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Author: Subject: A/R question
Drewculous
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[*] posted on 10-6-2011 at 10:20 AM
A/R question


Every jumping kite out there has a high AR.... Twisters, blades, phantoms, even lei big air kites have a high AR... Unlike beamers and apexs that are designed to keep u on the ground

Im guessing that the high AR means a faster kite, faster at the edge too, which means faster at the zenith (top edge)... Which means up you go!

So lets call the above point 1... First off, let me know if I'm way wrong at point 1....

Point 2
Race kites, vapors, prodigies, etc have a wicked high AR.... So a high AR is needed to race because they are faster by design (not sure why, but I know race kites are fast :lol: someone tell me why a vapor is faster than a viper)

So point 3 (as in the point of the post)
Is a vapor like the absolute best jump kite out there or what? It seems to fit the jump kite bill, but is labeled as a race kite.... Thoughts?

:puzzled:

Summary:
Jumpers have high AR
Race kites have high AR
Are race kites jumpers? (and vice versa)



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[*] posted on 10-6-2011 at 10:35 AM


There is much more that goes into the overall design of a foil other than the aspect ratio.

Race kites do have a tremendous amount of lift in them, but that is mainly because they are designed to produce lots of power at the edge of the window. If you take the kite to the far left or right edge and under speed, it will continue to produce pull. The same is applied to the top edge or apex, if you take the kite overhead with speed, it will continue to pull - creating lift instead of speed.

The problem with a very high aspect ratio kite such as the Vapor is that it has a lower lift/glide ratio, meaning that it will lift you hard but also put you down just as fast. Once the anchor point (you) is loose (leaves the ground) the kite can fold up and will lose power very quickly.

For the absolute jumping kite, your depowerable kites will reign far superior to any fixed bridle kites because they have such an aggressive lift/glide ratio. Meaning that they will lift you huge (partly because of the design of the canopy, partly because of the ability to instantly power the kite up at the exact moment needed) - but they will also float or glide back down slowly (huge hangtime).

A Vapor will rip you off the ground like a catapult, but unless you have tons of skill to constantly redirect the kite and keep it from overshooting or colapsing, it can put you down just as fast and hard.

As always, the larger the canopy the more graceful the decent. This is true with just about any kite regardless of aspect ratio.

Hope that helps.



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ripsessionkites
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[*] posted on 10-6-2011 at 10:35 AM


A/R is only a part of the equation

some brands think that when they say their A/R is X, its going to be race or lifty. you have to ask too, is the AR projected or flat. that makes a huge difference. you'll notice that most designers make their smaller sizes with less AR because its going to be too fast and highly unstable.

A/R + Foil Profile + Bridle makes the kite do as the designer intended.

if you say match a Vapor (flat 5.85) vs Nitro (flat 5.86), the Vapor is faster, because it uses a lighter material, thinner bridle, and it also has less D-Rib material to name a few.

if you match say a Vapor vs Twister II in the same wind same size, the Twister II will lift higher. the vapor was tuned to have min. lift, as with the twister II to have more lift. i know because i buggy jump only with the vapors and i have to size up a lot (guys were riding 4m / 5m / 7m and I had to use a 16m). The Blade was solely designed for lift so they have done lots to make the profile turn fast, hold height, etc etc.

the Charger boosts higher than the Phanny im my books, but thats just me. The Phanny is great for those that like speed on a bar in a bug.

not even close to big air

http://i116.photobucket.com/albums/o7/ripsessionkites/Misc/I...



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[*] posted on 10-6-2011 at 11:44 AM


thanks for the input guys... really nailed my questions...

i figured different animals, but i didnt know if the ends would come out the same! Part of this question came about because i found a review of the Blade 4 as a race kite.... they said they hit good speeds pretty easily (cant remember numbers off the top of my head)

Nice pic Rip!

but i do offer a rebuttal on the charger v phantom big air debate :lol:






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[*] posted on 10-6-2011 at 12:23 PM


Thats one of my favorite jumping videos ever. CTB can chime in on jumping between the 2 kites. I'd vote for the Phantom.



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[*] posted on 10-6-2011 at 05:40 PM


Yup, I would vote Phanny too. That kite rips!



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[*] posted on 10-6-2011 at 09:34 PM


I've never flown a Phantom, but my 16m Scorpion freakin' LAUNCHES me into the air. When tuned properly, it's not a kite to joke around with lol. Not many people fly Scorpions it seems... I think they're quite underrated...



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[*] posted on 10-6-2011 at 10:02 PM


So, if the phanny's have so much lift, why are they considered such great buggy engines....? :wee:



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[*] posted on 11-6-2011 at 01:08 PM


Back to my original statement.... Does a fast kite make a good jumper lol... Phantoms are good buggy engines because they are so stable, and fast (as far as depowers go anyway) but its that same speed that allows for big boost jumps... I dont know... Ill just take peoples word for it :lol:



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[*] posted on 11-6-2011 at 01:24 PM


I think that Kent nailed it: "For the absolute jumping kite, your depowerable kites will reign far superior to any fixed bridle kites because they have such an aggressive lift/glide ratio. Meaning that they will lift you huge (partly because of the design of the canopy, partly because of the ability to instantly power the kite up at the exact moment needed) - but they will also float or glide back down slowly (huge hangtime).A Vapor will rip you off the ground like a catapult, but unless you have tons of skill to constantly redirect the kite and keep it from overshooting or colapsing, it can put you down just as fast and hard."
A while ago I remember somebody doing an assessment of the aerodynamics for a good race wing and stating that you want something that "clears the air" from underneath quickly [the drop line a rock part of Kents comment :o] while my understanding is that a good jumper will "hold that air" which is the float/ glide/ hangtime that you want in a parachute but not in a sailboat.

Thats just my semi educated bystanders take on the situation. BTW a great question that makes this forum so cool.



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[*] posted on 11-6-2011 at 05:36 PM


Drew, Generally, speed is power so the faster the kite flies, the more power it generates. If you fly the Phantom at full speed in a buggy and then rip it up off the deck towards the apex, your gonna go up! Even though the Phantom is designed as a land kite, because of the speed it generates it will rip you off the ground. Problem is that it doesn't really have the hang time (glide ratio) of other kites and you will come down just as fast unless you constantly redirect and keep the speed and power in it. High jumps are awesome on the Phantom, and the glide ratio is actually fairly decent but for ultimate hang time the Chargers (or other PL kites) will reign superior. You may not get as high of jumps on the Charger but you will hang for what seems like forever if you deploy the same technique of redirecting and keeping the speed in it. Also you will feel much more secure and suspended with the Charger over the Phantom.

I would say the Phantom launches like a tightly wound catapult - Rip it hard, boost huge, radical trick while you hit the ozone layer and then back down to earth. The Charger launches like a 747 - massive amounts of lift (without the butt-cheek clenching speed and rip) but while climbing to the apex it is smooth as silk and you can have a mimosa while you wait for the decent.

Now the F-Arc...that is kind of like a Phanny with Red Bull and Steroids.



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[*] posted on 11-6-2011 at 07:52 PM


Quote:
Originally posted by awindofchange

Now the F-Arc...that is kind of like a Phanny with Red Bull and Steroids.


I was wondering why the Farc wasn't thrown in here ?
It was all about high aspect and the trade offs are most obvious.

It isn't exactly a good buggy engine or hang time kite but it's FAST !!!!

When I entered into this sport I thought the Blade was competing on the buggy race circuit? Wasn't it ?



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