Gliding - my random thoughts

[Kenny]

My wife gets bored with this stuff. I have these ideas rattling around in my head and I would like to discuss them with anyone interested.

First random thought - Kite size. The big question mark in my mind is the ratio of body weight to kite size for optimum gliding. I know that for a rider my weight (185 LBS) that a 12 M foil doesn't offer enough float. I started out last season with a 17M SilverArrow. It was good for gliding, but it didn't have a lot of depower, so I had to put it down when the wind was over 17 mph. I then went to a 19M SilverArrow 2. It had more depower and the float was unbelievable. However, the SA2 has a couple of weaknesses, it turns slow making loops more difficult and it's sheer size can be cumbersome.

Here are my ideas on the weight to kite size ratio (remember the projected area on a foil kite is higher than an LEI, so for example a 19M foil = 26M LEI, 15M foil = 20M LEI, 12M foil = 15M LEI).

12M foil/185 LBS = .065
15M foil/185 LBS = .081
17M foil/185 LBS = .092
19M foil/185 LBS = .103

10M foil/150 LBS = .066
12M foil/150 LBS = .08
15M foil/150 LBS = .10

This is not an exact science because with a smaller kite, you can work it aggressively through the air to maintain better lift (I have a video that shows Chasta going off the hillside at Skyline followed by me. Chasta is on a 10, but he flies it very aggressively to stay in the air, while I just make gradual adjustments to my 19M). Heavier riders are penalized by slower moving kites, so they have to upsize a bit. I am hoping that the 15M will be the perfect balance between fast turning and sheer canopy size to be an excellent floater and yet still retain the characteristics of a decent turning kite.

Next random thought - kite fabric - the more I have used Skytex 27 (the lightweight fabric used on the silver arrow) the more convinced I am that it is ideal for a snowkite. I was able to fly the Silverarrow in 5 mph wind and it is a freaking 19M. Imagine a 12 or a 15! The other cool advantage of the lighter fabric is that the kite would tend to just hang there after a funky gust or lull rather than twisting, stalling, or falling. We all know the wind in the mountains is funky, so having a kite that is more forgiving is awesome. The big problem is cost - Skytex is more expensive. Something like $300 - $500 more per kite. Not for every kite, but maybe for the largest ones...

Feel free to comment on any of the above.

Kenny

[MikE mAy]

i don't really have a comment so much as a question as i'm new to gliding. how does a LEI mess up the ratio equation? would you say you need more kite above you if it's a LEI, or is the style just changed a bit? watching jake and watching you- you both seem to fly the kite differently. you have different styles too though... do we just add the typical 2M to the foil kite size to reach the LEI size needed, or is there some other factor involved?

[windzup]

You need large enough kite to float your body weight, and a small enough kite so it can fly as fast as possible.

An important factor in any wings flight is speed. From paragliding we learned that speed is lift. From launching airplanes the instructors teach to power up while gaining speed down the runway, and keep the nose down until you hit the magical ground speed near 70 mph that creates lift and takes the plane up.

So, a larger kite will fly slower, while a smaller kite flies faster. Of course you need a larger kite to float your body weight. But the faster the kite is flying through the air... then the faster your groundspeed will be creating a faster airspeed. More speed is more lift.

Of course wind and terrain angle are the big factors.

So based on your numbers Kenny, it looks like if Chasta is on a 10m, us bigger guys should be able to do the same on a 12/13 meter? With a larger size offering even more float right?

Windzup,
Brian Schenck

[Kenny]

Mike,

An LEI has a smaller projected area than a foil kite. Bow kites tend to be flatter and closer to a foil. Let's just take the examples I gave. A 19M foil is roughly equivalent to a 25M LEI, a 17M foil = 21M LEI, 15M = 19M LEI, 12M foil = 15M LEI.

Jake does have a different style. I will have to film him this year so that I can indentify the differences.

Brian,

I think a rider our size can make a 12 or 13M kite work if he can generate enough speed. The practical difficulty at Skyline is that the hill is a bit too gradual and due to the western facing slope the snow conditions were often slushy or deep powder. So yes, a 12/13M will work, but you really have to get hauling down the mountain. I found that going off of the northside (Chasta's launch pad) that I had a difficult time clearing half the hill on a 12M. It felt like I would reach a certain point and then start to drop rapidly. However, that was over a year ago, so maybe I need to try it again and try a more aggressive technique. On a 17/19M, all you do is point your board downhill, go 50 feet, sheet-in and enjoy the view.

Kenny

[Poniboi]

WOW!!!! Brian puts it best you can fly any size wing all that matters is that you can go fast enough. Airspeed over a wing will create lift. Wind = airspeed so the more wind the more speed, smaller kite not bigger. I know 200+ pound kids flying smaller paragliders than 17M and 19M so I really dont understand this line of thought. Bigger kite less wind makes sense, bigger kite way slower landing speeds this I do understand. As for Chasta's aggresive flying again airspeed = energy, energy means soft landing and control on landing. I bet Kenny if you used a smaller kite for some more speed you might not need 17M and 19M paraglider and spend less time sorting you paraglider I mean kite out at the bottom of Bosco hill. I have a 38M Tandem Paraglider that I fly all through the weight range, it is all about how fast you fly and how you use the available energy.

[Kenny]

Poniboi,

I think I understand what you are trying to say.

I assume that your point is that with more speed, I could use a smaller kite than a 17 or 19M. I agree with you. However, the problem at Skyline is generating much speed on a hill that is less than 30 degrees. Of course, more wind will do the trick, but the difficulty with more wind is that it becomes really gusty at Skyline or Strawberry (not ideal for gliding). At the Point of the Mountain we often have steady 20 knot wind out of the South which makes it possible to fly a smaller paraglider like a 17 or 19 for that matter I have seen a number of pilots soaring on a 10 or 12M Speedflyer. At Skyline the most consistent and predominant winds are in the 10 - 15 mph range. So it makes it more difficult to make the smaller kites work. This year I hope to make a 15M work.

The real solution is for me to lose 30 LBS and stop eating so much ice cream! That way I could fly a 12M and float like a bird in the lightest of breeze.

Kenny