The Hoff bar

[rynhardt]

I'm planning to build my own control bar over the next few months.

The main feature is that there will be rear line trim controls, on the bar itself.

This replaces any kind of above-the-bar or below-the-bar front line trim system.
I like to call it an on-the-bar trim system.

The idea is that you operate the latching mechanism with your thumbs, one on either side.
There is a pulley that provides a 2-to-1 ratio, so a 20cm adjustment on the bar will effect a 40cm adjustment on the rear line.
I've put 4 indents at 5cm intervals, so you get trim adjustments in 10cm increments.
I'm hoping the visual aid of the ball and the position of the button on the bottom of the bar offer enough visual cues to keep the line lengths synchronized.

I think the video demonstrates the principle the best.



Materials used will probably be:

• HDPE sheet, for the latch mechanism, teeth and centre hole.
  Aluminium rod for the pivot points/pulleys.
  Aluminium rectangular tube for the outer casing.
  Some kind of foam for the grip.

Construction should be pretty straight forward. I'll send the HDPE pieces for laser or water cutting. The aluminium bits are easy enough to do with normal hand tools.

There is a fair amount of guesswork involved at this stage.
How easy will it be to operate? Will it be strong enough? Will it tolerate sand and how do I clean it? Are the two independent sides (left and right) easy enough to keep synchronised? Will I get strange comments on the beach?

As always, the best way to find out is to build it and see..

[plummet]

Very interesting.

I see a couple of potential safety issues you might want to consider.

It seems like you need to adjust both side indepentantly. That could lead to one side being shorter than the other leading to a potential death looping situation.

The system needs to be somehow free draining of sand. If the mechanisim clogs up it wont work.

Lastly any line that moves across pullies/sliders wears out quickly. is there any easy method to change out the line?

[plummet]

oh another thought. Kites with little bar pressure might not have enough pressure to pull the line out thus causing a line clog on the id of the bar. It may require full bar in to get enough pressure to trim. Also kites with high bar pressu

[borist]

It seems like you need to adjust both side indepentantly. That could lead to one side being shorter than the other leading to a potential death looping situation.

this would be my main worry as well.

[downunder]

Awesome idea!

I like your 3D skills as well.

On the bar note, I do not ride on the ocean, so sand is not a problem for me. Salt is. Always rinsed my bar with fresh water but the salt deposits inside of my Airush Smartbar bar is huge. Absolutely no way to extend the bar any more, impossible to press this two buttons.
So yeah, I like my kites and take all the care I can, but loosing battle with a salt.

D.

[KerryBara]

Awesome Rynhardt!!!

It looks like you will need to dismantle your center line to open it up and adjust? This system needs to be adjustable on the beach right?

Isn't there a way you either adjust the position of the pulley or pull the string through and attach without dismantling the bar?

Looks great

[rynhardt]

Anyhoo, thanks for all the other comments so far.

For the sand issue, I'm thinking along the lines of a semi open cage for the grip, so that you can flush it clean easily.
As for the death loop scenario, in this case you would still be able to steer, and still be able to depower, it just that your bar will be at an angle. I think death loops happen because the bar is typically snagged on something so you cannot steer or depower.

[rynhardt]

@kerry: not sure if I follow you completely. The idea of this is so you can adjust trim at any time, without having to reach up or down to the existing front line trim systems.

In terms of attaching your front lines, you would need to disconnect the chicken loop assembly, and thread the depower/front line trim/front line mini-fifth through the bar, same as any other bar, if that's what you're asking.

[rynhardt]

@plummet: you're right about the low bar pressure issue. Not enough pressure and you cannot extend the lines without it possibly kinking.
It may require you to power up and trim at the same time.

I will probably use leader lines from the bar to a knot/ring at the same distance as the front line Y, where your flying lines will connect. Similar to other bars in that respect, so you can just change out these lines at the bar end.

thanks, good points!

[BWD]

Simpler is better.
I have a version for one line, one cleat, really relies on one key part.
I think it might be good -if the ergonomics feel ok....
My version: 1:1, single cleat/stopper in middle, outside the bar, single continuous line forms both rear leaders.