To teeter or not to teeter

[Burgess]

Main rotor head:
To teeter, or not to teeter, that is the question. Wether it be goodly to have swift response to input and sway the main disk in likewise direction, or be it best to have stability and serenity of motion that resiteth disturbance from sober rotation of the main disk. What say thee?

OK, consider two configurations for the main rotor of a T-rex 450, using the same main rotor housing flybared rotor head:
a) Using a 3mm feathering shaft and ‘O' rings that permit the shaft to teeter about a central location within the rotor housing.
b) Using a 4mm feathering shaft and ‘O' rings that restrict all teeter movement.

In the case of (a) both paddles and blades respond quickly to any cyclic control in put. So the A & E percentages can be significantly reduced and still maintain agility.

In the case of (b)only the paddles respond quicky to cyclic input and blades resist teetering in the direction of control input. So A & E cyclic percentages need to be higher than in case (a).

Also, bearing life expectancy, especially the inboard radial bearings of blade holders.


Burgess

[tombo242]

If thou aimest for the same reation for thy given input, then it must be that thine own personal choice restricteth thy mind upon this. Hast thou not considered that the reuminations on thy thoughts wilt cause much distress in the brains of our worthy colleagues. Thou must pity their poor grey cells for it is surely that they will be in torment over this that thou has thrust upon them.

Tom.

[Burgess]

Torment, sir? '' Surely not, tis but a simple enquiry.
Well, having used both configurations with success both have merit and demerits, and thereby some correspondence to the pros and cons of rigid and floating multi blade rotors head systems, which are in vogue at present.



Burgess

[ferretmaster]

From the simplest inquiry doth surely madness spring?

By simply launching on such a lofty endeavor must surely forebode the onset of the aforementioned affliction.

[Burgess]

OK here are examples of the principles involved:

Consider this thread in congunction with point (a):
http://vps.zoniehosting.com/~rotary/forum/showthread.php?t=25601&page=3

http://www.helistart.com/RotorheadTypes.aspx

Consider this in conjunction with point (b)
HPS (High Precision System) Rotor Head
http://www.youtube.com/watch?v=h1ISKtM-dhY

[tombo242]

Facinating theories there Burgess, love it all.

Still haven't made my mind up about it though! However, it's nice to be back in the 21st century.

Tom.