C-kites and slack time

[sloughslut]

I just bought some sle kites having only rode c kites. the SLEs are nice for alot of things but i will always keep my 10m C, in steady wind it is the best feeling of power, for me. Plus they look cooler and there are no bridels or pullies to get all tangeled up. and i think the 5th line kites relaunch quicker. :)

[adamrod]

Ok. I posed the question to resident bay area kite designer Bill Hansen:

Adam:
That is an interesting question.

When I designed custom kites for Flash Austin and Lou Wainman, they liked 'C' Kites because they had lots of 'pop,' turned quickly, were predicable and stayed 'powered up' most of the time.

My thought, based on your question, is twofold:
First, a kite with more 'pop' means the rider will spend more time at the apex of the jump which is a sort of weight-less zone where the kite and rider are neither rapidly rising or falling and the lines are more or less slack.

Second, a 'C' kite stalls in a more complete and direct way while maintaining a sort of 'parachute' quality in the process where a higher PA SLE is less likely to catastrophically stall and will therefor recover more quickly. Part of this behavior is related to the SLE bridle attachments which tend to pull on the leading edge where the 'C' the attachments are on the wing tips with less variability of AOA and less proclivity to 're-attach' until forward motion is re-established.

That is my take on it...
Best regards,
- Bill Hansen

[adamrod]

So, my understanding is that since a SLE/Hybrid is attached by the leading edge (via a bridle), it can adjust angle of attack (even when unhooked) in order to re-attach to the laminar flow, powering up the kite.

Since the middle lines of a C-kite are attached at the wingtips, it can't adjust as much after stall, so it takes longer to regain laminar flow, thus not powering up as quickly and leaving the lines slack?

well, that gives a possible explanation for the hype...

[KillaHz]

Yeah, it's all about the load to get the pop and if when you load, your kite shoots forward you're not going to get the pop... C kites load better for the most part, they sit further back and tend to stay there. The key is the part Bill mentions about better pop leading to the weightlessness feeling at the top of the jump.

...and Carl, you ain't riding C kites any more you old fool. You're riding buckety, delta type SLE's. Sorry to break it to ya...

[S I LOCAL]

DAMIT! ](*,)

[ramsey]

how does AoA change with no sheeting? You can tune your kite to make stall unhooked no matter what kind of kite.

BTW, I love sandwiches. Especially turkey.

[adamrod]

since a bow/sle is supported more on the leading edge, the AoA can change more when unhooked due to stretch and tension in the back lines and canopy. (i think)

(this is just my guess)
stall is when airflow no longer flows in the direction of leading edge to trailing edge. Now, if the front lines are attached directly to the leading edge (via a bridle), it's easier for the kite to recover from a stall because the pivot point is at the leading edge. this leaves the rest of the kite available as a moment arm to tension the back lines and flex in order to resume laminar flow over the airfoil.

on a c-kite, the front lines are attached at the wingtips so the leading edge is protruding forward past this pivot point. so there is less torque available to stretch the lines while unhooked, meaning the kite stays stalled longer?


in the extreme case, look at a bow kite when completely depowered. back lines slack. if you were to unhook, you wouldn't get any pop because the kite will never stall. the kite will just tension the back lines to the point where it maintains the AoA necessary to maintain laminar flow.

the extreme example of a C kite would be a 2-line C. Lines attaching at the center of the wingtips. since half the kite is in front of the pivot point and half the kite is behind the pivot, it's more willing to stall. the front half of the kite is trying to exacerbate the stall and the back half of the kite is trying to recover it. the completely depowered bow doesn't have "the front half of the kite" because the tow-point is at the leading edge.


in the end, a better rider will always outperform a better kite, but i'm starting to understand why C-kites might generate more slack time than bow/sle kites. In essence, it's a less ideal airfoil, which explains why bow/sle kites outperform Cs in aspects like power/sqm, upwind performance and most other things.

finally, i prefer sandwiches with bacon and avocado, but turkey is nice too.

[Hansen Aerosports]

Ramsey:
Most SLE's have higher projected area and if they are 4-liners, they distort somewhat under high loads (near stall) and the effective AOA in the center is reduced causing them to shoot forward. If you tune it to a full stall unhooked, you won't get much unhooked 'pop' or hangtime. 'C' kiters usually tune their bars unhooked so the kite is at full power. The kite only stalls out when it looses forward speed and the kiter begins to descend which increases the AOA. 'C' kites also do not distort as much under load, at least such that the AOA changes in the center so they stay put rather than shooting forward...

how does AoA change with no sheeting? You can tune your kite to make stall unhooked no matter what kind of kite.

[EvanOR]

C kites have their place (the reason we continue to make the Diablo), but like Ramsey said, it's the rider......and a good SLE/Hybrid offers more performance than 99% of the the riders out there will ever be ever to take advantage of (myself included). :)

The proof is in the pudding - http://www.vimeo.com/2364251

Happy Holidays to all!

[vdeub]

The proof is in the pudding - http://www.vimeo.com/2364251

now that i ve got a OR , do you think i will be able to walk on the water like him ?
does this trick have a name ? looks so cool ...