Re: coughlin brake mount


fionapple
 

No install yet, but thanks for the tips (the threaded-rod hole size
probably provides all the necessary play). I'm not convinced I have a
problem with braking any more; I'm generally within 3-5' of centerline
on braking even at 65 mph. I did have a couple instances on abrupt
deceleration that felt like tailwheel floating. I installed a video
system and control display to debug that, but I haven't been able to
reproduce it with the cameras rolling. Maybe I need to stick Jim's
cracked taxi prop back on :)

Wes

--- In Q-LIST@yahoogroups.com, "Sam Hoskins" <shoskins@...> wrote:

Wes, you can use coke can aluminum for shim material. I think I recall
opening up the through hole in the threaded rod one letter-drill
size. It
needs to be free as it slides.

How is the installation progressing?

Sam



_____

From: Q-LIST@yahoogroups.com [mailto:Q-LIST@yahoogroups.com] On
Behalf Of
wesisberg
Sent: Friday, September 29, 2006 12:26 PM
To: Q-LIST@yahoogroups.com
Subject: [Q-LIST] Re: coughlin brake mount



That does help, Sam, esp. mounting instructions.

Not sure how I can better describe my concern in words. Let's say the
mount is an uppercase "L" where the bottom part of the L is clamping
to the rotor which is spinning at 5,000 RPM (90mph) with a run-out of
.03". Then the top of the L will be wagging at the same speed and, if
the ratio top:bottom is 2:1, an amplitude of .06". However, the slide
only permits movement along the top axis (i.e., L jumping up and down,
not teetering side-to-side). Nor am I sure the thing will loosen or
wear visibly before breaking, so I'd at least have some notice during
preflight.

Agreed that I should avoid the issue by removing run-out, but the
rotor is new and that's as close as I could get; maybe I should get
finer shims.

Thanks -
Wes

--- In Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com, "Sam
Hoskins" <shoskins@> wrote:

Wes, I'm not clear on what you are saying here. Is it the fact
that the
disc is not flat that is causing concern, or that it is off-center
of the
center point of the axle?

If the disc is not flat, yes it should be shimmed as much as flat
as you
can. However, the slide feature of the mount makes that condition
a lot
more tolerable than the other mounts. That's why I like it. 0.030"
shouldn't be a problem.

Here is how I got the best alignment between the mount and the wheel:

Install everything, but don't yet drill the brake mounting holes
into the
wheel pant.

Now, pull the brake handle and lock the caliper onto the disk. This
will
cause the caliper to align itself with the wheel.

Next, stuff the void between the brake mounting plate and the
wheel pant
with flox. Voila! Perfect alignment. Don't drill the holes until
you have
verified everything is to your satisfaction.

I just uploaded another photo to my Q-List folder. This link may work:
http://ph.groups.
<http://ph.groups.yahoo.com/group/Q-LIST/photos/browse/b877>
yahoo.com/group/Q-LIST/photos/browse/b877

You want to make sure the through hole in the threaded rod gives
enough
clearance and the threaded rod doesn't need to be too long. Maybe
1 ΒΌ"?

Does this help?

Sam

_____

From: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com
[mailto:Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com] On
Behalf Of
wesisberg
Sent: Friday, September 29, 2006 1:21 AM
To: Q-LIST@yahoogroups. <mailto:Q-LIST%40yahoogroups.com> com
Subject: [Q-LIST] coughlin brake mount - too rigid?



I have the Coughlin brake mount parts (thanks Jon and Sam and ...) but
noticed (late) that it permits only movement parallel to the disk
rotor. My rotor has some run-out (down to about .03" after
reshimming, still noticable) which it seems to me would cause chafing
on the slide if not significant vibration where the mount attaches to
the wheelpant. By contrast, my mount (see qtalk 1, Peay) permits
about 5 degrees of twist, enough to tolerate a bit of run-out.

So for those who've used the Coughlin mounts, do you have any run-out
that they have to tolerate, and how many landings have you used them?

Thanks -
Wes











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