Dirky,

I have left the most difficult component of the pipe launcher for last. The pictures and text will take me 3 times as long to present, as it did for me to make the piece. I tried using different release shackles but rejected them. The cleanest, neatest way I found to do this piece, which satisfied my standards of (1) being saltwater resistant, (2) made from elements which are very unlikely to snag a line, (3) easily replaced if barnacles growth occurs, (4) simple to make, and (5) strong enough to resist an accidental hot launch (while the kite is shackled to the pipe). Here are some self explanatory pictures to consult while you make the project. I will give an explanation about the key parts later. The numbers are the distance in inches between the different components. The parts are labeled (not spelled correctly, though). The 2 screws are ¾ inch stainless steel. The bumper is a cane bottom stop. This keeps the kite from sustaining damage from bumping into the end of the launcher, as the kite bobs around. The line is old spectra kite line. The size of the drill holes are not critical but the one on the bottom of the breech is smaller than the one on the top too preserve as much strength as possible in the CPVC.

Here is picture of the cane stop bumper, not shown in the previous 3 pictures. The second pic shows the kite line which will be fed through all the other sections of ¾ CPVC pipe (about 85’), using a small dowel as a weight. You will make a large magicians wand. The third pic shows the position of one of the 2 anchors ( a net bag with about 25 pounds of rock). This anchor will be repositioned according to wind direction. At times, it can be dragged by the kite into a self-centering position by wind gusts and directional changes. (more later).

Opps, here is the pic of the safety in it's storage position (hole that screw fits into). It is hard to get the pictures in order, since I have to download them in reverse order. The device looks like this when it "armed" and ready for the kiter to unstrap the kitebar, and then, free the lines with an upward jerk, and then, pull the release rod, to let the kite drift downwind, in preparation for the self launch. The safety is left on for extrasecurity while the kiter walks out his lines and sets them in the slits in the floats, to prepare the launch set up. Also, you can put the lock on in order to attend to things on shore...like friends arriving (you can put your kite launch on hold while you launch them..nice thing to do for friends).

Here are 2 pics of the details of the internal slide piece, the breech handle, and the safety snap. I will cover the construction of each piece later. Right now, you may need some orientation.

I should explain the way the safety piece works. When the safety is clipped in place the screw goes through the hole in the 3/4" CPVC outer pipe, and, by sticking down behind the inner slide tube, prevents the internal slide tube from moving back far enough to release the loop on the 2 foot long piece of kiteline that goes to the kite's pump leash webbing.

Now, for a change of pace, I will show some pictures of the actual construction of the 1/2" CPVC inner slide tube. Hopefully they are self-explanatory. Oh yeah, be sure to get a PVC tube cutter as shown in the picture. Sawing PVC with a hack saw does not result in clean cuts.

continued:

After the "V" cuts are made, the area for about an inch or so around the "V" cut needs to be gently heated (like you roast a marsh mallow), but not burned....and done in a WELL VENTILLATED area (fumes from PVC are toxic). When the plastic is softened, get a pair of pliers and crush the ends together, and place it under cold water to harden it up. Then, sand the end to achieve a smooth, pointed end, like in the picture...even more of a bevel would be better. The beveled end is necessary to snag and separate the kite string loop, during the placement of the loop. This will become more apparent, later.

Here is a picture of the slide tube ready to be positioned inside the 3/4" CPVC outer tube. The string is attached at the back of the slide piece, through 2 holes. The screw is positioned here to show you where it will go after the slide tube is inserted. The screw will go first through a hole in the 2 1/2" long, Sch 20 thinwall PVC Breech Handle piece, which is a larger hole than the one in the inner slide tube. The screw should not bind in the larger hole in the 3/4" outer pipe, but should tighten firmly in the small hole in the slide tube. If this is done, the tube will loosely slide, and the screw will act as a guide in the outer tube slot, as the breech handle is used to position the inner slide tube.

Now for the construction of the slotted and drilled outer tube, inside of which the 1/2" CPVC slide tube will be positioned, to complete the release mechanism. Procede by marking the 2 feet long 3/4 CPVC tube as shown in the picture: Starting at the front end (toward the kite):

(1) Measure 4 &1/2" from the front end to the first mark, where a 3/8" hole will be drilled in the top of the pipe, and a 1/4' hole will be drilled in the bottom of the pipe (not shown).

(2) Measure 4" from that hole and draw a straight line indicating where the slot will be drilled, sawed and sanded. (4" slot)

(3) Then measure 4" from the end of the slot to where a 1/8" hole will be drilled, and used to position the safety, when needed.(safety)

(4) Then measure 4 & 1/2" from that hole to where a 1/8" hole will be drilled, to be used for the storage of the safety clip, when not in use.(store)

Here is how to cut the slot: First drill a series of 1/4" holes, then saw and then sand the slot smooth. Try to make it straight and not too wavy. Then drill the other 1/4" holes for the safety and its storage position. Then drill the bottom hole for the kitestring loop to go through. Then, drill 2 small holes on the sides of the larger hole. This is done to allow you to position the kite string loop more easily. This will be illustrated in the next post.

This series of pictures shows the loop end of the 2 foot long kite string, which is attached to the pump lease webbing on the kite, and which runs from the kite to the release mechanism. This kite string ("temporary retainer string" would be a good name for it) stays attached to the kite, much like a 5th line does. The pictures show the loop, as it is poked up through the bottom hole and then through the top hole, and then positioned with your fingers as shown in the second picture, such that the internal slide tube will spread out the loop, and go through the center of the loop. It is important that the slide does not just push the string aside. Some care must be taken at this step, or else the loop will not slip completely around the internal slide tube and retain the kite. The small knotted pull string on the top of the loop makes it easy to feed the string up through the 2 holes. The side notches make it easy to spread out the loop, after it is pulled up through the holes. I might suggest that, where the slot meets the big hole, you should file off the sharp corners. This will prevent the 1/2" stainless steel screw from accidently locking into the notch, if, by chance you rotate the breech handle up or down while positioning the loop. Play around with the assembled piece, and make sure every thing slides easily and does not bind or jam. The spectra kite string will work perfectly with these tube diameters, and give just enough friction to eliminate slop in the system, but not so much friction as to make the sliding action difficult.