New Presentation - Working with Air Lines

[OHM Ω http://aviation.derosaweb.net]

I put together a short presentation on how I work with, and repair, air lines in gliders. It might be useful to you. Maybe not. Don't know quite yet.

If you find something to add, correct, or just to make a comment, please let me know.

http://aviation.derosaweb.net/presentations#airlines

Enjoy, John OHM Ω

PS - Most of the "Airline" presentation information came from, and was removed from, my "Wiring" presentation - http://aviation.derosaweb.net/presentations#wiring

[Matt Herron Jr.]

On Saturday, March 2, 2019 at 11:26:45 AM UTC-8, OHM Ω http://aviation.derosaweb.net wrote:
> I put together a short presentation on how I work with, and repair, air lines in gliders. It might be useful to you. Maybe not. Don't know quite yet.
>
> If you find something to add, correct, or just to make a comment, please let me know.
>
> http://aviation.derosaweb.net/presentations#airlines
>
> Enjoy, John OHM Ω
>
> PS - Most of the "Airline" presentation information came from, and was removed from, my "Wiring" presentation - http://aviation.derosaweb.net/presentations#wiring

Nice presentation, thanks for putting it together. One comment, the use of zip ties for attaching tubing is not usually recommended, as they can leak.. The tubing gets scrunched up near the head of the zip tie and can form slow leaks. Pinch style hose clamps can work well, as they provide an even "squeeze" all the way around.

Matt

[Richard Pfiffner[_2_]]

On Saturday, March 2, 2019 at 11:26:45 AM UTC-8, OHM Ω http://aviation.derosaweb.net wrote:
> I put together a short presentation on how I work with, and repair, air lines in gliders. It might be useful to you. Maybe not. Don't know quite yet.
>
> If you find something to add, correct, or just to make a comment, please let me know.
>
> http://aviation.derosaweb.net/presentations#airlines
>
> Enjoy, John OHM Ω
>
> PS - Most of the "Airline" presentation information came from, and was removed from, my "Wiring" presentation - http://aviation.derosaweb.net/presentations#wiring

If you have good tubing the Tie wraps and or cast ring are not needed. This is very low pressure.

Richard
www.craggyaero.com

[Charles Longley]

Good article! I don’t like the castration rings because they erode quickly. I use the small black tie wraps from this vendor- https://tiewraps..com/stainlesstooth_twpage.html

[[email protected]]

On Sunday, March 3, 2019 at 3:08:50 PM UTC, Charles Longley wrote:
> Good article! I don’t like the castration rings because they erode quickly. I use the small black tie wraps from this vendor- https://tiewraps.com/stainlesstooth_twpage.html

As Matt said, tie wraps are not the best idea as they are known to sometimes cause leaks by pinching if they are very tight and are useless for grip if they are loose. On instruments and metal T-pieces etc nothing additional is usually needed to keep tubes in place. Alternatively use a couple of rounds of locking wire which gives an even squeeze. Those little rubber rings have no effect IMHO except on soft silicone tubing.

On plastic T-pieces which may have a little moulding flashing then the best way I know to make a good seal and help with location is (after removing as much flashing as possible) to use some soft contact adhesive like Evo-Stik. It is still to remove tubes and pick off adhesive remnants when necessary.

BTW we had a brand new glider delivered from the factory with the TE tube disconnected from its fitting in the fin. It had been held on by a tie wrap..

Another thing I think is important is to support any loops of free tubing and generally immobilize tubing as much as possible to prevent pressure changes from the tubing flopping about in turbulence or under G forces on thermal entry pull-ups.

[[email protected]]

I like these clamps. This item is 8.5 mm, but they are available in many other sizes.

https://www.amazon.com/Wingsmoto-Tubing-Spring-Motorcycle-Scooter/dp/B012MBHEHQ/ref=sr_1_19?crid=25WE6UMZD2W5G&keywords=tubing+spring+clips+clamps&qid=1551632765&s=gateway&sprefix=spring+tubing+clamps%2Caps%2C197&sr=8-19

[OHM Ω http://aviation.derosaweb.net]

Thanks the comments. This is why I ask RAS to take a look at my ravings.

It seems the general current consensus is that the air lines do not need any type of constricting band at barbed fittings. And might even be counter-productive.

So I updated my presentation to that effect. Who knows - maybe this dictum will be reversed upon future consideration.

http://aviation.derosaweb.net/presentations#airlines

- John OHM Ω

[[email protected]]

John- Good presentation. Glad to see you recommended Lee Kuhlke's Soaring Magazine article on diagnosing air leaks. Mike Borgelt (Borgelt Instruments) also wrote a nice guide on the subject. I have a pdf if anybody wants it.

One thing I discovered several years ago is a neat way to reduce the number of T connections in the static line system. As you know, there can be multiple static ports, and many instruments require a static source. I incorporated a small plastic aquarium manifold to allow individual plumbing lines for each port and instrument. It really cleaned up and simplified the routing of lines, as well as reduced the number of T junctions, each of which just added to the potential number of leaks.


https://www.amazon.com/uxcell-Plastic-Aquarium-Manifold-Divider/dp/B01M0FWCX4/ref=sr_1_28?crid=19HXPUATNZXAF&keywords=aquarium+manifold&qid=1551644008&s=gateway&sprefix=aquarium+manifold%2Caps%2C202&sr=8-28

This one has one input and six outlets, but they also come in 4, 8, 12. Some are metal, but the plastic one (above) has been adequate for my needs. Note that the inlet is a larger diameter, so some sort of adapter may be necessary.

[Richard Pfiffner[_2_]]

On Sunday, March 3, 2019 at 10:30:54 AM UTC-8, OHM Ω http://aviation.derosaweb.net wrote:
> Thanks the comments. This is why I ask RAS to take a look at my ravings.
>
> It seems the general current consensus is that the air lines do not need any type of constricting band at barbed fittings. And might even be counter-productive.
>
> So I updated my presentation to that effect. Who knows - maybe this dictum will be reversed upon future consideration.
>
> http://aviation.derosaweb.net/presentations#airlines
>
> - John OHM Ω

John,

Great article seeyou in Nephi.

Richard
www.craggyaero.com