Kite Turn Accelerator by Bruno Legaignoux

[tegirinenashi]

I think the turn mechanism is different in the two cases. Bruno's bar twists the kite, so that one side gets more lift than the other. The kite lift gets shifted from the center so that the aggregate force (line tension+kite lift) pulls the kite to one side.

A 2-line kite turns by having dis-balance between left and right line tension. I'd argue that traditional 4-line kites turn by combination of both effects. Certainly, the canopy is twisted, but there is also a disbalance of line tension between left and right (to somewhat lesser effect than 2 line kite).

I finally get the point that Bruno mentioned: pulling back line alone in the traditional 4-line kite design has stalling effect. To compensate, his solution is to add pull in the opposite back line. I suggest that adding tension on the back line at the same side might also work (and even perhaps without auxiliary bar). And here is the implementation of this alternative system:

[FarQueLot]

the fundamental of a tube kite steering system is that they twist the kite by having tension on one front line and the opposite rear line, pulling both same sides has virtually no effect

I think it would have an effect. Two line trainers only pull on one side and they turn super fast

Well it doesn't, this is not a 2 line trainer.

Try the experiment for yourself and try to understand.

Bruno's system is accentuating the twist effect by putting tension on opposite front and rear lines to enable better turning. This is the same as getting a kite off the water by grabbing one front line and the opposite rear line to rotate the kite around and launched.

[Munti]

An interesting feature of this double bar is that one can choose the strength of the turn accelerator.
If you want as much speed as possible and not much lift, place the front lines at the ends of the upper bar.
If you want less speed and more lift, reduce the distance between the front lines.

Very interesting thread!
Can someone explain the relation between speed and lift so even a noob like me is able to understand it?

[AndersP]

Speed is generated by the force that is directed in the kites travelling direction (forward)
Lift is generated by the force that is directed 90 degrees from the kites travelling direction (side/up).

[Munti]

Speed is generated by the force that is directed in the kites travelling direction (forward)
Lift is generated by the force that is directed 90 degrees from the kites travelling direction (side/up).

Thanks. But what I don't understand is how a relatively small variation in the distance between front lines changes this. Does it change center of gravity?

[foilholio]

The principle is that the front and rear lines can steer the kite. Using both steers it even quicker and more effective, less stall etc. Using handles will teach you this.

Quite the opposite of Flysurfers WAC line because it pulls the outside front line rather than inside.

No that is wrong a WAC line pulls the inside front(A) which is similar to the same as this. It however doesn't release the outside as effective as this and is reduced ratio by the mixer.

[BillyGoatGruff]

Was looking good..until...

https://www.ebay.co.uk/itm/Wolkensturme ... 2798515184

[jakemoore]

The principle is that the front and rear lines can steer the kite. Using both steers it even quicker and more effective, less stall etc. Using handles will teach you this.

Quite the opposite of Flysurfers WAC line because it pulls the outside front line rather than inside.

No that is wrong a WAC line pulls the inside front(A) which is similar to the same as this. It however doesn't release the outside as effective as this and is reduced ratio by the mixer.

The WAC system is all on either the left or right side of the kite. This is a crossover bar that pulls for example the left rear line and then at a limit the right front line.

WAC limits oversheeting and increases camber but just on one side of the kite.

The Bruno Bar limits oversheeting on one side of the kite and decreases AOA to a greater extent on the opposite side.

[foilholio]

Sorry I was mistaken. I didn't see the way this works on the opposite front line, obvious now looking at the crossed lines. This is not front line steering, but just exaggerated front to rear line effect. Few problems, line wear and then the bar pressure will be insane. I can safely say no one will use this "idea", outside some curiosity.