Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

bifilar vibrations 3P

bifilar vibrations 3P

bifilar vibrations 3P

I´ve began to work on the Sikorsky S76 just a couple of months ago and have a question.
Where could I find info about bifilar vibrations and the way the S76 dampens them.
I´ve seen in the configuration that it has a damper consisting of four masses with an excentrical movement. The problem is that this kind of vibration is absolutely new for me. My experience is with the Superpuma model from Eurocopter, and the only vibrations there where the ones from tail and main rotors. Don´t know how does it appear nor the mechanism to reduce it.


RE: bifilar vibrations 3P

Thanks a lot for your response. It´s been very useful.
Anyway I still have a question not answered in that forum (better said answered but not understood).
As it seems when the blade makes it´s way through the air it passes from bearing more to less weight in one roll.
Multiplied by the number of blades makes it normal to have n excitement cycles in one roll (or at least an armonical number)
So... why do the dampers work on n+1/n-1?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close