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Chris,
I can affirm your points as I have been using the 3/32 SS welding rod since
you first suggested it. No problems in all these years.
Scott Krueger
320 slo built, fly'n since 96
In a message dated 3/5/2011 9:18:28 A.M. Central Standard Time,
chris_zavatson@yahoo.com writes:
Ah, but there is a way to stop it. It works, is inexpensive
and has the added benefit of being the closest tolerance hinge tested to
date. This has been discussed previously, but is worth going over
again.
The key to preventing wear in the standard MS hinge is to
distribute the load across sufficient area of the hinge
material. The MS hinge pin doesn't do this. Its diameter
is too small. Here is where the welding rod comes in.
Because of its close tolerance fit, contact stresses are reduced to
an insignificant level. This effectively translates into
an infinite hinge life. I tried
this on my plane ~11 years ago and there is
still no sign of play.
The point of the original post was in regards to shaking doors and play
in the hinge and rod end bearings. This is where the welding rod
approach is better than anything we have seen to date. It has the
least inherent play. I would caution against using any hinge with nylon
bearing material in this application. In the gear
door installation, the actuator is attached out in front
of the hinge. This places a disproportionate load on the very first
hinge element. Nylon is only good to ~2,000 psi and by its very nature
will creep under load. Over time, this will only add to the play in
the hinge and require continuous readjustment to the doors.
Chris Zavatson
N91CZ
360std
Lots of
talk about hinges on the gear doors. Consider that aluminum by its
nature wears with time, friction and the elements. Probably no way to
stop it. That means the moment you put that aluminum hinge in service
the fit between the pin and the hinge begins to wear and gradually become
more and more sloppy.
Carbinge is
designed with a nylon bearing that in our studies overcomes this quandary.
Shameless
plug,
John
Barrett
Leading
Edge Composites
www.carbinge.com
From: Lancair Mailing List [mailto:lml@lancaironline.net]
On Behalf Of Chris Zavatson
Sent: Friday, March 04, 2011
6:14 AM
To: lml@lancaironline.net
Subject:
[LML] Re: Lancair 360 Inner Doors
If you extend the hinge
line all the way forward to the leading edge of the door when you change out
the hinge, it will stop the premature wear. The attached photo shows
this mod with the original door installed. It will not stop all the
'shaking in the breeze' as seen in the video link, but will help save the
hinge. The moment arm for the actuator is still too small for the size
of the door.
Rod end bearings come in
different flavors. This goes for all the spherical bearings as well,
If you upgrade to a better alloy, it will prevent the play from
developing. The load rating will seem excessive, but you
will never have to replace the bearing for the life of the
plane. Tolerances will remain much better. You can
download the Aurora catalog, for example, and see how different series
have different load ratings for the same dimensions. You'll need to go
to a bearing place like Motion Industries to get these.
From: JON ADDISON <jraddison@msn.com>
To:
lml@lancaironline.net
Sent:
Thu, March 3, 2011 12:37:46 PM
Subject: [LML] Lancair 360 Inner
Doors
Lancair 360 Inner Doors... again...
I have
the larger inner doors and they vibrtate badly. (Someday I'll try to
get the 3 piece carbon fiber doors)
But for now: I'm in
the process of changing the worn hindge to an extruded aluminum hindge with
an "over size" 3/32 " (.095 ") stainless steel welding
rod.
Plus replacing worn rod-end bearing. (New from
Lancair this morning)
Considering remaking the attach channel
that connects the rod end bearing and actuator to the door. ie making
it twice as long as the origional.
Wondering if the
attach point under the seat needs to be make tighter with possibly metal
sleeves after drilling out the attach bracket on
flloor.
Also, considering making a tiny spoiler 1/8 " or so
high and temp mounting on aft / lower edge of door to stabalize it (and
probably loose a knot).
Opinions and fixes that worked??
(Except the carbon doors which I can't afford yet.)
And also
does anyone know if the inner door actrator can be rebuilt... both or mine
leak a bit.
Jack Addison
N360JS Sisters,
Oregon
No virus found in this message.
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03/03/11
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