P

pa24

Member
I have run 1/4" metal tubing from the pitot to the wing root, but want to run 1/4" plastic tubing inside cockpit to the several instruments that require pitot feed since the instruments all have plastic connectors. What can I use to make a good connection from the metal tubing to the plastic tubing at the wing root. I am using the poly tubing supplied by Vans. Any suggestions would be appreciated. Thanks.
 
Try heating the plastic tubing in hot water before slipping it as far as possible over the metal tube. Finish to the metal. Make sure the joint area is well supported so that there is minimal if any tension load on the joint in service. It's what the Van's drawings show for the carburetor small drain hose that runs runs through the lower firewall flange.
Jim Sharkey
RV6 - Getting there!!
 
This what I meant to post :rolleyes:

Try heating the plastic tubing in hot water before slipping it as far as possible over the metal tube. Finish by adding a couple of tightly twisted loops of safety wire around the joint to clamp the plastic to the metal. Make sure the joint area is well supported so that there is minimal if any tension load on the joint in service. It's what the Van's drawings show for the carburetor small drain hose that runs runs through the lower firewall flange. Simple, light and cheap - don't know how well it works yet though :)
Jim Sharkey
RV6 - Getting there!!
 
pitot tube fitting

PA24
I used a Safeair pitot system that came with fittings but you could purchase a AN816 4D nipple that will screw into the An818 nut. One end of the An816 is 1/8 pipe thread, then purchase a 1/8 pipe female barbed nipple at your local Lowes or Home Depot plumbing section. The barbed end will give better protection from the tubing slipping off.

Oldgeezer
RV9A
 
Use one of these from Wicks Aircraft. Simple, cheap, painless.
Part no.262N-04

880dha1.jpg
 
I used a rubber hose sliped on about 1.5 inch over the metal. Same with the plastic hose . must be a tight fit !. 2 cable ties per side will secure it. Seen this done before and if done properly will not leak. EJ
 
jlfernan said:
Use one of these from Wicks Aircraft. Simple, cheap, painless.
Part no.262N-04

880dha1.jpg
Click to expand...

Yup, me too. The bulkhead fitting allowed me to secure it on a piece of angle to the side of the fuselage. Not that it needs to be, but I felt better having it secured and not flopping around in the wing root.
Works well.
 
jlfernan said:
Use one of these from Wicks Aircraft. Simple, cheap, painless.
Part no.262N-04

880dha1.jpg
Click to expand...
Have you had your system leak checked yet? Is that fitting designed for aluminum tubing? I didn't think it was...

Aircraft Spruce sells 1/4" ID silicone tubing designed for exactly what you need. It's intended to slip over the ends of two pieces of tubing, regardless of their material.
 
dan said:
Have you had your system leak checked yet? Is that fitting designed for aluminum tubing? I didn't think it was...

Aircraft Spruce sells 1/4" ID silicone tubing designed for exactly what you need. It's intended to slip over the ends of two pieces of tubing, regardless of their material.
Click to expand...
It works great for pitot. I had a very slow leak when tested before flying, however, my DAR determined that it was not an issue for pitot and could have possibly been the other fittings or the instrument istelf. I have three airpseed indicators including GPS. Spot on all three. It probably was not designed for aluminum tubing, but was recommended to me by a local, well respected, supply house and multiple other RV builders/users of said fitting.
I would use it again.
 
My union is super simple - as others have said, slide the next sized piece of tubing over the joint - fits tight, no leaks, hard to remove (would probably have to slice it open with a razor knife to get it off).

Paul
 
Thanks guys - appreciate the response! I guess I wasn't thinking in simple terms but I think I will go with what Dan and Paul suggest - using a piece of plastic tubing to connect the two together. Thanks again!
 
OR

A piece of 1/4" rubber fuel hose to act as a joiner...I used a couple of mini hose clamps for belt and braces.

Frank 7a
 
dan said:
Have you had your system leak checked yet? Is that fitting designed for aluminum tubing? I didn't think it was...

Aircraft Spruce sells 1/4" ID silicone tubing designed for exactly what you need. It's intended to slip over the ends of two pieces of tubing, regardless of their material.
Click to expand...

X2. Don't even need clamps.
 
Lars said:
X2. Don't even need clamps.
Click to expand...


I third (or even more) this vote. This is what I did and can vouch that this makes a VERY good connection. I would definitely have to cut the silicone tubing that joins the metal to the Nyloseal to get it to separate.
 
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