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Bungee/endcap Modifications

Posted: Thu, Sep 15 2011, 05:47 PM
by makatakam
For anyone who's's the final version(s) of my modifications for endcap to bungee to sail connections.

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The components, from left to right:
1. Spar
2. Bungee, knotted end
3. Endcap
4. Sail
5. Screw cover with hinged cap
6. Nylon washer
7. Bungee, flamed end

The assembly sequence:
1. Disconnect the bridle from the endcaps and the bungee from the sail and the endcaps. Put the washers in your spare parts collection.

2. Cut bungee to length. Flame and roll each end between your fingers to keep it about the same in diameter. Four inches should be more than enough. I use two to two-and-a half inches = a very tight sail. I recommend starting with more than necessary. You can always adjust the tightness by shortening it. Its a trial & error process. After you've done a few, you'll develop a feel for how long it should be. Tie an overhand knot as close to the end as possible. Draw the knot as tight as it can be with pliers. Trim the excess and flame the end.

3. Drill a 5/32" hole in the endcap through the end that goes over the spar into the triangular transverse hole where the bungee and bridle are usually attached, but not all the way through the end of the cap. Remove any debris and flashing caused by the drilling process. The hole doesn't need to centered. Push the un-knotted end of the bungee into the cap and out one side of the triangular area. Pull the knot into the endcap as far as it will go. The spar will go into the cap and over the knot during kite set-up. In other words, the knot inside the endcap should end up inside the spar tube when you assemble the kite.

4. Push end of bungee through hole in sail. From the back if you want the screw cap in front, or from front if you want it to end up in back. I burn new holes in the sail to accommodate the bungee. (See photos for locations) Push bungee through bottom of screw cover and through the nylon washer. At this point you can make approximate adjustments to the length of the bungee. (Hint: you can always shorten the bungee, but you can't make it longer.) Flame the end of the bungee while holding it vertically and let it burn until it forms a nice "mushroom" shape and blow out the flame.

5. Assemble kite and shorten bungees by cutting at the end inside the screw cap, symmetrically, all around until you're satisfied with the tension on the sail. Snap the screw cover caps shut, reconnect the bridle, and you're done.

6. Optionally, you can use small steel chain links to crimp the end of the bungee at the screw cover end. You can find these at craft stores in the jewelry making aisle. If you prefer this option, the nylon washer is not used. Use pliers to crimp the ring at the desired location, trim the excess bungee, flame what sticks out and close the cap over it while it's still hot to flatten it so it fits under the cap.

Re: Bungee/endcap Modifications

Posted: Thu, Sep 15 2011, 07:24 PM
by Mike
It makes for a very neat appearance. Does it reduce snagging when flying like LaMasters?

Re: Bungee/endcap Modifications

Posted: Thu, Sep 15 2011, 08:09 PM
by Darkspark
It definitely looks nice and clean. I would like to see how it performs after a couple weeks of use. And if the screw cap holds under stronger winds. Nice work.

Re: Bungee/endcap Modifications

Posted: Fri, Sep 16 2011, 02:24 AM
by makatakam
Several other variations of this mod have failed repeatedly, but the two methods described have held up with zero failure. I had multiple versions on the same rev, symmetrically located, and these two variations have held for nearly a month (20+ hours of flight time, if that means anything). I don't flail as much as LeMaster. I've also tested the connection by pulling with pliers. The sail will tear before these two will fail, so I don't recommend making them very tight if you still crash every once in a while like I do. I use braided dacron at the top of the vertical spars instead of bungee to bring the ends of the endcaps closer to flush with the leading edge and this makes crashes less forgiving.

There is a considerable reduction in tip snags; most relaease with a few tugs on the line. The only ones that persist are those which catch the edge of the endcaps. I think if the edges of the endcaps were bevelled, as much as 90% of line snags would become ancient history.

I'm still not sure whether the bungee should come out of the sail on the front or back side of the sail. If anyone can help with suggestions and the reasoning behind them, I would appreciate your input very much.