# Alternate To 1/4 Inch Pitot/Static Tube

Discussion in 'Instruments / Avionics / Electrical System' started by Toobuilder, Oct 2, 2016.

1. Oct 2, 2016

### Toobuilder

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For those looking to save every gram or if you have space limitations, I just installed these neat push lock connectors and 1/8 tube from MSC Industrial Supply.

Shown for comparison is the ubiqitous 1/4 tube.

The tube is a dime per foot and the fittings only a couple of bucks each.

The link to the fitting is here:

They are available in a wide variety of sizes and the tubing is too.

I've never dealt with MSC before but they are fantastic. I'll be using them a bunch in the future.

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2. Oct 2, 2016

### TerryM76

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SMC is another source for these type of fittings. I was sold on these about 20 years ago while working as a production technician for TRW. I don't think you will have any significant weight savings due to the metal used in the connectors but I plan on replacing the instrument fittings and tubing in my plane with this type during the condition inspection.

Terry

3. Oct 2, 2016

### Toobuilder

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The weight savings comment was slightly tongue in cheek, but the difference between 50 feet of 1/4 vs 1/8 tube is certainly there. And not to mention the smaller stuff is a LOT easier to string all over the airplane!

Interestingly, these high quality Parker fittings were quite a bit cheaper than the plastic Home Depot items they replaced.

4. Oct 2, 2016

### Tom Nalevanko

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Nice; certainly the way to go; might even be able to find smaller.

Blue skies,

Tom

5. Oct 2, 2016

### Toobuilder

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There has been at least some discussion about water intrusion and the inability of the smaller tubes to drain due to surface tension. Not sure how much of an issue that really is, but just in case I'm going to make sure the vertical rise from the static ports to the top of the fuselage will be 1/4, with the transition to the 1/8 at the T fitting.

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6. Oct 2, 2016

### Dana

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Those fittings have become standard in the automatic machinery world, where most things are driven by pneumatic cylinders. McMaster-Carr has them as well. You can even get them in all plastic if you really want to save ounces...

My pitot line is 1/4" which is what the builder installed, but I do have a two sided push in fitting like that to join the tubes in the wing root so the wing can be removed. When I added a static line I used 1/8".

Dana

7. Oct 3, 2016

### fredoyster

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Toobuilder, have you had zero problems with leaks using the push connectors?

8. Oct 3, 2016

### Dana

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I've never had trouble with them in all the years I've used them on machinery (or planes). They're rated to over 100 psi, far more than a pitot system. You do have to use the right tubing, polyethylene or hard polyurethane; the fitting won't grip the common soft vinyl tubing adequately and it'll pull out.

Dana

9. Oct 3, 2016

### Toobuilder

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I have not flown with it yet, but like Dana says, they are rated for hundreds of PSI and I cant pull the tube out of the fitting unless I push the release collar.

That said, there are some "off brand" fittings sold right along with these that are a bit cheaper, but I don't know how well they work.

10. Oct 4, 2016

### 12notes

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I use these at work as well. If you need to use more flexible tubing, you can connect it through a 2-way barbed coupler to a short piece of stiffer tubing right which the fitting will hold.

I just looked on MSC, they want $9-14 for one of the couplers! It's just a small piece of plastic. Grainger is cheaper, probably not the cheapest @$6-8 for 10.

Grainger couplers

11. Oct 7, 2016

### cluttonfred

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For what it's worth, if you wanted to use the MSC or other quick-connect fittings and colored tubing but not make the switch to 1/8", they do have them all in 1/4" as well.

12. Oct 7, 2016

### StarJar

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I never knew 1/8 tube could be used. Are you sure the size is OK. It has about 1/4 of the internal x-section of 1/4" tube.
I like the small size. There is others doing it?

13. Oct 7, 2016

### Toobuilder

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Yes, in fact some of the new glass avionics use the 1/8 stuff. I think the new Garmin G5 instrument uses these connectors in the small size. That's where I stole the idea from in fact. And it turns out many of the RV guys have been doing it for years.

My only "breakthrough" (and the purpose of this thread) is that I found a supplier - and it's dirt cheap to boot!

And yes, the tube is available in a wide range of sizes (including smaller than 1/8) and a rainbow of colors, with the corresponding pushlock connectors to go with them.

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14. Oct 7, 2016

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