Rev LE End Shock Cord Attachment, Repair and Improvement

[SegelFlieger]

My kite was recently damaged by wind conditions that were too strong for my sail choice that day;  I had become overly anxious to fly a kite that I had built this winter and had been eagerly waiting for an opportunity to fly.

As a result of this mistake, the shock cord that attaches the leading edge rod to the sail, tore the Dacron tab between the two holes in which the cord passes through and is tied in a knot on the backside of the LE.  

I admit that this happened because of a slight design flaw in making a leading edge out of one piece of Dacron and using holes to replace the screen mesh.  In my design I chose not to extend the end tab to the sail, which is how the example LE appeared to be made.

In repairing the damage I also came up with an idea to improve the shock cord attachment to the LE.  I have always been bothered by how the two holes and knot "bunches up" the LE at the end distorting the top edge of the kite as a result.

I wanted to find a reinforcing washer that had two holes in it spaced the same distance as the holes in my LE.  The washer had to be light weight, rigid, have the holes spaced properly, and have a hole diameter to match that of the shock cord.  "Is that too much to expect?" you might ask.  Well I thought so too and was considering making the washers myself... however as I imagined "re-purposing" things that Aren't washers to Be washers I came up with this solution:

This is part of a chain link for a standard #35 drive chain.  Once I recognized that the shape of the outer links might be a solution I found a chain size chart that gave the specifications for a variety of #'d chains.  The #35 had hole spacing (i.e. Pitch) of 3/8" with hole diameter (i.e. Pin diameter) just slightly larger than 1/8".  This was a perfect match for what I had imagined!

So after repairing the tear with two pieces of Dacron (one on each side), using the new washer,  and a banana (carry over from my "You Know You're a Kite Nut When..." post), I made the modification to both sides of the LE:

Items used for the repair.
The repair completed.
The LE is no longer distorted at the ends and the tear that occurred between the two holes will not happen again. 

I plan on adding the washers to my other kite sails.
Hopefully this idea might help some of you as well.
SF

 

 

[Chook]

Nice idea for spreading the load.

Most chains are black steel, so just a heads up about rusting. Even anodized chain has an uncoated internal hole.

[makatakam]

Piece of stiff plastic. Bottle cap would work nicely. Cut with utility knife to any shape you like. Drill two holes. Can be done in the field with a pocker knife. One-third the weight.

[SegelFlieger]

I should have included this information in my post...

Two chain washers weigh 1.7g (.06 oz).

My new kite weighs 230g (8.1 oz) -> rev Mid-vent equiv with two-wrap rev rods; shock cords are not trimmed yet.

The addition of two chain washers will only increase the weight of the the kite defined above by .7%

 

I like the field-fix idea . Considering a tear as I experienced, a bottle cap washer with two holes could allow one to continue to fly; it would support the vertical displacement of the shock cord loop against the remaining Dacron and there would still be plenty of meat left on the horizontal portion of the LE end for the required shock cord tension to the rod end.

Add a pocket knife or multi-tool to the things you should bring along with you for emergencies. I plan to.  Make sure the tool has the equivalent of an awl or pointed knife tip to make the holes. 

Thanks Mark.

SF

[John Barresi]

Have a link for online purchase of those two-hole washers?