Power Kite Forum

So lets chat about speed and upwind performance......again

popeyethewelder - 9-9-2011 at 02:22 AM

Ok...so we know the fastest kite in the world recorded is the Vapor....but that mainly is because there are not many people mad enough to go out there in the extreme winds needed to break records... the data, is really quite limited if we think about.

I have long thought, depowerable kites are the way forward when it comes to speed, I even wrote about it a few years ago on my web site, mainly because you have much more control over the kite, for instance you can start off fully trimmed in, and as the speed builds up let more and more out, as the run comes to an end trim in again if needed...Fixed bridle in these condition in my mind is much more dangerous, you only have to look at some of the footage at NABX 2010 when Arjen broke the record and the year before, to see him getting thrown around like a rag doll, and that before he even gets in the buggy.

I have recently made contact with a guy called Christopher Krug form the US (A PL Sponsored Snow Kiter)...he flys depower kites on snow and ice.....on skis...his top speed so far is 73.5mph, and he is very confident of breaking 80mph..so these great big kites can go quick...this has confirmed it for me, yeah we knew about the 50s and sometimes getting into the 60s...but this guy does it regularly.

The video below was taken a while ago...he is flying a Phantom, the wind I would guess is around late teens....

just look at the upwind performance of this kite about half way through...he is almost going directly upwind, you can see this via the snow skating across the ice.....then after this look at the acceleration when he dials it in....I am amazed at this for such a large kite, just imagine the speeds obtainable on a 20-30mph day....of course space is his problem....its not like Ivanpah where you have mile upon mile to go at....anyway have a look at this

Video 1


Here's what he says about this video


Quote:

I found some footage from a session last season on Lake Chocorua. I had mounted up an old pair of Salomon 1S skis with a new lifter and was testing them out just to see how they felt compared to my regular DH stuff.It turned out to be a damn good day for going fast inspit of the lack of room. I don't know how fast I went that day because I didn't bring my GPS and the goggle battery was dead from the day before. Oh well, it was a good day to be out.The thing I like about this footage is that you kinda get a sense of the speed as I approach the East shore and waive off. I could probably have gone a bit faster but with no snow on shore, glare ice and nothing between me and the trees and rocks you have to keep a margin for error.The kite is a 12m Peter Lynn Phantom 2 prototype. Damn I love that thing.At 1:27 I touched a wingtip, that's why she went down. At 2:15 I hook a good gust and ripped as far as I could. I really like the footage after that of the kite riding the gust out semi at the edge of the window as I work my way back up the lake.Jim Cline was the other kiter on the 5m Frenzy.This was one of the nicest days I've seen on Chocorua. The wind was pretty much straight NW with little variation and pretty consistent gust factor. Usually that lake is a total goat rodeo. =)



and for off board footage at a different location

Video 2



Ok...its not buggying, and I know depower kites have been used for years in a buggy, but now I think if we start using them in vengeance...at the right location, who knows what is possible

greasehopper - 9-9-2011 at 04:42 AM

It's just me, NNNNEEEEEEOOOOOWWWW, chiming in... I got chastised a bit the last time I tried to point a discussion down this road but let's give it a try again.

This was my point in an earlier discussion about achieving greater speeds in higher winds on large wings and the lift to drag ratio "wall". Arcs are typically "fat" thru the section profile and more balance top to bottom along the chord where as LEI's have that nasty turbulence immediately behind the leading edge. Neither of those factors compare the increased drag of multiple bridle lines. Anyway you slice it, less drag equals greater speed and bridle line drag of a FB far outweigh the efficiency of their superior profile shape. De-power is the way forward.

With that said, I still like the violent, sporty acceleration curve of FB over the slow-burn build up of de-power ... Of course, I'm certain much of that is just skill building.
:wee:

snowspider - 9-9-2011 at 08:40 AM

Several questions come to mind. Does varying the AOA on a high end race kite cause inefficientcies or behavior problems? The fixed bridals have line drag , the flying pillows have huge wetted area that provides little or no lift , which one really has less drag. How many pound of pull is each kite producing at any given speed and does this decide which kite goes faster. My guess is kite designers need to chime in without giving away trade secrets.

Fixed bridal guys will say they have more controll. I know at high speeds I'm not feeling the need to be yanking and cranking my kites arround. Depower's turn speed increases as ground speed increases and I have the benefit of not having to change flight path to alter the power or lift. A depower race kite might be more managable during launch and land but that may not be enough of a concern for pro racers to change what they fly.

markite - 9-9-2011 at 09:03 AM

There are a number of other things that also come together for upwind performance. On the dry lake with the right combination of wind and kite power you can get a much higher angle upwind than you can on some other surfaces. In the winter with skis holding a good edge I find I can also get really high angle upwind, especially on ice with a razor sharp edge - but I also tend to use my arcs a lot in the winter and a good chunk of buggy time down on the dry lake.
You really notice it more with kites that sit way out front and develop power at the edge of the window. When over powered get the kite low out front and drive hard upwind and you'll overcome that sideways overpowering drag.

For me it's not only a combination of the versatility to wind conditions (we always have gusty inland winds) but saves switching between several kites during the day as wind is up and down, and also a better choice when the wind isn't quite the right direction on a beach when you need enough power to get upwind one way and then can really let loose with more power to run downwind the other way - just overall more time spent riding than playing with the right kite size for the day.

BeamerBob - 9-9-2011 at 09:41 AM

Being on the cusp of getting lots of riding time at Ivanpah, I too wonder often which type kite is the tool of choice. I hope by getting lots of time to experiment in such conditions where space or direction of wind is hardly ever an issue of attaining top speed for conditions. I have both fb and depower kites for most any condition, so I hope to be a rolling database of what works best in what conditions. I'm going to keep a log of my sessions with estimated wind speeds, max speed attained and kites used. Seeing Krug take that 70+ mph short run on the skis takes a lot of wind out of those that say depower won't go fast.

Drewculous - 9-9-2011 at 11:22 AM

id love to see a new breed of kites...... maybe a throwback.... ridgid frame, razor thin profile, basically a big, high a/r LE(non-inflatable) kite on 4 basic lines.... one simple goal: speed on land

BeamerBob - 9-9-2011 at 11:41 AM

Quote:
Originally posted by Drewculous
id love to see a new breed of kites...... maybe a throwback.... ridgid frame, razor thin profile, basically a big, high a/r LE(non-inflatable) kite on 4 basic lines.... one simple goal: speed on land


Like a 4 line flexi stacker?

Drewculous - 9-9-2011 at 11:43 AM

like an lei, but no edge to create a "dead zone"... the kite would look like this " ) " its profile would be whatever thickness of spar, 1cm? and just a flat sail... no bridals

unstable and crappy to fly... but go fast... lol

i doubt it would work, but if profile thickness, dead zones, and bridals are the issues.... take 'em out

think c-quad-esq... more general arc shape, higher a/r, with phantom bridals (or lack ther of)




of course.... that P2 proto did the job pretty dang well!!!

pokitetrash - 9-9-2011 at 11:54 AM

Quote:
Originally posted by Drewculous
id love to see a new breed of kites...... maybe a throwback.... ridgid frame, razor thin profile, basically a big, high a/r LE(non-inflatable) kite on 4 basic lines.... one simple goal: speed on land


I think the Revolution Blast fills that slot? Seen'em flown, never wanted to try it though. It looked kind of squirley.

awindofchange - 9-9-2011 at 12:05 PM

Yup, for upwind performance the Rev's are hard to beat, and the power per size is incredible. I have buggied many times with my Rev's and once you get the controls down, they are pretty awesome. These kites are so fast that the hardest thing to get use to is working the kite enough to get the buggy up to the speed of the kite. If you don't, the kite just rockets to the edge of the window without you.

popeyethewelder - 9-9-2011 at 01:04 PM

could be the way forward then Kent ....you'll have to get out there and do some comparisons

BeamerBob - 9-9-2011 at 01:12 PM

Quote:
Originally posted by popeyethewelder
could be the way forward then Kent ....you'll have to get out there and do some comparisons


Kent, I'm up for a race any day! I'm SO ready to put some miles in on the lakebed. I don't care a bit about whether I win or not, (though you know I'll be trying) just the knowledge gained from the run is all I want.

Drewculous - 9-9-2011 at 01:49 PM

:crazy:

good god... me talking out of my a$$ is psuedo correct for once?!?!

BeamerBob - 9-9-2011 at 02:21 PM

Somebody has to think of everything. Might as well be you this time Drew! :lol:

awindofchange - 9-9-2011 at 02:24 PM

I know the group was talking about heading out soon. I am looking forward to it myself. Have to get the Rev's out and give them a good run.

Feyd - 9-9-2011 at 07:16 PM

I just wanted to chime in quickly.

I've never ridden a buggy so I'm not able to speak to how well a depow works in that application. However Popeye's description is pretty much exactly how we do it on skis and I (obviously) agree with his theory.

I look at it like this...

First, you never know unless you try. I know the designers can crunch the numbers and say a wing will or won't do something but you never know for sure until you try it in a real world situation. Aviation history has shown us this time and again.

Some theories on the sound barrier before Yeager broke it are a good example.

Second, I don't know what a wing "can't" do. I'm blissfully unaware and as a result I'm not hindered by "the facts". I get on a wing and I do what I want with it and if it doesn't do what I want I MAKE IT DO IT. Or try as hard as I can. I've flown a fairly broad variety of depows and sometimes I find "limitations" only to have different conditons enable me to prove myself wrong. And sometimes someone else proves me wrong. Just because I can't do it doesn't mean someone else can't.

Third, the "pillows" are fast. Even the lower AR one's can haul the mail in the right conditions and I find that most depow kites can. I bagged 67mph on an HQ Apex once on Chocorua. I never would have guessed! Too bad I ran out of space. That's the problem here is lack of space and having to back off just when it starts to get good. We have some new riding areas now with room to run. I can't wait.

Anyway Arcs are fast. Yeah they lack bridal drag and they're thick. I think the lack of bridal offsets the drag from the wing thinkness but I don't know. Again, I don't need to know to fly it.

Fourth, I use what works for ME. I've never ridden a Vapor and I doubt I will here because FBs really just suck to fly here most of the time. Bridled in general are pretty unfriendly here ,that's why we got into Arcs. But I think that a lot of people gravitate towards a given model because the accepted thinking is that it's the kite for the job w/o actually testing it againt others and really figuring out what works for them.

The Vapor is obviously fast. It's designed specifically for it and I'd LOVE to try one. But my Chargers and Phanny 2 can give it a run for it's money but you wouldn't know it by looking at 'em. :wee:

Falling asleep.G'Nite.

DAKITEZ - 10-9-2011 at 12:17 AM

popper I think what you are really getting at here is maybe depowers are possibly as fast as a fixed bridle but safer and you do not have to be a nut to pull off high speeds? I do not think the current line up of depowers can keep up with the fixed bridle race kites IF you were to compare them straight up.
It is no secret that I prefer depower (but I am not a speed demon either) My theory was always for most riders (excluding pros) that you would be faster with a depower. And the reason is the wind range a pilot gets out of that kite. To have a super solid run on a fixed bridle you need super stead winds and the exact perfect wind speed for the kite you are flying. Most people do not have this luxury. People will have gusts. So do you play it safe and size your kite for the gust? then you will be underpowered the rest of the time. Or do you get a kite for the steady wind speed and hope you dont have an obe when a gust hits? Most people pick to the side of caution and end up flying underpowered. Where with a de-power you can be well powered in the steady wind as well as the gust all with one kite.
The time this does not work is when you have people like Ozzy and Arie that will fly a 7m vapor in 30mph winds ... they are the exception :) But for many of the folks here in the usa a 3m fixed bridle is their happy kite in say 15-20mph (Before I get slammed I am not talking about everyone ... but I know many people this is true) Where you could easily be on a 7-9m de-power in these winds. In this case there is just no way a 3m is going to hang with a 7-9m bridled depower.
I see depower as the way of the future. I know alot of people dis agree and that is whats cool about this sport. we can all fly something different but at the end of the day we are all just a bunch of wind junkies :)

nocando - 10-9-2011 at 02:10 AM

My two bobs worth,

Had a fly this afternoon nice mental westerly 15/30+ Ks
I first rigged up 5m Apex but was overpowered couldnt get into the bug trmmed to max
Rigged up 3m Apex what a hoot half trimmed and having a great time, my mate turns up and flew his 3m Fb then changed to a 2.5
was keeping an eye on him as wind was not favouring FBs bow ties mental shifts etc, while he was battling I was haviing a ball
the potential for speed with these kites is unknown as I run out of room too quickly, love the punch they have coming out of a turn.
Am hoping tomorrows blow equals todays :wee:

popeyethewelder - 10-9-2011 at 11:47 AM

C quads.....old school....???

there are some guys around Lincoln Uk going by the name on youtube as Knobs on Strings....these guys are totally mad and fly nothing apart from C quads....and they certainly know how to use them and pick them up for next to nothing these days....and my god, they pack some grunt....could these be the answer

BeamerBob - 10-9-2011 at 01:58 PM

There was supposed to be a batch coming over from the back corner of some PL storage. Don't remember the outcome.

Feyd - 10-9-2011 at 02:08 PM

I have a friend that has a whole quiver of C-Quads. Never flies them anymore because he's on V2's or some flavor of Flysurfer Speed. He says pound for pound they're hard to beat.

I've never flown one, maybe I'll get him to bust them out this winter. I'd love to try them.

Don't know about the stuff from the PL warehouse. A lot of that stuff was promised for the SLArc project and Rudeboy just got a shipment a month back. RIcardo has some kind of deal lined up to get a bunch of the surplus kites shipped over ( mostly F-Arcs?) but I haven't heard hide nor hair of it since he posted that he was gonna be dumping the kites. I don't know if there were C-Quads in the mix or not.

Sorry Popeye, I feel like we sorta hijacked the thread. Back on track.

I'm not sure I can agree with Dakite's statement that a 3m (asumming FB) can't hang with a 7-9m sheetable. I've ridden with a guy while I've been in exactly that situation and he was not far off my speeds. That in part is perhaps I was tipping the balance point of power/edge hold and drifting a little.

I rarely get pulled off my edge but it is possible. I know I see a lot of people who tend to think they need a lot of power to go fast. They rig a bigger kite than is appropriate for speed in a given wind condition and tend to loose edge bite as a result.

Sure you feel like you're hauling the mail and you are to a point but it's woefully inefficient and a lot of work.