Kite Size for High Altitude Kiting


I am planning a trip to Mustagh Ata (7600 meters) in July. My plan is to ride a kite to the summit. At first, it all appeared pretty straight forward, but I have been getting MANY opinions about the kite(s) I should be using.

The wind on the lower mountain should suit my 10 m Bandit, but higher on the hill, it can get pretty windy. Nonetheless, the air pressure at that altitude is less than half of what you would encounter at sea level.

It appears that if I have time to wait for good conditions (I do), I should be able to make a run for the summit under 50-60 Km/hr wind (perhaps 30-35 knots).

So the question is, what size kite should I bring to go uphill through heavy snow at 25000 feet above sea level.

Any help would be appreciated.

M

I think you still need to size for the wind primarily. I would think the lower air pressure might actually speed the kite up as it is meeting with less resistance as it cuts through the air but regardless, if its blowing 30 or 60 kmh/hr that's what its blowing and if an anemometer feels that so will a kite.

VERY interesting question.

As a scuba dive instructor, I'm fairly proficient at Atmospheres and Pressure, but I think what your real question is is Air Density. As Air Pressure, is simply the weight of the air above you, at sea level which is 14.7 PSI. Humid moist Air, is heavier than dry desert air.

this air pressure vs density charts and links may help you calculate, that a 3 meter kite at sea level, might power engine to be equivalent to a 5 or 6 or 8 meter kite at altitude.


http://www.engineeringtoolbox.com/air-altitude-density-volum...

Thank you for your replies.

You guys appear to have come to contradictory conclusions. I would tend to side with Windy Heap in this argument because it appears to me that air density (as a function of air pressure) would be the underlying mechanism involved both in powering the kite as well as providing resistance.

Whenever I descend from altitude, the air feels thick in my lungs and helicopters cannot fly very high due to low air density. Although the anemometer is spinning fast, that is just an indication of the speed with which the air molecules are passing it, rather than an indication of the overall torque provided by the wind.

That Engineering toolbox link is GREAT. Thank you so much.

I have decided to bring my 10 m kite to the top, under the assumption that its power will diminish with elevation. When I get back, I will let you know if this is correct. If it isn't correct, this thread may end with my obituary. Hahaha.

And YOU'LL be on 100% full o2 also, or just a nitrox enriched air from normal 28% o2 at sea level, up to 34-36 or 40% more o2 like Nitrox ? or higher %?

I assume o2 toxicity is a concern for climbers? I don't know.

I rappel and gravity is my friend. Heck if I want to hike, my Llamas pack my gear in (we have 4 of them)


You've got man-clankers, series man clankers.


GoPro footage, or it didn't happen.


you rock.

Generally, no climbers use supplemental oxygen below 8000 meters.

Furthermore, I am of the opinion that if you cannot make it to the top without supplemental oxygen, you have no business being there.
I would far prefer to live in a world where only 20 elite climbers have summited Everest at the end of a 20 year apprenticeship in climbing, rather than in a world in which that sacred place can be visited by any joker with a visa card.

Llamas? Seriously?

Lift and drag are both dependent linearly on air density and to the square of wind velocity. You will not develop the same amount of power at altitude as at sea level, assuming identical windspeeds.


Humid air is not denser than dry air at the same temperature. Water vapor is actually less dense than the mix of gases in air. Humid air is less dense than dry air of the same temperature.

Warm air is less dense than cold air. Don't confuse temperature with humidity.


Best of luck on the expedition.

krumly

Quote: Originally posted by mashimisha

Furthermore, I am of the opinion that if you cannot make it to the top without supplemental oxygen, you have no business being there. I would far prefer to live in a world where only 20 elite climbers have summited Everest at the end of a 20 year apprenticeship in climbing, rather than in a world in which that sacred place can be visited by any joker with a visa card.

Well said, I couldn't agree with you more!!

I know Mustagh Ata or Pik Lenin are probably about the easiest 7000+m peaks you can do but I assume you are doing some acclimatisation climbs in the run up to this? well technically easy. a lot of expeditions still fail. its got a really low success rate I think.

Why not pack a 4,6,8,10, and experiment? I have never been that high but even at 6000m every little bit of weight is a pain in the ass. Its like hiking up hill with a hangover. You will have no hassle getting sponsored for this - red bull would jump at it, ozone would give you kites

Its actually pretty worrying to me that you are on an internet forum asking what kite to use because 7000m is a serious altitude and you should be absolutely 100% sure of every piece of gear you have.

And what you are planing is to basically beat the snow-kite altitude record by 1900m! Nobody knows if its even possible to kite at that altitude. Johan Civel who is a pretty amazing mountain snow-kiter tried a 5,200m summit in Patagonia and failed. As far as I know nobody has beaten that Russian guy who did 4700m on elbrus a few years ago.

Its a great objective and I will be happy for you if you prove me wrong but if you are a good enough altitude mountaineer and mountain snow kiter to even try this then you should be giving advice not asking for it.

Being able to climb 8000m peaks without oxygen is very dependant on physiology so to some extent its as much of an accident of fate as being able to afford a supported expedition. People use bottled o2 to make up for the lack of natural o2. they also use clothes to make up for the lack of natural heat! I don't understand why so many people outside of altitude mountaineering get so worked up about it.

even so, hat off to you if you have topped everest without O's, I couldn't do it. it takes me a few days to even be at 3-4000m without struggling.

We hike locally to 10000 feet + and I can't say I notice the difference in air density. I don't seem to be breathing harder than the activity would warrant. I live at 2000 feet so it is a significant elevation. I'm not sure if we aren't up there long enough to have side effects, but we haven't noticed any.

You are absolutely right about everything you have said.
I have been over 7000 meters several times, including 2 weeks ago, but every trip up is a new experience.
I am planning to bring a ten and a six with me and, as you say, experiment. I have no idea whether this is even possible, but I DO believe it is worth trying.
As for trolling on forums for advice, I think that this has been a very good idea. As you pointed out, nobody else has done anything like this before.

After 3 weeks of acclimatization in Yunnan and then Xinjiang, I will be skinning up on telemark skis with my gear on a sled. I have enough time not to have to push through either before I have acclimatized or while the weather is dodgey. Many attempts end in failure because the participants either cannot or refuse to wait for a suitable window.

I appreciate your advice and assure you that I am not liable to do anything stupid. I missed summiting McKinley by 50 meters because to continue on in that weather would have been too dangerous.

Thanks everybody for your advice. I will keep you informed of my progress. My partner has a video camera and I have a GoPro.

From my recollection it appears to me that the major problem in the
area can be wind direction. It is very difficult on other than cramponable
surface to make it uphill with a load on beam reach – even a broad reach can
be questionable. But I like the idea – more than a few years back I would
gladly join you. In that case I would probably pack a half a dozen Nasa
Wings (1.5 –8) flown on 5 lines, no more than about 4m long.

Quote: Originally posted by Prussik

But I like the idea – more than a few years back I would gladly join you.

After 45 years of skiing (30 on tele gear), I have to try now, before I stiffen up like a frozen fish.

Quote: Originally posted by Prussik

In that case I would probably pack a half a dozen Nasa Wings (1.5 –8) flown on 5 lines, no more than about 4m long.

Please send a link about this. I looked it up but couldn't find any mention of this kiting solution.

After moving from dreaming to visualization of reality it didn’t take long for me to conclude that the chances of using a kite there for more than 50% of the distance above the base (which would be my arbitrary viability criteria) are slim to none. This is based on my assessment (right or wrong) of the combination of topography, surface and wind plus all the intangibles of high altitude and disregarding the possibility of an extraordinary luck. Therefore instead of the (theoretical) option of joining you I would rather opt for something less original but milder and doable like...may be a Greenland traverse. Unsupported solo ?. Has that been done ?.

For a choice of the expedition equipment – inflatables would be the worst choice I can think of. I would seriously consider Nasa’s – may be not in the “standard” set up configuration but after some adjustments which take care of most of deficiencies well documented and often cited as their shortcomings. For power/weight ratio nothing comes close. They also fly well on very short lines which I consider an advantage for extreme environment even if it means sacrificing some power. Since I started experimenting with them out of curiosity I am impressed how well they perform. And my strong preference is for a 5 line set up especially for challenging conditions. Needless to say one has to be a competent FB kiter to benefit from this solution. I am not aware of anybody else using them this way. As for the changes I’ve made which revised my opinion about these kites – I will elaborate on them later if someone is interested.

Quote: Originally posted by Prussik

F I would seriously consider Nasa’s – may be not in the “standard” set up configuration but after some adjustments which take care of most of deficiencies well documented and often cited as their shortcomings. For power/weight ratio nothing comes close. They also fly well on very short lines which I consider an advantage for extreme environment even if it means sacrificing some power. Since I started experimenting with them out of curiosity I am impressed how well they perform. And my strong preference is for a 5 line set up especially for challenging conditions. Needless to say one has to be a competent FB kiter to benefit from this solution. I am not aware of anybody else using them this way. As for the changes I’ve made which revised my opinion about these kites – I will elaborate on them later if someone is interested.

I cannot imagine why anyone would want such short kite lines. Please explain this kiting system you have developed. I am very curious.

Nobody said you have to use air to inflate an LEI if you are using it at altitude. I'm sure there must be a chemist out there who could recommend a more stable gas mixture that would not expand as dramatically. Maybe... Pure speculation on my part. What Height is BC? there are only 2 climbing camps aswell right? so there might not actually be a dramatic increase in pressure inside the kite as the pressure outside changes. Its not like you will be infalting them at sea level.

I started using inflatables for snowkiting almost immediately for a fairly simple reason. Thick kitesurf lines and simple bridles are way easier to sort out when you have a pair of gloves on than more complex foil bridles.

They are also more stable in gusty mountain winds (only Arcs are as good) and they are the only type of kite I have tried that will drift along with you if you board or ski towards them. Foils fall out of the sky almost immediately if you give them too much slack in the lines. This might not be an issue climbing but it is for short downhills or descending traverses. An LEI is never going to backstall and bow-tie itself through its bridles in turbulent mountain winds the way a foil can. try sorting that out at 7000m!

They are a lot more bulky to carry around obviously but I would not discount them completely.

Take a look at the Nasa's too. I wouldn't discount anything you havn't tried yourself.

Quote: Originally posted by lives2fly

Nobody said you have to use air to inflate an LEI if you are using it at altitude. I'm sure there must be a chemist out there who could recommend a more stable gas mixture that would not expand as dramatically. Maybe... Pure speculation on my part. What Height is BC? there are only 2 climbing camps aswell right? so there might not actually be a dramatic increase in pressure inside the kite as the pressure outside changes. Its not like you will be infalting them at sea level. Take a look at the Nasa's too. I wouldn't discount anything you havn't tried yourself.

You have echoed my thoughts exactly. The drop in air pressure is incremental and I will be releasing air from the kite every night to get it into the tent. Stability is my main concern. There are 3 camps between BC and the summit.

The Nasa's look like a wonderful idea. What a project. Does anyone have links for sourcing materials?

Pressure adjustments would be the last of my concerns – having any would be. I wouldn’t like to test the low temperature durability of an inflatable in these circumstances. We don’t crash our kites ?. Well – I would not bet on that in turbulent mountain air. One can also crash a foil and blow out a cell but steps are taken to minimize that possibility.

How about the wind increasing 3 – fold or more ?. Having been in these situations a number of times all I can say is that the easiest kite to handle in this kind of emergency is a flagged out FB. Much more difficult is to hold on to a depowerable foil (naturally about 2.5 times larger) especially closed cell foil. And even though I have never had the pleasure of doing this with a depowerable I would say it will be impossible to hold on to it in conditions radical enough and hook it in to a screw or a deadman. But assuming you managed to hook it in to your deadman – then what ?. You can walk up to a foil, squash it into a relatively small package, put a strap around it, walk back and wind in your lines. Try this with an inflatable.

One can be lucky and cover the distance with one kite. I wouldn’t count on that. Then weight and bulk issues, bad enough for one, are quickly becoming unmanageable. There is no perfect solution – some choices can be just worse then other.

Quote:

I cannot imagine why anyone would want such short kite lines. Please explain this kiting system you have developed.

I fly all FB’s on 40 –50 m lines so I would be the last person to advocate short lines. However, in extreme conditions I certainly prefer very short lines, if the kite can handle them, for the ease of launching and packing and handling the whole mess in extreme circumstances. I can drop Nasa at my feet out of the bag, unwind a few coils off the handles and go. Same in reverse.

I haven’t developed a “system”. I simply adjust Nasa’s bridles to make it behave closer to a good FB and fly them on 5 lines to retain the benefits of brakes as well as depower.

Prussik - have you flown an inflatable kite in the last few years? because the deficiencies you are describing may have been credible in 2004 but not now.

The effect of very low temps on Bladder materials is certianly worth investigating if very low temps are expected but I have experienced no problems in 0 to -10 degrees Celcius.

As for ease of handling there is no competition! if you get a design that depowers by flying to the edge of the window then all you need to do is let go of the bar! My cults or bolt will just scoot off to the edge of the window and sit there on a wing-tip waiting for me to tell them to do something. With a bar on a long strop like the Naish Uni Con they are almost totally depowered at this point. Cabrinha is good too with the addition that if you pull the IDS the kite falls canopy up into wind where the airflow tends to hold it down.

This makes self landing easy even in atrocious conditions. I tend to use pickets (snow stakes) in the mountains as they are quick and easy to place. just fly the kite to the bottom edge of the window and clip in first the leash and then the chicken loop. Then just walk over to your kite and get it.

As for pack up you pull the deflate stopper and roll it up! its not difficult.

Obviously we are talking about different kind of conditions.

mashimisha , people have been debating inflato, fb, depower foil for long range or high technical situations but here are my thoughts....

IMO inflato is out. In harsh alpine conditions the last thing I want to deal with is hauling a pump, inflating tubes and dealing with both the bulk and the weight. And if you get a leak, what the heck are you going to do up there? Inflatos have come a long way and the safety systems and depow is top rate. But I wouldn't trust my well being to one in the wilderness. Using the damn pump in the cold is enough to put me off. The thing feels likes it's going to shatter. And there is no way that an inflato is easier in overall handling than a foil. I can have an Apex 4 out of the bag and in the air in less than a minute if packed correctly and repacked in about 10minutes if done right, 3 if done ugly. (believe as Prussik described some days ugly happens.)

FB, are out. Without depow you are boned. You can have enough power, say below a ridgeline, but after some elevation gain or where the wind is compressing on the ridge you can be completely over powered. You'll have to haul either multiple kites or lines or both. FB are awesome for raw power but you need more than simple raw power for something like this.We regularly get winds that will not allow you to stake out a kite here.

Open cell depow are the best option IMO. But even open cell depows have their issues. Anything that uses backlines as the safety is only effective within a certain wind range. A kite solely on it brake lines, like early Frenzies, Montana, Apex Access etc.... will still generate a hell of a lot of pull in some conditions. 5th line works a bit better but can be a hassle or messy. Flag out systems are safer IMO. But at least you can vary the power on the fly, stay with one size wing and with extra line sets double or triple the already broad wind range of a given size. They're light, manageable and proven in many alpine high altitude/ remote environments.

Mountains have so many variables it's ridiculous. Small variations in terrain can cause substantial rotors that can at best have huge wind speed variation and at worst either loft you or knock your wing to the ground while you're fully loaded on a heavy incline.

I ride Peter Lynn Arcs 90% of the time. For variable conditions and massive wind ranges I have found them to be the best kite out there. I fly them 1000's of miles a year and usually in remote areas completely unsupported. They're tough, efficient, huge depow range and un matched gust handling. I'll fly them rarely in alpine situations but lakes are my primary riding enviro.

That said, they are closed cells which helps a lot with luffing and other things but if you blow a cell out you're pretty much in the same boat as an inflato. SO for your application I probably wouldn't go with an Arc. Nobody I know here is flying anything but open cells up high. Out west a lot of people are riding inflatos but my guess is they aren't venturing too far from support.

Your kite equipment shouldn't be different than any other mountaineering gear. You need light weight, reliable, easy to repair, versatile. Open cell depows meet all that criteria.

Hey Feyd:

I agree with everything you have said. Thank you for taking the time to outline all of this.
One last thing, WHICH open cell depows do you like?
Any in particular?

M

Too bad you can't get a hold of Chasta Guillaume on this subject. He probably isn't the best in the world, but he seems to have a lot of experience with this subject.

Really, not too complicated.
Air up high is cold, more lift.
Air that is warm is often down low, less lift.

Cold air is more dense therefore has more lift and you can down size the kite size.

From many moons of experience flying here in mountains of NH as well as mountains in Colorado, Utah, Canada etc.

It is ease of use and quick set up that is best. Light kites are great too BUT not the priority.

Bringing extra line sets of different lengths may be the ticket. As well as a repair kit.

6-8 m kites are usually good for strong winds,

12-15 m kites for light winds

open cell foils


http://www.ikon-kiteboarding.com/en/product/snowkite/kook?pa...

Quote: Originally posted by crabnebula

Really, not too complicated. Air up high is cold, more lift. Air that is warm is often down low, less lift. Cold air is more dense therefore has more lift and you can down size the kite size.

I am leaving in a couple of days for the climb/ski/ride. It will be interesting to see how these principles work out in practice. The air at altitude is less than half as dense at sea level; however, if what you are saying also has a demonstrable effect, things may balance out.

Above 7000 meters it will be cold. Keeping the extremities warm will be a challenge. Messing around with kite lines and stuff will be practically impossible.

Last January I was winter camping near Harbin in China (near the Russian border). It was FAR too cold too even consider pulling out a kite. I cannot even say that I enjoyed myself. Repeating that debacle would be a heart break.

Anyway . . . THANK YOU everyone for weighing in on this issue. I have learned a great deal from reading these posts and hope that I will be able to add to this knowledge with what I experience.

Wish me luck