Chris,

 

You are way too neat.  I agree with everything you have said.  I did try the Teflon spaghetti trick and it does deform and creep leaving one with even looser hinges.  I switched to the 3/32 SS rod years ago on your suggestion have enjoyed nice tight hinges ever since.  While I used the ream for a few burrs on older hinges, it is unnecessary on new MS hinges although the fitting is a bit snug.  Of course, grinding a gentle point into one end of the pin made easier insertion for the relatively short hinge sections on the LNC2.

 

As to neatness, my control surface hinges are hidden beneath Mylar gap seals and never get lubricated.  All my trim is controlled internal to the aircraft so there are no tabs.

 

Scott   

 

You might consider using LPS2 on your Carbinge hinge pins.  This should help with the corrosion and the need to use Scotchbright to clean them.  LPS2 has worked very well on the reamed aluminum/stainless combination.  I use it to clean/lube my hinges during each annual condition inspection.  Below is a link to a clip showing both new reamed hinge material and a reamed aileron hinge after nine years and 850 hours TIS.  The aluminum hinges are on track to outlast everything else on the airframe. 

http://www.n91cz.com/HingePlay/Ream850hours.wmv

 

Here is a comparison of four hinge options examined and tested several years ago. 

 

http://www.n91cz.com/HingePlay/HingePlayComparison-hires.wmv

 

Conclusions were:

-The best fit was obtained using SS welding rod with MS20001 hinge material.

-Nylon or Teflon inserts or sleeves could not take high loads.  (i.e. asymmetric actuation such as outback flaps and inboard gear doors)  They would deform and creep and had to be replaced.  (40,000 psi for aluminum vs. 2,000 psi for Nylon)

-SS welding rod had the highest load carrying capability of all the options.

-Time and use have proven the durability the MS20001/SS welding rod combination to be outstanding. 

 

 

Chris Zavatson

N91CZ

360std

www.N91CZ.net

From: John Barrett <jbarrett@carbinge.com>
To: lml@lancaironline.net
Sent: Friday, November 25, 2011 8:11 PM
Subject: [LML] Re: Legacy vibrations resolved

For any production hinges a tolerance is required between diameter of the orifice and diameter of the pin in order to avoid having to reject lots of parts that have too much friction.  For this reason, the amount of play in Carbinge vs aluminum is likely to be similar.  In either case, you can substitute different size pins in order to diminish the play.

 

A major and important difference between the two is that with aluminum hinges I don’t think you can avoid corrosive wear of the inside diameter of the hinge over time.  Therefore aluminum hinges will always become looser over time and will tend to develop the play being discussed even if during installation the parts are match fit to avoid play.

 

Carbinge in our tests does not wear over time.  The fit at installation should remain the same. 

 

In either case, the pin itself can corrode.  This will usually result in the pin being more difficult to remove because of rust deposits on the pin.  It is good with Carbinge applications to occasionally remove the pins and clean them with Scotchbrite before re-inserting.  Stainless Steel pins can decrease this concern but they tend to be more brittle and can fail due to breakage in some applications.

 

Regards,
John Barrett

Leading Edge Composites

 

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of marv@lancair.net
Sent: Friday, November 25, 2011 6:11 AM
To: lml@lancaironline.net
Subject: [LML] Re: Legacy vibrations resolved

 

Posted for "Bill Wade" <super_chipmunk@roadrunner.com>:

  I agree. I’m using Carbinges on my IV-P MG doors and I thought they had too
much play. I think the stock pins are suitable when you’re attaching cowlings
or other curved surfaces but I wanted a tighter fit for use as a hinge,
especially if they’d be used for trim tabs.
 
  I found a source for precision ground VAR stainless
http://www.smallparts.com/stainless-precision-ground-straightened-vacuum-arc/dp/B003R50276/ref=sr_1_1?sr=1-1&qid=1322133332&filterBy.material_browse=16414
. I tried a range of diameters and found 0.083 was a good fit. –Bill Wade
 
From: Chris Zavatson
 Sent: Wednesday, November 23, 2011 10:05 PM
 To: lml@lancaironline.net
 Subject: [Norton AntiSpam][LML] Re: Legacy vibrations resolved
 
 The elevator trim tab is perhaps the most neglected control surface that can
really ruin your day.  The goal for us should be to remove all play from the
trim tab system.  There are many ADs and service bulletins written against
certified planes specifying the acceptable limits.  We don't have the luxury
of such a guidance and thus only find the limits through experiences conveyed
by others that have stumbled across the edge.  Unfortunately the inherent play
in Carbinge is similar to that of stock MS hinge material and will not improve
the situation described in Steve's post.  
 I think Randy's post is also referring to the spherical bearings used in the
tail of the 320/360 MkII and the Legacy in addition to the trim tab hinge
(Randy, correct me if I am wrong).  The spherical bearing can be upgraded to
some made to tighter tolerances and with better alloys.
 
 Chris Zavatson
 N91CZ
 360std
 www.N91CZ.net