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
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.
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.
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...