying to counter the rotation of the engine **, which is fixed to it. Hence the requirement for the tail rotor to provide counter force against the torque of the engine **. This is true of s.e.l. fixed wing - when full throttle (for take off) is applied, then more right rudder is required to counter the torque effect of the engine **. [The same is even true of the boxer engine on my BMW motorbike - a handfull of throttle, when statioary, makes it want to lean to side]. ** the rotation of the drive shaft from the engine.
As soon as there is no power to the rotor then there is no airframe counter-rotation (which is fortunate, as there is also no power to the tail rotor with an engine out). When the rotor is "free-wheeling" through forward motion alone, it is still providing lift to prevent the helicopter falling directly to the ground, but without motorised power, can't do anything else but head groundwards.
If a tail rotor was always needed to counter the rotation of the main rotor (and not engine torque), then an autogyro would also a require a tail rotor - which it doesn't. It has a free turning, unpowered main rotor to provide lift (i.e. rotary wing), which only rotates through forward motion provided by a "normal" engine-powered propeller, working in the horizontal plain.
In the specific, unfortunate incident of this thread, I could suspect that whatever went wrong, happened within quite close proximity to the terrain, judging by the fact that the helicopter was relatively in tact, and all occupants appeared to have survived, which would have given the pilot little or no time to react (speculation).
Last edited by TiMow; 18.02.2011 at 14:08.
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18.02.2011, 14:05
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | As soon as there is no power to the rotor then there is no airframe counter-rotation (which is fortunate, as there is also no power to the tail rotor with an engine out). | | | | | The tail rotor is connected to the main rotor via drive shaft(s) and gearboxes, so even with no engine power the tail rotor will still spin depending on the main rotor speed. | Quote: | |  | | | If a tail rotor was always needed to counter the rotation of the main rotor (and not engine torque), then an autogyro would also a require a tail rotor - which it doesn't. | | | | | I would agree with you there, I also thought the rear wing (like on a plane) was also there to aid with counteracting the engine torque.
I like James May's (Top Gears) quote:-
A helicopter doesn't really fly at all, as far as I can make out. It screams and bawls like a spoilt brat until physics eventually gives in and says, "Oh, all right, all right, off you go then."
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18.02.2011, 14:19
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| | | Re: Helicopter crash - 6 tourists injured
and of course you have copters that have no tail rotor now
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18.02.2011, 14:36
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | The tail rotor is connected to the main rotor via drive shaft(s) and gearboxes, so even with no engine power the tail rotor will still spin depending on the main rotor speed. | | | | | Thanks for clearing that up - I was previously of the opinion they were independent of each other, both deriving their rotation separately from the engine. | Quote: | |  | | | I would agree with you there, I also thought the rear wing (like on a plane) was also there to aid with counteracting the engine torque. | | | | | As far as I know it's purpose is just the same as tail fin and rudder assembly on a fixed wing aircraft - to provide stability and ensure turns are coordinated.
[Technically a rudder isn't required to make an aircraft turn - this is done with the ailerons. All a rudder does is to keep the turn coordinated, so in the event of a stall, whilst turning the chances of entering a spin are significantly reduced. A plane will only spin, if stalled in an uncoordinated configuration. However the rudder is needed for ground motion/taxiing, and to counter engine torque effect during take off (and flight)].
Possibly with an autogyro, the use and need for a rudder for turns maybe more than with a fixed wing.
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18.02.2011, 14:45
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | and of course you have copters that have no tail rotor now | | | | |
The caption from this pic. reads:
"It uses the flow of fan-driven low pressure air through two tail boom ... "
.... so it effectively serves the same function of providing counter-thrust, against torque effect rotation. | 
18.02.2011, 15:01
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| | | Re: Helicopter crash - 6 tourists injured
Don't forget coaxial rotors:- | 
18.02.2011, 15:27
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| | | Re: Helicopter crash - 6 tourists injured | Quote: | |  | | | ... Turning the engine off is not recommended if you still have a functioning engine (e.g. no fire etc). Entering Auto-Rotation would be recommended for most circumstances as it is the safest/quickest way to land, but it is going to help having that engine running for a smoother landing (to pull power). ... | | | | | Agreed -- poor word choice on my part. One would reduce power and enter auto-rotation; turning the engine off entirely really takes away all your options, doesn't it?
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