nylon vs. vinyl tubing for static

lostpilot28 · #1 01-07-2012, 05:37 PM

Last weekend I was T'ing into my static line for some pressure measurement experiments that I'm doing. I found that one of the ends of white nylon (or is it plastic) tubing that I used was split at a T, and another was completely disconnected. That prompted me to test my static system for leaks today.

After I fixed all apparent leaks, I taped over both static ports and applied negative pressure to the static line. It was equalizing at a pretty good rate - about 1500 fpm (I had my EFIS on). Clearly it's not good.

My question is, does anyone think the nylon (or white plastic, whatever it is) tubing leaks more than the softer, clear vinyl tubing? I just bought some at Home Depot and plan to replace my static lines tomorrow. Before I go through the effort, I want to see what you all think.

Walt · #2 01-07-2012, 06:24 PM

Nylo seal nylon tubing is excellent, however, I can't tell you how many static leaks I've had to repair in the rear fuselage of RV's when folks try to insert a 'T' into this hose. It's not made to expand over a T fitting, it won't seal, and if you do get it on it will eventually (if not immediately) crack and leak (no matter how much RTV you smear over it).

The other problem I see with Nylo tubing/Nylo fittings is incorrect assembly, ie: failure to use the little tube insert at each fitting.

lostpilot28 · #3 01-07-2012, 07:04 PM

Thanks Walt...is Nylo seal tubing the white stuff you get at HD?

Walt · #4 01-07-2012, 08:16 PM

Could be, but I doubt it...

http://www.aircraftspruce.com/catalo...s/nyloseal.php

jrs14855 · #5 01-07-2012, 08:30 PM

Nylo-seal is 1500 psi rated, Nylaflow 1000 psi, poly-flo 190 psi, all will work with nylo-seal fittings. The hardware store stuff is probably polyurethane tubing. Industrial hardware supplys hve the good stuff, not likely at Lowes or Home Depot.

lostpilot28 · #6 01-07-2012, 08:35 PM

What are your thoughts on using the softer vinyl tubing for static or pitot lines? I'm sure it is much lower in pressure rating and heat resistance, but neither should matter since these lines are all aft of the firewall.

Walt · #7 01-07-2012, 08:46 PM

Quote:

Originally Posted by lostpilot28

What are your thoughts on using the softer vinyl tubing for static or pitot lines? I'm sure it is much lower in pressure rating and heat resistance, but neither should matter since these lines are all aft of the firewall.

I only use cheap vinyl for abrasion sleeving, polyurethane and Nylon are ok for short connections to tees and barbed fittings.

Rick_A · #8 01-07-2012, 09:46 PM

I have quite a few connections behind my panel to the Pitot/Static lines (GRT AHRS, 3 steam gauges, AP and AOA) which I tried to do with Nylo-seal. Since that tubing has a limited bend radius, I had to put in a bunch of Tee's and Elbows. It got to be such a nightmare of fittings, I pulled most of it out and used Tygon tubing with high quality nylon barb connectors.

I still use the Nylo-seal for the long run from the static ports up to the panel and the short connections between my steam gauges.

Check out the connectors that Stein sells. I replaced some of my original fitting with those and love them. I also like the color coded tubing - wish I had in my plane.