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Replacing Wills Wing U-2 (Litestream) side flying wires
By Everard Cunion, April 2019
Firstly, I have no connection with Wills Wing other than as a user of some of their products. Secondly, this article must be read in conjunction with the U-2 manual, freely downloadable from the Wills Wing web site.
I describe only the control frame corner bracket fittings that must be disassembled to fit the wires. The attachments of other end of the wires, to the crosstube/leading edge junctions, are straight forward. The diagram on page 53 of the manual is titled U2 S2 Litestream Control Bar Assy, so I assume that my observations here apply equally to changing the wires on the Wills Wing Sport 2 and any other glider using the Litestream control frame.
The manual is not particularly clear about this, in my opinion. The thin plastic washers each side of the VB pulley are not even shown in the diagram in the manual (page 53).
The little steel tube (referred to in the manual as a bushing) with serrated (knurled) end, housed snugly in the black plastic end fitting, is removed from rear to front, that is, upwards and towards you in this photo. Only the front part is knurled. The serrations (discernible in this photo) help it grip the black plastic.
I used the blunt (back) end of a 5/16th inch drill butted against the other side of the little steel tube (underneath in the photo) and a hammer. (I will buy another drill next time I go to the hardware store.) Use a mallet, if you have one, to avoid sacrificing the drill (or the drill bit, as some say).
The bottom side wires are retained by a lightly press fit bushing. This bushing is best removed with a special stepped drift, by pushing it out from the rear.
— from the manual, page 41 (July 2007 — third edition)
“Say, Pal, ya got a special stepped drift I can borrow? I need to change my side wires.”
(Me, after patting all my pockets while eyeing the interloper warily…) “Fresh out.”
Watch out: The little steel tube shot out and I spent a while looking for it among the grass and weeds where I carried out the work. Don’t lose your bushing in the bushes.
In this photo, you might just make out the thin plastic washers each side of the pulley (above and below it in this photo). The pulley is a doughnut shaped metal ring. I assume the plastic washers are PTFE or a similarly low-friction material.
The little steel tube with its knurled front end, to the right of the ball lock pin in my drawing, must be re-inserted with the following all in place between the black plastic lugs (sticking downwards in my drawing):
- Thin plastic washer
- Metal pulley ring
- Second thin plastic washer
- Cable tang (of the new cable)
I used a screwdriver poked in through the lot, kind of stirred around to align the parts, to get them lined up enough to push the little steel tube back in. As stated in the manual, which refers to it as a bushing, the tube goes in from the front, so the knurled end is the last to go inside the black plastic. I used a piece of wood on the tube end to protect it from the hammer, but for the last millimetre or so I had to dispense with the wood to get it all the way in.
I omitted the VB chord from the drawing for clarity. (OK, I forgot it!)
The port (left) side assembly is similar, but without the additional complication of the pulley and its washers. It has a similar shaped plastic spacer instead.
As you might have spotted, I tie the ball lock pins to the side flying wires with lengths of thin chord to prevent losing them.
Related
Rigging a Wills Wing 145 U-2 flat on the ground
External link
Wills Wing web site, from which you can download the U-2 manual
Hang Gliding History 