what are tethering head helicopters
Joined: May 2006
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From: On the right of the clowns and to the left of the jokers
Joined: Nov 2000
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From: White Waltham, Prestwick & Calgary
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
"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
Avoid imitations
Joined: Nov 2000
Aviation Qualifications: ATPL
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From: Wandering the FIR and cyberspace often at highly unsociable times
The Lynx, BO105 series etc all have four main rotor blades, too. Both are semi-rigid systems.
Joined: Feb 2003
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From: Germany
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.
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.
Joined: Mar 2012
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From: steady
@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.
Therefore it is usually referred to as a semi-rigid system.
Avoid imitations
Joined: Nov 2000
Aviation Qualifications: ATPL
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From: Wandering the FIR and cyberspace often at highly unsociable times
@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.
All the blade movement comes from a softer part in the blade base that allows lead and lag movement.
