what are tethering head helicopters
 

If anybody cud explain it in simple terms

Link with pics
 

Here you go:

Helicopter Aviation

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

The Lynx, BO105 series etc all have four main rotor blades, too. Both are semi-rigid systems.

What is a tethered head? Only references I can find are to RC models.

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. :ok:

Praf: no such thing. Must be a radio controlled thang...............

@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.

@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.

Ready2Fly, I'd probably get more search results for "big knockers" too, but that's not what the OP asked about either.

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. ;)

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.