Message-ID: <19981105225033.3208.qmail@www05.netaddress.usa.net>
Date: Thu, 05 Nov 1998 22:50:33
From: Dan Schaefer <dfschaefer@usa.net>
To: lancair.list@olsusa.com
Subject: brake lines
Mime-Version: 1.0

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Routing on the brake lines (Nylaflow) should use gentle bends, should
not impinge on a sharp edges, and operational flex, such as in  acommodating the 90 degree change of direction during gear operation, should be spread over as much length as can be arranged. Since my gear pump is ahead of the main spar, the lines ran to the rear thru the 
pass-thru under the spar, aft to run behind the small curved, 
rear bottom of the seat and out thru the inboard close-out rib just 
forward of the rear spar. The lines were then run along the forward 
side of the rear spar in the wing-stub, thru clearance holes (later 
secured with RTV) in the half-rib, to the main gear upper fore-and-aft 
shaft. Attaching the lines at this transition point with tie-wraps 
no closer than about 12 inches or so where the 90 degree flex occurs 
will keep the stress on the plastic low.

I've been using the Nylaflow brake lines as per the original 235 kit
without obvious trouble for four years and over 460 hours. I've done
detailed inspections of the whole thing and have given very close 
attention to the lower termination (connection to brakes) because, to
tell the truth, I was more than a little bit skeptical about using 
plastic brake lines too. To date, on my second or third set of brake pads, I haven't found a thing (visible) wrong. But you guys are 
making me nervous enough to re-think the situation and I'll probably 
get the Nylaflow out of there and do a retrofit the next time the 
plane is down for major maintenance.

The only reason I didn't do it originally is because it would require
the use of a flexible line at the upper shaft pivot and again down at 
the main truck due to the flexure there. Adding two short flexible 
sections per side or one long one (from top to bottom) per side adds
no less than four, and as many as eight, connection points to the 
system - and any time you add connection points to a hydro system, 
the reliability goes down a little. SO I opted for the system in the 
manual because there were no intermediate break points and give the 
Nylaflow lines a try. 
I can't vouch for my reasoning, but that was my thinking at the time.

Cheers,

Dan Schaefer


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