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Pitot Static behind the panel

Craig

Craig

Well Known Member
I have all my pitot static connections done behind the panel. I used Nylo Seal.

I'm thinking there must be an alternative.

The Nylo Seal is pretty rigid. The Grand Rapids AHRS unit is mounted just forward of all the other instruments, and locks everything into place. I won't be able to pull the panel aft without disconnecting the pitot static lines.

Has anybody used anything more flexible behind the panel to accomodate a service loop?
 
Craig, I used Tygon S-50-HL Tubing and seamless molded nylon fittings from Mcmaster Carr. Great stuff! i/4"ID 3/8"OD. Very flexible. Tony
 
Seamless

westwinds said:
Craig, I used Tygon S-50-HL Tubing and seamless molded nylon fittings from Mcmaster Carr. Great stuff! i/4"ID 3/8"OD. Very flexible. Tony
Click to expand...

Seamless is the key for no leaks on the fittings...

The hardware store ones usually have seams from the molding process...

gil A
 
Vacuum hose works well with barbed fittings, pretty well any tubing will work. Just find the fittings that you like and then get the tubing to match.
 
PVC tubing

Norman CYYJ said:
Vacuum hose works well with barbed fittings, pretty well any tubing will work. Just find the fittings that you like and then get the tubing to match.
Click to expand...

Stay away from cheap hardware store PVC if you live in a hotter part of the continent....:)... like south of the Canadian border....:D

The PVC will relax it's grip over time and leak.. accelerated by heat... Clamps will help, but again, the cheaper clamps don't fully encircle the tubing, allowing leaks.

The previously mentioned Tygon is good stuff.

gil A
 
I'm going to look into that tygon tubing.

I really don't like the barbed fittings, though. I find that they are very difficult to remove - usually you have to cut them off.

Craig
 
You've got me thinking...

I'm pretty much in the same boat as Craig. I've got an GRT AHRS, TT AP, and backup steam gauges (AS,ALT, VSI) all connected using Nylo Seal and due to the lack of flexibility, more connectors then I really like.

My AHRS is forward of the subpanel on the left side and I'm been concerned that the pitot/static lines are going to make riveting the top skin extremely difficult.

So is the Tygon as good or better then the Nylo Seal? What's the best way to connect Tygon to the Nylo Seal? I'm OK with the way my steam gauges are connected, it's the connections between the Airspeed-AHRS-AP that would really benefit from using the Tygon.
my.php
 
Silicone rubber

Silicone rubber works very well, won't sag in the heat, won't take a set ever, and stays flexible at a few hundred degrees below zero. Add the seamless barbed fittings, and you will never have a problem. Very easy to pull off. Get the soft version from McMaster, with a thicker wall to avoid kinks.

Pete, did you get the silicone tubing you were ordering yet? Maybe you can confirm ID/wall that works well, I'm not near the plane to measure it.

Tygon, which is pvc tubing, is a real PITA to work with. Impossible to remove after a period - I don't recommend it. It also likes to kink in the heat.
 
More details on McMaster or USplastic

There are so many choices on the McMaster Carr and USplastics websites that I get totally lost. I'd sure appreciate some specifics on which tubing and which fittings (i.e. which are the seamless fittings?).

Any additional detail would be greatly appreciated. Thanks.
 
AlexPeterson said:
Silicone rubber works very well, won't sag in the heat, won't take a set ever, and stays flexible at a few hundred degrees below zero. Add the seamless barbed fittings, and you will never have a problem. Very easy to pull off. Get the soft version from McMaster, with a thicker wall to avoid kinks.

Pete, did you get the silicone tubing you were ordering yet? Maybe you can confirm ID/wall that works well, I'm not near the plane to measure it.

Tygon, which is pvc tubing, is a real PITA to work with. Impossible to remove after a period - I don't recommend it. It also likes to kink in the heat.
Click to expand...

Alex,
The silicone rubber tube sounds good, probably better than the Tygon. I would like to try it, however McMaster thinks the only market in the world is the USA and will not ship overseas. In defense of the Tygon, there are many different types of Tygon tube, I found the Tygon from ACS was very easy to work with. ACS describe it as "ideal for hookup of airspeed pitot and static lines".

Fin
9A Australia
 
Rick_A said:
So is the Tygon as good or better then the Nylo Seal? What's the best way to connect Tygon to the Nylo Seal? I'm OK with the way my steam gauges are connected, it's the connections between the Airspeed-AHRS-AP that would really benefit from using the Tygon.
Click to expand...

Rick,
Can't easily answer if the tygon is better?? than the Nylo Seal. I can say it is easier to work with and in my opinion the finished job looks neater.
Fin
9A
 
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Finley Atherton said:
Alex,
The silicone rubber tube sounds good, probably better than the Tygon. I would like to try it, however McMaster thinks the only market in the world is the USA and will not ship overseas. In defense of the Tygon, there are many different types of Tygon tube, I found the Tygon from ACS was very easy to work with. ACS describe it as "ideal for hookup of airspeed pitot and static lines".

Fin
9A Australia
Click to expand...

Fin, I was not very accurate in my post. Tygon is a trade name, and includes quite a wide range of materials, including silicone. I don't know what the stuff ACS sells is, maybe it is the silicone. PVC tubing has commonly been called Tygon, apparently erroneously.
 
Rick_A said:
What's the best way to connect Tygon to the Nylo Seal? I'm OK with the way my steam gauges are connected, it's the connections between the Airspeed-AHRS-AP that would really benefit from using the Tygon.
Click to expand...

Rick,
Can't fly at the moment so I spent some time looking in the ACS catalog. A way to join the Tygon to the Nylo Seal would be to use a Nylo Seal 268-N connector, AN910 Alum coupling and a AN840 alum hose nipple (or a polyethylene adapter tube to pipe ACS #0700-153).

Fin 9A
 
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Alex,

I got some aftermarket static ports that use the barbed fittings into 1/4 in I.D. flexible line. I did not want to use barbed fittings behind the panel. I don't know what combination you are using, but mine are impossible to pull off once installed. They MUST be cut off. Not very good for ongoing maintenance. I have the good barbed fittings from Spruce, and the good, flexible tubing, I forget where I got it.

The best certified airplane that I remember working on had lightweight flexible hose and AN fittings behind the panel. I want to be able to unscrew the fittings at the instrument, not wrestle with them.
 
Craig said:
Alex,

I got some aftermarket static ports that use the barbed fittings into 1/4 in I.D. flexible line. I did not want to use barbed fittings behind the panel. I don't know what combination you are using, but mine are impossible to pull off once installed. They MUST be cut off. Not very good for ongoing maintenance. I have the good barbed fittings from Spruce, and the good, flexible tubing, I forget where I got it.

The best certified airplane that I remember working on had lightweight flexible hose and AN fittings behind the panel. I want to be able to unscrew the fittings at the instrument, not wrestle with them.
Click to expand...

Craig,
Fair enough point about the inconvenience of removing the hose from the barbed fittings. You will see most of the barbed fittings in my photo in Post # 6 have a single barb. It is easy to slip the ACS Tygon tube off these single barb fittings. The 90 degree fittings on the ASI have 3 barbs and I would have to cut the hose and/or fitting to remove the instrument.

Fin 9A
 
I thought I'd post an update on my solution.

Here's a picture:



I used the 1/4 in. I.D. flexible hose as a kind of manifold.

Notice the barbs coming off the airspeed pitot and static lines (top right in this picture). That was a restriction in my system that I forgot to mention. Those are for the AOA computer. They require the 1/4 in. O.D. rigid tube.

I ended up with good, removable connections at the instruments, and enough flexibility to pull the panel at least a little aft.
 
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