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what are tethering head helicopters

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what are tethering head helicopters

Old 18th Mar 2015, 04:35
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what are tethering head helicopters

If anybody cud explain it in simple terms
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Old 18th Mar 2015, 04:51
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Link with pics

Here you go:

Helicopter Aviation
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Old 18th Mar 2015, 06:14
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Hmm. The very first words.....

"A semi-rigid main rotor is always a 2 bladed rotor system"

The head on the AS 350/355 is semi-rigid, if you read their training material. As the star is rigid drag-wise, it fits the definition. (To the original poster - that head supports three rotor blades.)

Given that it has elastomerics, I always thought that sem-articulated would have been a better term

Phil
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Old 18th Mar 2015, 07:44
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The Lynx, BO105 series etc all have four main rotor blades, too. Both are semi-rigid systems.
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Old 18th Mar 2015, 08:25
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What is a tethered head? Only references I can find are to RC models.
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Old 18th Mar 2015, 08:45
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A search for teetering rotor head gives you more results

This link Helicopter Aviation from above really explains the basic concept.

And this post from Nick Lappos http://www.pprune.org/rotorheads/675...tml#post639459 and the thread around it is more into detail. What a coincidence it refers to the same link from above almost 13 years ago.
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Old 18th Mar 2015, 09:08
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Praf: no such thing. Must be a radio controlled thang...............
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Old 18th Mar 2015, 10:54
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@shy the BO105 has a rigid rotorhead.
All the blade movement comes from a softer part in the blade base that allows lead and lag movement.
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Old 18th Mar 2015, 11:07
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@spencer: not all blade movement comes from the blade flex, the head has articulated pitch bearings. As opposed to later constructions where pitch is also realised by bending the blade in the desired direction.
Therefore it is usually referred to as a semi-rigid system.
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Old 18th Mar 2015, 11:31
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Smile

Ready2Fly, I'd probably get more search results for "big knockers" too, but that's not what the OP asked about either.
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Old 18th Mar 2015, 11:44
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@shy the BO105 has a rigid rotorhead.
All the blade movement comes from a softer part in the blade base that allows lead and lag movement.
No, I disagree! In the strictest sense it's definitely a semi-rigid system. There are pitch change bearings in the blade cuffs. A rigid rotor has no bearings at all.
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Old 18th Mar 2015, 12:02
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Some of them that should have been tethered were quite rigidly out of plane me thinks. coaat, hat, last Guinness of the happy paddy's day etc.
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