Bumper yaw string

Shaun the sheep video notwithstanding, if one were tied to a chair and forced to put up with that over and over, how long do you suppose it would take before you'd go stark ass bleating crazy?

Once upon a long time ago, it was postulated as to how natural wool yarn was less abrasive to glider canopies. I have not data one way or the other, but one could order natural wool or synthetic yarn for their MK#. Most chose natural wool.

I've tested yarns and found synthetic yarn lasts longer. I've also done testing of the MK# yaw strings, holding a curved acrylic surface out the window of my truck, to mimic a glider canopy, so I could view the string from the side. Due to the design of the MK# base, the yarn streams back maintaining the lift and separation imparted by the base, and looks to maintain that separation all the way back not appreciably touching the canopy at all.

With a normally maintained canopy, no scratching. If left parked out, uncovered, and with blowing dust or sand, I'd expect any string or yarn material might cause fine scratches. Loose covers can cause deep scratching.

Yes Thanks Bumper! I too bought a MKIV and am quite happy. Although I think Bumper might be unhappy with me, as I immediately modified it. I had problems with the previous MK II or whatever it might have been, snagging the canopy cleaner microfiber cloth I use, so I ever so carefully rounded the front point and beveled the edge of the plastic. I know what your going to say Bumper, I've completely ruined the aerodynamics of the thing. But I have to say it has stayed on now for at least 4 years with an avg of 200 hrs/yr But alas its now worn out as the yarn is completely unraveled and I had to tie it on the end (yes I am a cheap glider pilot). I was by the way the first one to ask and receive a white one! Do they come with a lifetime warranty

CH Ventus B

On Thursday, December 3, 2015 at 12:51:49 PM UTC, wrote:
Yes Thanks Bumper! I too bought a MKIV and am quite happy. Although I think Bumper might be unhappy with me, as I immediately modified it. I had problems with the previous MK II or whatever it might have been, snagging the canopy cleaner microfiber cloth I use, so I ever so carefully rounded the front point and beveled the edge of the plastic. I know what your going to say Bumper, I've completely ruined the aerodynamics of the thing. But I have to say it has stayed on now for at least 4 years with an avg of 200 hrs/yr But alas its now worn out as the yarn is completely unraveled and I had to tie it on the end (yes I am a cheap glider pilot). I was by the way the first one to ask and receive a white one! Do they come with a lifetime warranty

CH Ventus B

Ahh yes - the perennial issue of whether to tie a knot at the end of the yarn in the Mark IV. I tied a knot right at the end of my last one as it started to unravel a little but it changed the aerodynamics so that the terminal couple of centimeters or so waggled annoyingly. Then I tied a knot about a centimeter from the end and allowed the end to fray to create a little drag and that worked OK. My current one is still as delivered, hasn't unraveled yet and is performing well.