Power Kite Forum

depower bar for a fixed bridle kite?

frefel - 15-6-2009 at 09:17 PM

I'm confused. I bought a 4m HQ Scout recently thinking that it was depowerable from the description of the bar. Obviously it is not but I am enjoying the kite anyway and although my primary interest is kiting on the water I think I'm going to learn a lot with this kite on land. Then I run into this:
http://www.powerkiteshop.com/accessories/ozonesamuraicontrol...
The suggestion here is that this bar will make any 4 line foil depowerable. Can that be or is it just that it can be used on any 4 line kite without necessarily acting as a depower bar? If the latter what will happen to the kite when the bar is pushed or pulled hooked in relative to the chicken loop?

lad - 15-6-2009 at 09:36 PM

I guess you missed
this one!

(It's already discussed here too)

jaymzmn - 15-6-2009 at 10:28 PM

I flew a Scout 4m for ages...fantastic kite...

awindofchange - 15-6-2009 at 11:04 PM

You are being misled, the link you provided is not to convert a fixed bridle kite to a depowerable kite but just Ozone's version of the same thing that you have. Your Scout actually comes with a crossover bar which IMO is a better setup and gives the kite much more control than the Ozone 4 line kite bar.

Changing a kite from fixed bridle to depower takes much more than just a control bar. You have to do modifications to the bridles as well which doesn't always work well with some kites and their designs.

Depower is a different animal than fixed bridled kites. There is so much more design and technical challenges in a Depower kite - thus the reason they are quite a bit more money than the standard fixed bridled kites.

acampbell - 16-6-2009 at 05:13 AM

Yeah, this confuses a lot of people at first. Here is a simple schematic of a de-power kite...

http://www.coastalwindsports.com/servlet/the-De-dsh-power-Ki...

...compared to a simple fixed bridle kite on a standard control bar shown below. In this rig, the kite bridle is fixed and the angle of attack (AoA) cannot change. The brake lines run to a pulley at the center of the bar, forming triangles with the power lines at the outside of the bar. When you move the bar to steer the kite, the geometry of the triangles change and have the effect of pulling on the brake line in the direction of the turn...

FoilFixedBridleControlBar.jpg - 32kB

BeamerBob - 16-6-2009 at 05:47 AM

Quote:
Originally posted by frefel
I'm confused. I bought a 4m HQ Scout recently thinking that it was depowerable from the description of the bar. Obviously it is not but I am enjoying the kite anyway and although my primary interest is kiting on the water I think I'm going to learn a lot with this kite on land. Then I run into this:
http://www.powerkiteshop.com/accessories/ozonesamuraicontrol...
The suggestion here is that this bar will make any 4 line foil depowerable. Can that be or is it just that it can be used on any 4 line kite without necessarily acting as a depower bar? If the latter what will happen to the kite when the bar is pushed or pulled hooked in relative to the chicken loop?


the only place I could find mention of depower on that link was that it uses Ozone's "depower loop". That is just how you hook the bar system to your harness but probably wasn't intended to imply the bar provided depower to a fixed bridles kite.

frefel - 16-6-2009 at 02:03 PM

Thanks for the responses but I'm just as confused:

BeamerBob - From description: "Ozone Four Line Safety Fixed Bridle Traction Composite Control Bar " and "4-line composite control bar excellent for use with the Ozone Samurai, Cult, Flow, Quattro, Riot, and Haka as well as any other four-line fixed bridle power kite". Doesn't fixed bridle suggest non depowerabele? And why would they call it a depower loop if it didn't do that? From picture: looks to me like the bar travels over the chicken loop rope passing through it and connected to 2 of the 4 kite lines, just like my Slingshot bar for my LEI. What would that accomplish for "any 4 line foil kite" ie. not designed to be depowerable or am I wrong about the chicken loop and bar independence?

AWindofChange - I agree that you shouldn't be able to make any fixed bridle kite depowerable by just pulling differently on the lines. My Scout control bar has all 4 lines connected to the bar itself and the harness loop is also on the bar. When a gust hits I can only fly it up or to the side but not depower it. The Crossover aspect of it seems to act only as a means to hold the shape of the kite as ACampbell mentions.

Lad - so that link looks like and describes a similar if not identical bar. I don't understand your point? I would also appreciate a link to the previous discussion you mentioned if you don't mind.

In short it appears to me, based on the description and the picture, that the Ozone bar is fundamentally different than my Scout bar and resembles a true depower kite bar. When they say use on "any 4 line kite" do they really mean "any 4 line depowerable kite".. If so I'd say it's a gross misrepresentation.

awindofchange - 16-6-2009 at 04:06 PM

The bar shown in your link will work on any 4 line "fixed bridle" kite. With some modifications you may be able to use it on a depowerable kite but you would not have a power adjuster strap (or cam cleat) to set the angle of attack properly. You would also need to connect the depowerable kite up differently than the fixed bridle kites. You could do the exact same with your Scout bar if you wanted to do some modifications.

You can not depower your Scout on the side of the window because the Scout is NOT a depowerable kite. It is a fixed bridle kite set up on a control bar. On The Scout crossover bar - the bridle actually holds the shape of the kite, not the bar or crossover setup. The crossover setup allows you to pull both the top (right) and bottom (left) lines when you turn (or visa versa), giving the kite better response and tighter turns with less loss of power through the turns. The Crossover bar only improves turning and overall control, the fixed bridle is what holds the kite in shape and is the reason you are not able to depower it.

A bridled depowerable kite is going to be quite different than your LEI. A Depowerable kite such as the Frenzy or Flysurfer will have a complex bridle setup on the sail itself with pulley's or multiple of pulleys that will allow you to actively change the entire curvature of the sail during flight by sheeting the bar in and out - thus powering up or depowering the kite while you fly - in addition to the depower strap which will let you set the angle of attack of the sail. You can not do this on a fixed bridle kite, the sail is the same curvature at all times. You can only change the angle of attack - the sail (and the power of the kite) will be constant all the time.

The Depower loop is just the loop at the end of the center line with the safety release - this can be added to any bar or even handles (with a strop)....but it still does not make the kite a depowerable kite. You are just using the same loop as the depowerable kites use but you are using it on a fixed bridled kite control bar.

By running the depower line through the center of the bar, you can control the angle of attack of the sail by moving the bar up and down the depower line (chicken line). This only changes angle of attack - the same thing your power adjuster strap does on your LEI, it does not power or depower the kite. Sliding the bar up and down the chicken line is the same thing as rotating your control handles forward or backwards. Sliding the bar out will pull the brake lines (by loosening the top lines) and cause the kite to stall and/or land, sliding the bar in will pull on the top lines causing the kite to speed up or launch. It is just a very simple and basic system. Bar out, brakes are on....bar in, kite flies.

The Scout bar and the Ozone bar you have referred to are simple cut down versions of a true Depowerable bar. Take the bar apart, add in a heavier depower line, add in a power adjuster strap and secondary safety system (kite leash), extend the leaders to match the added on components and you have a full depower bar.

Hope that helps clear it up a little for ya.

frefel - 16-6-2009 at 11:23 PM

AWindofChange - thanks for the very complete description of the difference between the foil and LEI. I also learned a lot from the previous thread on this topic which I had not seen (I'm a new member).

I don't mean beat this topic into the ground but I have considered (maybe incorrectly) that ability to "depower" referred mainly to the ability to modify power while hooked-in by pulling or pushing the bar. This ability allows one to attenuate the effects of gusts giving a wider wind range for a kite. If one lets go of the bar of an LEI (bow kite) the angle of attack of the kite becomes minimal and the power close to none; the kite falls from the sky. With this Ozone bar it seems they are attempting to alter the angle of attack by using the brake lines which, as you suggest, the fixed foil was not designed to do. Letting go of the bar would not seem to depower the kite as it would "lengthen" the brake lines. Nope, not the same as an LEI at all.

awindofchange - 17-6-2009 at 12:02 AM

With a fixed bridled kite, the bar actually hooks up backwards from a depowerable kite. The brake lines go to the center of the bar and the leading edge lines go to the outside of the bar....so, letting the bar out actually pulls on the brake lines and stalls or lands the kite. They do this because a fixed bridled kite usually turns best by pulling on the top lines of the kite. Before I get corrected on this, the fixed bridle kite will turn very fast and quick by pulling on the brake lines but doing this usually kills any speed and power out of the kite. For this reason and for the best performance, you turn the kite by the leading edge lines. Most fixed bridled kite bars have a small pulley on the center attachment that will rock back and forth when you turn which also gives input on the brake lines as well.

The crossover bar actually pulls the same brake line when you turn while letting the other brake line out, this is why it performs much better than a standard 4 line bar.

You could hook the fixed line bar up just like the depowerable kites and connect the top leading edge lines to the center but if you let go of the bar the kite goes to full power (all top lines) and it is not safe. The kite also doesn't deliver the best power when hooked up this way.

So your analogy is correct in that regard Frefel.

BeamerBob - 17-6-2009 at 03:08 AM

I was nodding yes to everything explained here so far except the application of brakes in a turn on a fixed bridle kite. It seems to me that in particular on the HQ bar, pulling on the left side of the bar initiates a turn of the kite counter clockwise. At the same time the lines on the right were extended towards the kite BUT the crossover function pulled the line through the pulley at the center and then effectively shortened the brake line on the left thereby enhancing the kites turn. Flying with handles, I wouldn't pull the left handle and apply brakes to the right handle, and that certainly wouldn't enhance any turning if the kite flew and turned at all when doing that. I hope I didn't misread anything in the previous posts. My intent was to clarify something that seemed backwards to my understanding.

awindofchange - 17-6-2009 at 10:07 AM

Bob,

You are very correct. I have edited my post so it is right now. That's what I get for trying to post late at night. :)

Dave62 - 17-6-2009 at 10:44 AM

The bar in question (referenced by the link in the original post) does NOT travel up and down along the main power lines the way a depower bar does. The loop is directly attached to the bar with a FIXED line. I can understand why it would be confusing for Ozone to refer to it as a Depower Loop but that is only because it’s the same loop they use on their depower bars. I’ve also seen the term depower used to describe dumping a kite to its safety. In this context, pulling the release on the loop (and letting go of the bar) would release the kite to its brake lines (attached to the wrist leash) and “depower” the kite, killing it and making it drop out of the sky.

There is no question that this bar is designed for and intended to be used on four line, fixed bridle kites with no depower functionality other than releasing to safety.

~Dave