Foil kite tuning paraglider style with laser and weird results

[PugetSoundKiter]

…Any thoughts?

Guessing less tension because:
- Wing tip chord is less = less lift
- Wing tip cells are narrower = closer bridles
- Wing tip bridles/span are denser = closer bridles

[Herman]

I probably did not explain myself well, lazy brain. I was actually asking for thoughts regarding the bridle angles see attached.

Bridle tension will be a function of lift x the inverse of the cosine of the angle between direction of lift and the bridle line. See attachment (literally, it is my artist’s impression of an attachment)! I don’t have much of a feel for how large or small these angles may be and, was interested in any observations regarding this angle. Obviously these angles cannot be too big or the bridle would overcome cell pressure and collapse the cell.

PS there is a mistake in the photo T= L / Cos a

[derek440]

To add more info as I find it, interestingly Ozone have created a page all about tuning the R1 race kite. I have also heard through other racers that Flysurfer are also doing lots of work on tuning but not publishing anything. Ozone's info is here https://ozonekites.com/sports/racing/r1-pit-stop/

Not much news in the post from ozone apart from one gem about how to shorten A Main 1 lines (AR1 on an ozone), this confirms for me that the R1 is primarily suffering from a similar issue which is that they slow down over time and mostly due to A Main 1/AR1 getting longer relative to the rest of the bridle which is shrinking. The gem of info is that rather than splicing a new line they recommend shortening AR1 by taking the mixer off and doing a double loop of AR1 around the top mixer line that connects A level effectively shortening A bridle and every point attached through it A1-A8. They also recommend short mixer test and zero the mixer. So what they are saying is zero the bridle and zero the mixer which probabl needs B/C/K longer and/or A shorter.

Reassuringly this is pretty much exactly what we have found with the Booms and have adjusted. The two key changes I have been making/recommending on most Booms as they get older are shorten A Main 1 relative to A Main 2 or lengthen A Main 2 for the same effect. And also zero your mixer by shortening A or lengthening B/C.

And with the laser measuring rig I can now check all of these changes before and after and map the shape of the full bridle/kite to ensure they make the right shape and that its back close to factory settings. RE the laser rig, one of the guys from our club made up a sliding frame for the laser and 3d printed a mount for the weight at the mixer end with a laser reflector plate at the mixer connection point and also a laser holder with kite line knot holder at the canopy end on a slider. Here are some pics that should make more sense than the words, there are also youtube vids copied above in this link to show a similar rig.