Nyla-flo

[Dave S]

Good afternoon,

Got a question that I haven't found much info on......Regarding the Nylaflo tubing that we use for KF brake systems, is there any info suggesting what the useful life, half life or replacement schedule should be for this product?

Like other aircraft with full castering/non-steering nosegear, those of us with a trigear KF depend quite heavily on the brakes for ground operations from time to time.

Thanks,

Dave S
KF7 Trigear
912ULS, Warp Drive

[DesertFox4]

Good question Dave.

I've never heard discussions on replacing Nyla-flo on a time based schedule.

I have heard of failures on the Nyla-flo.
I think all were at a fitting and not a rupture of a line.

The Nyla-flo tubing works real well and saves weight no doubt over the stainless I chose to install some 10 years ago. I've had zero problems with the stainless, yet.

[HighWing]

Nyla-flo is standard on the Lancair IV a high performance plane that has landing speeds about two times ours and gross weights about two times the Sevens. I think Steve's comment is pretty accurate. I had problems once, when the parking brake partially engaged on landing and I taxied to the hangar with the brake about half set. Heat from friction melted the tubing at the caliper that resulted in a slow leak. I guess my thinking is to route it so it won't come in contact with stuff on rough strips and inspect it regularly.

A personal opinion - I think we should include inspecting all brake visible brake lines and fittings during each pre flight inspection and use a comprehensive check list for the annual condition inspection. I would check every fitting for moisture with a paper towel. I find that you can see a wet spot on the towel where you can't see moisture on the fitting. I would also check for chafing and would replace the line if I saw any. I do agree that with our differential braking and the steering we do with it, the brakes are critical.

[dholly]

Shortly after I bought my 1995 built KF4-1200, I decided to replace the brake lines as part of my back in service maintenance and I'm very glad I did. Looked ok but I was shocked at how hard and brittle the line looped between the gun-drilled spring gear to caliper had become. Definitely a problem waiting to happen ie., one bump on an off field landing or inadvertent kick of a foot could have contributed to potentially serious situation.

[DesertFox6]

UFF-DAH!

A buncha years ago, most of the Desert Fox Squadron (we still numbered well less than a thousand at the time) was two-hopping back home to Arizona with an over-nighter at Harris Ranch, CA (3O8) from a fly-in at Lowell Fitt's palatial spread on Cameron (Air) Park. That was the last x-c trip I ever made with the original, supplied, Nyla-flo brake lines.

While leading the back-taxiing Desert Fox daisy-chain en masse down Runway 14 for a 32 departure the next morning, I suddenly had no brake pressure on one side but plenty of lubrication on my diamond-gloss coated pine floorboards! The Nyla-flo line had worn through due to constant flexing just above the brass fitting on my right pedal's lower master cylinder fitting. Our six-ship (DF1 through DF7 sans DF3 who was probably watching and snickering from above) immediately did a one-eighty and taxiied back to the parking area for a mass-assessment and mob-mumbling moment.

In short order we decided what parts were needed, DF7 flew me over to Paso Robles, his original hometown, where a buddy of his took us to visit the aviation department of the local "Home Despot." The rest of the squadron headed for home, but only two nerve-wracking hours later we (DF7 and selves) were back in the air, if only somewhat further to the rear of the trans-desert-gaggle: A testament to the DF Squadron's wingman-support ethic and the power of a subsequently substantial investment in the output of a local micro-brewery for DF7.

A trip to a local Phoenix hot-rod & speed shop produced the sexy stainless steel braided lines that now adorn my Kitfox's legs from her pedals all the way down to her paws. Like DF4 said earlier, it was a failure at the fitting but now "no problems" and it's been well over a decade since. Insuring that you don't have any binding or inordinate flexing above the brass fittings will probably keep you in good stead, but an energetic eyeballing every couple months is probably prudent preventative medicine.

I usually don't like to tell this story for fear of making some folks worry needlessly about their birds, but I'll blame poor Dave S for bringing it up in the first place: "HE STARTED IT FIRST, MOM!!"

"E.T."
(And I'm glad you did Dave S; another war story to help folks understand the vagaries of experimental aviation is always a good idea, thank you!)

[Dave S]

DF6,

Thanks for your informative yet humorous update.......I'll take the bullet.....thick skin & lots of patients from a lifetime career of playing the role

When I get around to it, I need to collect & share a photo of the assembly I ended up with between the calipers & gear leg.

Love your idea of the auto braided lines

Dave S