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Crhis Z’s videos and his observations are interesting and productive. He does not follow through with Carbinge to the same stage he did with the aluminum extruded hinge. You can match fit pins to each hinge and acquire a very snug fit with Carbinge as easily as you can use a reamer to achieve a matched fit with the aluminum and SS welding rod. I am admittedly biased in that my company produces Carbinge but I think the sample that he showed indicates greater play in the stock aluminum hinge vs the Carbinge sample. I suspect that this could vary somewhat sample to sample, but we purposely strive to make our tolerances tighter than the aluminum hinges. It is quite possible that using the LPS2 lubricant could reduce or remove the risk of corrosion with the aluminum hinges. I have not seen examples of this or tried it out. However I have seen many, many airplanes, my own spam cans included, that have dark streaks on the airframe aft of every aluminum hinge on the airplane whether it is in a trim tab, a flight control surface or a door. The experience in the fleet is that these hinges do fret and corrode. It’s nice to think that the above mentioned lubricant could eliminate that problem across the entire aircraft fleet. Thanks for the tip Chris. John Barrett Leading Edge Composites www.carbinge.com From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Chris Zavatson
Sent: Monday, November 28, 2011 7:53 AM
To: lml@lancaironline.net
Subject: [LML] Re: Legacy vibrations resolved 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. Here is a comparison of four hinge options examined and tested several years ago. -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. 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. 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
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