Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Flutter

Matronics Email Lists Forum Index -> Lightning-List

View previous topic :: View next topic

Author Message

lerch268(at)bellsouth.net
Guest

Posted: Sat Sep 10, 2011 5:37 pm Post subject: Flutter

Folks,  Just bought N8938T, serial #62.  The aircraft has a total of 150 hours.  

Today two of us made the first flights since purchase.   All went well until we 

got up to about 125 IAS and encountered some light turbulence.  At that point we 

started getting a low frequency, high amplitude flutter in the elevator.  This 

lasted for 3-4 seconds.  Each time we hit a thermal it would happen again.  It 

does not occure below 90 IAS.  This bird has "feathers" on the underside of the 

horizontal stabilizer.  Could these cause this condition?  Has anyone 

encountered or heard of some one that has?  Any info would be appreciated.  We 

suspect an out of balance elevator.  Thanks in advance,  Ralph Lerch  

lerch268(at)bellsouth.net  cell 828-266-2064

- The Matronics Lightning-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Lightning-List

nick(at)flylightning.net
Guest

Posted: Mon Sep 12, 2011 6:02 am Post subject: Flutter

--

- The Matronics Lightning-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Lightning-List

N1BZRich(at)AOL.COM
Guest

Posted: Mon Sep 12, 2011 6:59 pm Post subject: Flutter

Ralph,

     Congratulations on your Lightning purchase.  I  know when you get this current issue fixed, you will really enjoy the  airplane.  But to start out with - what the heck are "feathers"?  With  over 40 years in aviation, I have never head that term associated with airplanes  - other than feathering a propeller, and I'm sure that has nothing to do  with your concern.  What am I missing here?  

     Nick has already mentioned checking for possible  "slop" or looseness in the elevator control system, and this is the first thing  to check.  But I have some other questions as to your airplane's elevator  set up.  First, do you still have the original artificial pitch trim set up  with bungees, or does your Lightning have the new trim tab set up.  If  so, also make sure the trim tab hinge is not sloppy or loose.  

     Also, does your elevator have the original set up  with the aerodynamic counter balance outside the outside hinge.  This  aerodynamic counter balance was good to lighten elevator forces (too light for  some pilots) and as a result, it was eliminated early on.  If you do still  have this counter balance it would tend to make any looseness or sloppiness in  the control system that Nick talked about much more noticeable.  

     As long as I am asking questions (like what are  feathers), let me also ask if the stick was moving when you felt what you  described as flutter?  With worn hinges you can sometimes get  what I would call a vibration or "buzz" instead of an actual flutter.  But  the stick does not move or vibrate.  

     So my bottom line is exactly what Nick said - check  for looseness or sloppiness in the control system.  If the airplane was  built according to plans and the control system is intact, you should not have  any concern about flutter in pitch or roll.  Again, as Nick mentioned, he  and I both tested for flutter to well above the airplane's VNE.  

 Blue Skies,

 Buz Rich

  

  In a message dated 9/10/2011 9:38:02 P.M. Eastern Daylight Time,  lerch268(at)bellsouth.net writes:

  	  Quote: 	
		  -->    Lightning-List message posted by: Ralph Leach    <lerch268(at)bellsouth.net>



Folks,  Just bought N8938T, serial    #62.  The aircraft has a total of 150 hours.  

Today two of us    made the first flights since purchase.   All went well until we    

got up to about 125 IAS and encountered some light turbulence.  At    that point we 

started getting a low frequency, high amplitude flutter in    the elevator.  This 

lasted for 3-4 seconds.  Each time we hit a    thermal it would happen again.  It 

does not occure below 90    IAS.  This bird has "feathers" on the underside of the 

horizontal    stabilizer.  Could these cause this condition?  Has anyone    

encountered or heard of some one that has?  Any info would be    appreciated.  We 

suspect an out of balance elevator.  Thanks in    advance,  Ralph Lerch  

lerch268(at)bellsouth.net  cell    se the  ies  ay                 - MATRONICS WEB FORUMS               - List Contribution Web Site  p;                             

	


 [quote][b]

- The Matronics Lightning-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Lightning-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Lightning-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum