So I'm having an argument with a mate about how to properly adjust your trim strap while out on the water..

Where we kite at this time of year the wind can be extremely variable. Its not unusual for the wind to swing between being at the upper limit of the kites wind range down to the lower limit of the kites wind range several times in a session. Im always on the trim strap trying to maintain the perfect trim so that my bar is where I like it with the kite powered up nicely with my elbows only slightly bent.

Here is his interpretations of what the trim strap should be set at vs wind speed based on what he was told by an instructor:



And this is my interpretation based on personal experience (never had lessons):



So, which one is correct? Or are we both doing it wrong?

I like yours better but I think you got the curve back to front and the bottom axis labelled wrong - should be "kite air speed". Oh and "trimmed" not depowered...

I much prefer the term trim to depower. I think you are way over thinking it. Forget wind strength and just adjust at all times to achieve the desired reach, stance, kite height, board edge combination. If feels right then the adjustment is right.

I love these sort of arguments, not really that practical but good to get you thinking about how you might improve your skills. I don't think either of the charts capture all the variables required for it be really useful, other things to consider would be:

* surface state (going flat out on glass is going to require different trim to picking through a break)
* gust range (with a smaller gust range you can afford to be less trimmed)
* effort to fly (flying a 17 in 12 knots is obviously a lot less effort to than a 9 in the same wind state)
* board size (related to the last)
* apparent wind potential (a combo of boar size, effort to fly, surface state, etc. How easy it is to get air moving across the kite)
* angle to apparent wind (depending on your apparent wind potential you go better upwind when perfectly trimmed)

I could go on but I'll give cdog a chance to plot all those for me, then he can hand it over to Laurie to whack into a nice little JS app that I can sit there and twiddle with all day instead of looking at the forecast waiting for the wind to never show up

No worries Dl33ta, Ill be out today doing some field data collection for my trim strap thesis.

Ill have to get back to you with my revised graph later, many numbers to crunch and beers to drink

I do understand that there is many influencing factors that determine trim (mainly personal preference).

The main point that I am trying to argue with mate in question is that in the overall picture, to maintain the same riding position in regards to the bar and a kite that stays in the air one must:
-Trim the kite for less power at the upper end of the wind range of particular kite (To avoid chocking and stalling the kite, and being overpowered)
-And also trim the kite for less power at the bottom end of the wind range of particular kite (Also to avoid choking and stalling the kite)

Or, If I where to follow his advice:
- more wind = trim kite for less power
- less wind = trim kite for more power
- No exceptions

The reason Im trying to argue this is because he struggles in light wind conditions, If the wind dropped off he couldn't get back to the beach if a shark was right up his ass. Meanwhile Im still out sliding around, underpowered but still having fun. Same setup, same kite size, almost the same body weight. He puts its down to riding style but I do believe its his trimming technique.

Anyway Ive already got confirmation from Kamikuza that I'm correct, somewhat. Now to claim my victory!

I agree with over thinking.
But looking at the curve I agree with some trim in really light wind then ibwould have a flat line across the top for the majority then add trim as your getting uncomfortable
We get up and down westerly wind throughout winter.
It's more efficient to use your body position and board edging to control the change in wind conditions. In a 4 hour session might touch the trim twice. Usually when you adjust the trim you are off your edge or leaning forward to reach it meaning your losing ground. When it gets stronger just lean back a bit more.

Hey I said like, not is a confirmed fact. I think once the kite has a certain air speed, it'll be almost impossible to back stall.

And you can trim light wind to minimize back stall too

I find ur graphs confusing without numbers,colours and a legend.


Trim as required to suit the waves and wind dude

Select to expand quote

gcdave said..
I find ur graphs confusing without numbers,colours and a legend.


Trim as required to suit the waves and wind dude

Whoever thought the depower strap could be so advanced...
If its windy, pull the strap.
If its not, let it out.
Tooooo easy.

Select to expand quote

surfingboye said..

gcdave said..
I find ur graphs confusing without numbers,colours and a legend.


Trim as required to suit the waves and wind dude

Whoever thought the depower strap could be so advanced...
If its windy, pull the strap.
If its not, let it out.
Tooooo easy.

If its really not windy, pull the strap.

Always better to understand how and why things work, rather than just follow steps blindly...

Select to expand quote

Kamikuza said..

surfingboye said..

gcdave said..
I find ur graphs confusing without numbers,colours and a legend.


Trim as required to suit the waves and wind dude

Whoever thought the depower strap could be so advanced...
If its windy, pull the strap.
If its not, let it out.
Tooooo easy.

If its really not windy, pull the strap.

Always better to understand how and why things work, rather than just follow steps blindly...

or you could put up a bigger kite.

Then your just gave to trim it again.

I'm still caught up on the labelling of the choke zone. Are you saying that in higher than ideal wind you can make your kite stall (or sit back further) by leaving the trim on maximum power? From my (limited) experience it will fly further up the wind window and give greater bar pressure. I've always trimmed to make the bar pressure more bearable but acknowledge that I'm giving away a slight upwind advantage in doing so. Maybe because I'm only flying larger kites (12,14,17)?

Not necessarily. Maintaining good form, you should go upwind just as well, if not better.

I think "Choke zone kite falls backwards in strong winds" indicates your kite is oversheeted. This shouldn't happen in strong winds. Check your rear line lengths and the knots you tie off on. Sounds like your rear lines are a bit too short. The trim range setting should not have this effect.

I use bar pressure as a gauge as to trim or not trim. If I've pulled the bar right in and the bar pressure is high I use a little trim to reduce the bar pressure and visa versa. Look at the kite, if it's well forward in the window you probably have good trim.

Definitely over thinking.
Until you work out anything better park at 12 when you first head out (in the water not on the beach).
Trim in or out till back lines are just beginning to bow when your bar is fully pushed out. This gives full range of depower at the bar for that mount of wind. After that just follow surfingboye advice. Simples.