First, a bit of history. Sometime during the mid-90s, there was a long discussion on the Hang Gliding Mailing List regarding the use of relief tubes and how to keep them from falling off. This discussion dragged on for quite some time. At last, determined to offer some useful suggestions on this important subject, I posted the following contribution. For some unexplained reason, the discussion ground to an abrupt halt the very next day.

The Famous Relief Tube Post
  (c) Paul Gazis, 2009, alas

Handy tools

One of the biggest challenges facing serious cross country pilots is how to answer the call of nature during a long flight. For female pilots, the alternatives are limited. Male pilots can take advantage of an invention known as a ‘relief tube’. These devices -- known by a variety of other names that may not be appropriate for a public forum such as this -- consist of a long tube attached to a handy elastic sleeve that can be unrolled to provide a snug and water-tight fit. Unfortunately, during the stress and turmoil of a challenging flight, relief tubes have been known to come loose, with unfortunate consequences. For this reason, a wise pilot may wish to take one of the following precautions to improve the quality of his attachment.

1) Glue
For obvious reasons, this glue must not be soluble in water. But for equally obvious reasons, it must be soluble in something.
Advantages: Simple, straightforward, and comparatively inexpensive.
Disadvantages: Messy and inconvenient. Also, some pilots complain that this method can reduce sensitivity and make flight less ‘spontaneous’.

2) Sutures
Used alone or in conjunction with other methods, this technique can provide a secure attachment that is unlikely to fail even in severe turbulence.
Advantages: Robust, sturdy, and reliable.
Disadvantages: Requires trained medical personnel to apply. Repeated use can lead to inflammation.

3) Machining
Examine your attachment point. You will notice that it contains a small orifice. Drill and tap this orifice to a depth of approximately ˝". Machine a brass fitting of the appropriate diameter and fit this with a o-ring and sealant. Note: to avoid a repetition of the Challenger disaster, this o-ring should be suitable for use at low-temperatures and high altitudes.
Advantages: The slick ‘high-tech’ appearance makes this method attractive to many modern pilots.
Disadvantages: Complicated, expensive, and can be prone to failure in dusty environments. Also, care must be taken to avoid cross-threading.

4) Welding
Advantages: Tough and durable, this method can be applied by unskilled operators using equipment that can be found in the field.
Disadvantages: This method is not for everyone. But it shows a profound level of commitment -- the type of commitment that separates truly great pilots from the common run of humanity.



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Last modified: 25 September 2009