REFLECTOR: Elevator torque tube center bearings

[KeithHallsten]

Advantages:
1.  About an inch of overlap between the support surface and the torque tube, rather than about a quarter inch. (Safety.  Security of primary flight control)
2.  Much lower friction in the elevator control system. (feels nice!)
3.  No slop, galling or grinding in the torque tube bearing. (feels nice)
4.  No wear due to grinding aluminum hole with steel tube. (stays right without maintenance)
5.  No wear of paint on steel tube due to rubbing on aluminum (keeps corrosion protection in place)

Disadvantages:
1.  The bearings cost more than the little block of aluminum.
2.  The system weighs a couple of ounces more.
 
  ----- Original Message ----- 
  From: Douglas Holub 
  To: Velocity Aircraft Owners and Builders list 
  Sent: Thursday, October 07, 2004 8:09 AM
  Subject: Re: REFLECTOR: Elevator torque tube centerbearings(Was:FrontVibration90% resolved)


  What's the advantage, again?
    ----- Original Message ----- 
    From: KeithHallsten 
    To: Velocity Aircraft Owners and Builders list 
    Sent: Wednesday, October 06, 2004 10:10 PM
    Subject: Re: REFLECTOR: Elevator torque tube centerbearings(Was:FrontVibration 90% resolved)


    That's exactly the same mod I incorporated.  I recommend it extremely highly; I think it should be the standard design for all Velocities.  I got the bearings from Aircraft Spruce - part #KSP4.  They were about $20 each when I bought them in 2001.  I used an AN4 bolt, but I don't remember now whether it was a -16 or a -17.  I used large washers (washer OD just a bit smaller than the bearing OD) on both sides of both bearings; in the extremely unlikely event of bearing failure, the washer ODs would become a temporary bearing surface.

    Keith Hallsten

      ----- Original Message ----- 
      From: Al Gietzen 
      To: 'Velocity Aircraft Owners and Builders list' 
      Sent: Tuesday, October 05, 2004 9:25 PM
      Subject: RE: REFLECTOR: Elevator torque tube center bearings(Was:FrontVibration 90% resolved)




      Tony;



      I installed ball bearings that slide inside the torque tube. The bearings mount to the center pivot support with a ¼"bolt.  The bearings are from Aircraft Spruce.  It has been years since I have done the mod so I don't have the bearing #, but it is ¼" i.d.; and the nearest o.d. to the inside tube dimension.  I recall having to ream the tube i.d. just a bit.  Be sure to get a "self centering" bearing where the outer race can move relative to shaft alignment because the TT has to slide over at a bit of an angle when installing.  It makes a strong, smooth pivot. Old photo attached.



      I left the TT as long as possible, and cut it back around 180 degrees to give clearance from the support to give as much insertion into the tube as possible.  Photo attached.



      It may be that I also bought a "full dimension" bolt (.250" diameter) to fit snugly to the bearing i.d.



      Al





      Subject: Re: REFLECTOR: Elevator torque tube center bearings (Was:FrontVibration 90% resolved)



      Tony Babb wrote:



      > I'll be doing my elevators shortly. I've watched the video multiple 

      > times but can't visualize this design improvement. Are there any 

      > photos available?

      >  

      > Thanks

      >  

      > Tony

      > SEFG





--------------------------------------------------------------------------


      _______________________________________________
      To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

      Visit the gallery!  www.tvbf.org/gallery
      user:pw = tvbf:jamaicangoose
      Check new archives: www.tvbf.org/pipermail
      Check old archives: http://www.tvbf.org/archives/velocity/maillist.html


----------------------------------------------------------------------------


    _______________________________________________
    To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

    Visit the gallery!  www.tvbf.org/gallery
    user:pw = tvbf:jamaicangoose
    Check new archives: www.tvbf.org/pipermail
    Check old archives: http://www.tvbf.org/archives/velocity/maillist.html


------------------------------------------------------------------------------


  _______________________________________________
  To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector

  Visit the gallery!  www.tvbf.org/gallery
  user:pw = tvbf:jamaicangoose
  Check new archives: www.tvbf.org/pipermail
  Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.tvbf.org/mailman/private/reflector/attachments/20041007/676a5e77/attachment.htm