Crossbow Warning?

[Blackbird]

yeah, a warning about your Crossbows. Following is the email I sent Cabrinha after an episode at Crissy. Read the whole post and you'll get the full story. Email and response from Cabrinha. It's good, and you should know about it.

Original email:
Umm, yeah, where to start. Problem with the Crossbow 12m? Today was the thrid day flying my Crossbow 12m. I was in the bay, San Francisco, in the middle of everything. Literally a mile from anything. Just spent two hours flying the kite. In fact, I sent you an email yesterday raving about my first two days on the kite. Well, today, issue number one popped up, and vanished at the same time.

Issue: Flying the 12m in 20 mph winds, having a blast. Time to head in. Pulled a fast up turn, back through the power window. Right as the kite was passing the power zone, POW. POW as in the kite seemed to fold in half from the back forward, and turn inside out. Shit. I figured something broke. Ok, wrap up the lines, start the self rescue, managed to flag a boat, got to shore. Layed the kite out, and couldn't find anything wrong. Ok, will have to look into this tonight. Well, here it is, tonight, and I've run the lines/bar out, no problems. No breaks, no tears, no kinks, nothing. The bar and lines look perfect. Ok, I must have missed something on the kite. So, I pump the kite up and check all the bridle lines. Nothing broken, nothing out of place, no tears, nothing. NOTHING! Did I hallucinate?

Question: Is there some sort of flight maneuver I inadvertantly did to cause the kite to suddenly invert from the center strut, fold in half, and fall out o f the sky? This is exactly what happened. When I swam up to the kite, the center strut was pulled 180 degrees backwards, wrapping the kite in itself as it was folded in half. This was a pretty good indication to me that something broke. I found NOTHING! I'll be taking it out tomorrow to see if I can't find something when I fly it. I am baffled. I sure would appreciate some possible insight. The idea of using this kite just became a little sketchy if I can't find anything wrong with it and this happened. I mean NOTHING wrong that I can find. Believe me, I have scoured it. Anyway, I'll know more tomorrow, but am looking for any bit of info you may have.

Response from Cabrinha:
Thanks for contacting Cabrinha Support

The inversion that you experienced usually occurs from insufficient strut and/or LE pressure.

There is a reason why these kites do not have one pump and thatís because the struts need to be a higher pressure than the LE. If you have a strut that is not at pressure the LE can fold on that mark. If the LE is not a sufficient pressure it can roll and also fold in and invert. This usually occurs when the kite is put through the power zone but sheeted out. The low attack angle gets so negative that the canopy starts to blow down from the top side. When you have insufficient bladder pressures the kite simply has no support. BOOM, sheís inside out and in a knot.

Now there is a way to re-launch and get back to the beach if this occurs again.

You have to just play with the rear leaders and try to get the kite to lay out flat again.

Most people in this situation just start pulling on lines and this simply makes the kite knot up even more.

Swimming at it and trying to get it to spin around will get the kite back in the sky.

We have been testing the kite in these situations and it still stands as a 100% re-launch success in even the worst knots.

Result:
As you can see, basically end user error or a leak. I'm paying extra attention to the pressures. Cabrinha has been extremely responsive. This kite has been flying great ever since. Still highly recommended.

[kitekarl]

My friend had this happen at rooster rock in 35 knot winds on the cb 9M. He had it bowtie and said that it was way sheeted out at the time so it sounds like you had a similar experience. Seems like there's a spot when you've got the kite directly downwind where you don't want to sheet out too far. I'll post this on the nwkite forum and see his response.

[Guest]

Sounds like the bladders need to be properly inflated.
If the problem continues a span line (like the rrd 5th line setup) should prevent the kite from flipping inside out. I've heard the guys with the early xbows say that they've actually flown the kite inside out, and the kite flew, and did not damage the kite.
-bric

[Dano]

I experienced this exact phenomenon 3-4 times on a 9m X-Bow and perhaps once a 12m (while demoíing at the sandbar). The worst of the events took place during a down-winder to Rooster Rock on Saturday morning (~11:30AM). The wind was in the 35mph range with higher gusts. I was steering the kite down through the power zone as I was descending from a big jump. Just as I landed, the kite did the POW, POW, POW thing. As the kite tried to right itself (I think I was trying to steer it up) the leading edge wrapped around itself on one side of the kite. The bridle lines also wrapped around the leading edge. The kite dropped to the water and I activated the frontline safety release to prevent damage to the kite. Fortunately, I was close to shore so I swam in and Tonya grabbed the kite. Once we unrolled the leading edge the kite was fine & ready to fly. Not sure that I would have been able to fix the problem in the water by pulling on the lines or swimming toward the kite, as Cabrinha stated in the previous post, as half of the bridle lines were wrapped around the kite.

The leading edge was fully pressurized while the struts were probably at a lower pressure as we had left the struts inflated over night and did not re-pressurize when the kite was re-inflated.

The other times this happened, the kite popped in & out 2-3 times and then righted itself as it shot strait up through the power zone. Fortunately, the kite de-powers instantly so I wasnít even pulled out of the water.

Tonya has ridden the kite in high & low winds and has not experienced this effect.

Phenomenon seems to happen in higher winds when the kite doesnít have much rear line tension (supports info Bay area rider received from Cabrinha).

Weíll be sure to watch our LE/strut pressure and report back on this issue. Thanks for the info from Cabrinha. ~Dan & Tonya

:arrow: http://www.nwkite.com/forums/viewtopic.php?t=544

[windhorny]

I wonder if you relocated the position of the reride ball a little lower if that would prevent the kite from being able to fly forward so much. Of course this would slightly reduce the amount of depower. But the kite depowers so damn much as it is it seems if you needed more you would just use the depower strap.

[reality check]

OK, so the xbow has a lot of buzz going for it - it's great for the sport. I want to sprinkle some reality into all the glowing wine induced reviews ;-)

In the delta a few folks have been flying the xbow in a range of conditions. My best attempt to match performance is to compare the xbow ridden by an advanced rider of similar weight and board.

Him: 175lbs, riding slingshot sx board.
Me: 225lbs, riding custom amundson board, same width as SX.

Top end: Big wind day of high 20's, most people on 10's and 8's. Xbow rider on 12, me on 12 vegas. Both of us were jumping pretty high - I almost landed on top of a friend - big lofty jumps on both kites. Kite turning seemed the same to me: I was able to follow him turn for turn. Upwind seemed same to me: we both smoked up wind. Coming into beach, I was able to walk not assisted just as the xbow rider. In reality, I would have been having much more fun riding on my 10m kite, but did not have time to switch and just made what I had up in the air work.

Low end: Light wind day, where most guys were on big kites. Both of us went out on 12'. We were able to stay to weather the same, and same jumps/tricks possible.

The kite looks cool and is pushing the design envelope - which is great for the sport. From a performance pt of view, I don't see a big difference from my vegas 5th line kite.

The purpose of this post is not to kill anyone's buzz about the new kites - as a matter of fact, I want as many people stoked about the sport as possible.

As they say in car commercials, your milage may vary.....

Good winds + waves, Zeev.

[knyfe]

Zeev, 50 lbs weight difference is really a lot. This makes it hard to compare directly. On a windy day I would like to have 50 lbs more until I am in the water.

Use the Xbow by yourself the next time and switch back and forth. That helps to understand way more. Thats what I did with the smellfish in light winds. My Yarga was way better.

Still very "interesting" to hear from the pop pop effect ... This reminds me to the kite with the battens instead of the struts (forgot the mane ... , or wasnt it the first and also the last Windtools tube). One fo my friends pumped the kite up vise versa and was surprised why it is looking so different ...

K

BTW. I just realized that I never saw a Smellfish here in the Bay beside the test version ones?!!? How has ever seen one?

[andyandmarlys]

I have had 2 of my '04 slingshots invert themselves in the air in high winds. (both a 13m and 9m) In one case, the kite folded in, fell in the powerzone, and then unfolded in the heart of the powerzone... It was such a surge of power that I broke my carbon bar in 2 places, and broke a line as well... After this, I made sure to keep my kite pressure on the high side...

[HAWAYA]

JUST WONDERING IF ANYONE KNEW IF THE FLATTER FLYING PROFILE MAKES THE NEWER CROSSBOW TYPE KITES MORE PRONE TO INVERSION THAN TRADITIONAL C KITES. COULD THIS BE FROM LINES GOING A LITTLE SLACK AFTER A GUST OR OVERJUMPING THE KITES?

[plabrevo]

fwiw: http://www.ikiteboarding.com/article_detail.aspx?id=175