Brakes

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Bob Mears

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Joined
Sep 1, 2004
Messages
88
Location
Texas
Are any of you using the plastic brake line? My kit came with plastic and I'm having difficulty in trusting it. I ran it for years in go karts without incident....but that ain't an airplane.

Bob
 

Dana

Super Moderator
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Apr 3, 2007
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Location
CT, USA
Haven't had a problem with the plastic brake lines on my plane... and I figure brakes are less critical on a plane than on a kart...

-Dana

Welcome to the Federal Bureau for Reducing Bureaucracy!
 

RacerCFIIDave

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Joined
Feb 8, 2008
Messages
412
Location
Asheville, NC
As a former Formula Atlantic Crewchief... I can say that even the term "plastic brake lines" scares me silly...
Karts, Cars, Planes...anything... brake lines should be braided stainless steel... period
They provide better braking performance and they live FOREVER... yes theyre expensive...but you only buy them once...

Federal Bureau for Reducing Bureaucracy...LOL
I'm surprised there isnt such a thing...with a billion dollar budget...:depressed

In Liberty,

Dave
 

Dana

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Well, the way I look at, my plane isn't even supposed to have brakes... I treat them as a convenience during low speed taxi, at speeds where even if one fails, the other will still stop me just fine.

But it did give me pause... and in a faster, heavier, or enclosed plane I probably wouldn't want the plastic.

-Dana

I don't trust a government I can't shoot back at.

-Dana
 

Jeremy

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Joined
Feb 23, 2003
Messages
75
Location
Salisbury, England
It's worth noting that stainless steel braided brake lines are actually just plastic pipes with a bit of stainless braid over them to provide abrasion resistance.

The stainless braid doesn't make the pipes any stronger, or withstand higher operating pressure, it just makes them look pretty and stops the plastic getting damaged.

If the pipes are reasonably well protected from damage as a consequence of their location, then there is no merit in adding the extra weight of the stainless braid, in my opinion.

Jeremy
 

orion

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Joined
Mar 2, 2003
Messages
5,800
Location
Western Washington
Also, the plastic is actually more durable and capable than first glance might indicate. Some time back I was working on a marine project in the installation of a dinghy davit system. The mechanism used 3,000 psi hydraulics and all the interconnecting lines (hydraulic cylinder and rotary actuator) were plastic. The material had a burst pressure rating far in excess of the system's 3,000 psi and had Coast Guard certification for the application.
 

herbrose

Active Member
Joined
Jul 11, 2007
Messages
30
Location
Sacramento PA
Bob:

Like you, I also had my fears, but after talking to the people at Matco, and my son who works for Johnson Aerospace, my fears were removed.

Just my two cents here!

Herb Rose N657HR
 

Midniteoyl

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Joined
Sep 3, 2003
Messages
2,406
Location
Indiana
Have to agree.. the SS braided are plastic inside, and plastic, being more flexible, holds up better that rigid.
 

jscott

New Member
Joined
Feb 26, 2008
Messages
2
Location
Los Alamos, NM
I have some experience with the plastic brake lines. I generally do not recommend them. However, they can be used safely if used properly.

Installation: The darned things stretch under pressure. I found that using 1/4" Nylaflow tubing had enough expansion under pressure to use up much of the effective braking pressure. I found that 3/16" tubing stretched much less and gave much better braking action.

You really don't want to use any of the plastic pressure lines like Nylaflow at the brakes if you have a high speed plane with tight wheel pants. Two bad experiences with them within our EAA Chapter over the last 25 years.

An RV-4 had a long taxi in at an air show while apparently dragging the brakes a bit during taxi. When she attempted to stop, both Nylaflow brake lines had softened and blew off under pressure. She spent the air show finding parts to repair her plane to get home.

An EAA member had built a Defiant that he had flown for a few years, then had replaced the rear engine and was testing the new engine configuration. He had done some hot runs down the runway with heavy braking at the end of the runway. The brake lines melted, sprayed 5606 fluid on the hot brakes starting a dandy fire. The aircraft was burned to the ground in the ensuing fire.

I do have Nylaflow brake lines on one of my planes and have not had any issues with them in 11+ years of use. However, the Nylaflow tubing terminates at the gear leg where I have aluminum tubing out to the brakes. Nylaflow is useful in areas where you want light weight flexible tubing. However, it should never be used in an area that may be exposed to significant heat.

Jeff
 

RacerCFIIDave

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Joined
Feb 8, 2008
Messages
412
Location
Asheville, NC
The brake lines melted, sprayed 5606 fluid on the hot brakes starting a dandy fire. The aircraft was burned to the ground in the ensuing fire.

Yet another racecar technology that lots of us should add to our homebuilts...

The onboard fire supression system... 10lbs... and $700 coulda saved that Defiant... Aqueous Film Forming Foam based systems are available from Pegasus Racing...some models even use a Carbon cylinder...nice and light...

In Liberty,

Dave
 

orion

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Joined
Mar 2, 2003
Messages
5,800
Location
Western Washington
Not much good if the flame is superimposed onto the structure from the outside.

However I've known a couple of folks who used a simple Halon system in their engine cowl. Also realtively light and simple but none have had an on-board fire so we don't really know how effective.
 
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