Paper Kite Posts—Sled

(Paper Spars)

It's an archive of sorts, although there are no dates and times. Kite flying is timeless, don't you agree?

I trust there is plenty in here to educate, inform, and often entertain!

These short flight reports once appeared as posts in the site-blog page, although that page is no longer present on this site. Below, the latest posts come first. Just scroll down and stop at any heading that appeals :-)

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Paper Sled Kite

Paper Sled Under Attack

The first task was to try and trim out a tendency to loop to the left.

Another manifestation of the problem was bobbing much further to the left than to the right. Retying the bridle to slightly shorten one line fixed the problem nicely.

Paper Sled Overcome

As in, the little Paper Sled got overcome by sheer wind speed today!

It seemed like a good opportunity to get in another long flight. The breeze was pushing bushes around in the backyard, which would be no problem for the Paper Sled. However, the air was forecast to be much stronger toward the middle of the day. So I wasted no time and got out to a large field, before 9:30 am.

For some reason, perhaps some tangling near the bridle knot, the sled had a tendency to loop to the left. Gaining height was a struggle since the gusts were near the top of the kite's range. There was too much pointing sideways to make much headway into the sky! Several minutes went by, as I let out line and found a suitable spot to anchor the thread.

To cut a long story short, I spent plenty of time walking back and forth, relaunching the kite—and mending a break in the flying line at one point.

Eventually, I tried a small ribbon of Tyvek knotted to an outer tail streamer. The Paper Sled consequently maintained enough balance to stay quite high for some time, unattended. Unfortunately, the wind speed had continued to build until the thread parted once again. This cut the flight time to just seven minutes.

The beginnings of a small thunderstorm were gathering almost directly overhead. So it was definitely time to pack up and get out of there!

Disappointingly, today's busy outing only returned a small amount of loggable flight time. There's a club kite-fly on tomorrow, so we'll try again then, at the same field.

Finally, the Right Sled

Just on impulse, I searched the Web for high-wind sled-kite designs.

One in particular seemed very promising, having a huge claimed wind range. Now, with everything in 40 gsm paper, my version was not going to match the claims; but would it do better than my several attempts so far?

The design was an old Allison 2-sticker. My current designs were quite similar, right down to the angled longerons. But perhaps this classic one was tuned to perfection.

After getting busy with fresh sheets of paper, scissors, tape, and polyester thread, a new sled was soon ready to fly. I had a good feeling about this. For one thing, the flying area was somewhat less than my original sled, which would help the thread stay in one piece at the upper end of the wind range. The classic version flew tailless, but I retained a 50 cm long curtain of 1 cm ribbons to keep that weighty sail from swinging around too much.

Down at the park, the breeze was initially too light to make much progress with testing. But then, with distant rain clouds approaching, the wind whipped up. Gusts were well into the 20s in kph, moving the treetops. And the little sled loved it!

For quite a few minutes it was a pleasure to watch and feel the sled surging around on more than 30 meters (100 feet) of the thinnest cheapest polyester sewing thread. It held. The design is nailed. I thought it was nailed before, but the original kite was hindered by an excessively long and heavy tail that was needed to keep it stable. Also, there was the problem with frequent line breakages due to too much line tension. It's all good now, although tangles and knots could still part the line in fresh wind.

Paper Sled Touch-n-Goes

Student pilots do it—touch down, apply throttle, and take off again.

The Paper Sled did something similar, several times today. There was a gusty and gutsy breeze from the east, pushing through the trees at close to 20 kph and flowing over the top at 30 kph or more during gusts. The kite would sometimes contact the grass nose-down, only to rotate a bit to one side and promptly climb away again.

Once again, the polyester thread flying line was tested to its limit. The thinnest portion, which was attached to the kite's bridle, gave way a couple of times.

I ended up getting rid of the thinnest thread and tying the kite onto the somewhat stronger thread further back. It was still ordinary polyester sewing thread, but at least one size up from the very thinnest available. No line breaks occurred from then on.

Funnily enough, it was the line of trees getting in the way of the breeze that often kept the kite in the air!

Time and again, the sled would circle tightly to one side or the other, driven to instability by the air pressure. However, after losing enough height, the slower air in the wind shadow would allow a recovery—just in time for the kite to move back up. With the worst of the gust having moved off downwind, the kite would climb to full height once again.

Occasionally, a break in cloud cover would bathe the entire field in sunlight. Moments later, the kite would take advantage as the slightly warmed air drifted upward. This was evidenced by higher-than-usual line angles, despite a slight drop in wind speed. The effect was a bit harder to pick with a heavy 40 gsm paper kite, but it was there.

Some of the touch-n-goes consisted of a brief sweep of the tail against the grass!

Finally, a much longer flight of 30 minutes was recorded. The sled managed to recover height many times without any paper actually touching the ground. After adding a little more tail, I'm hoping the remaining hour of flight time for certification can be achieved in just one or two flights. Perhaps this will be down at the beach, in smoother winds.

Paper Sled Logs Flying Time

That's what it was all about this morning. Trying to edge toward the 3 hours of total flying time required for certification.

Why 3 hours? That's to expose the design to several separate flights, manual handling, and a range of weather. This will ensure that future builders will have a good chance of getting a reasonable amount of flying out of the kite.

The wind range being experienced at the nearest weather station was just perfect for the sled. Down at a local reserve, the treetops were moving about. It was going to be another gusty time with wind speeds varying all over the gentle to moderate ranges.

After a couple of short flights, it was clear that flying on the longest possible line would be a good idea. Kites made from A4 paper come down in a hurry during lulls! So, I eventually reached a far corner of the grassy area which allowed a good 90 meters (300 feet) of thread to go out. This also made allowances for retrieving the kite should the thread break!

After a full ten minutes, the sled descended to the ground—only to relaunch itself once again, shortly after. Up high, strong thermals were pushing the kite hard with almost-fresh air speeds. Also very noticeable were large changes in the wind's direction as air got sucked away to the left or right. A patch of slower-moving sinking air nearly grounded the sled once more, but it clung on, just clear of the grass before making a spectacular climb. This flight lasted for 15 minutes.

Finally, with the average wind speed seeming to drop a little, a lull brought the kite down after just 5 minutes. I didn't intervene; that's against the rules ;-)

It was time to call it quits. A useful 25 minutes of flight time had been logged.

Paper Sled Nearly Nailed

I wouldn't call it "nailed to the sky" as such, but...

The Paper Sled is on its third prototype. After today's flying outing, it would appear the design is 90% there. "Nearly nailed" in other words. The next 40 cm tall Paper Sled will be done in colored paper, with just a few minor tweaks to ensure that it gets through its upcoming certification flights. I'm serious about this stuff ;-)

The aim is to produce real sparred kites that use no spar material except ordinary copier paper and sticky tape. Today saw a wonderful proof of concept.

As I pulled up at a small grassy reserve that hadn't been flown at before, the breeze looked ideal with treetops being ruffled. Being rather heavy for their size, these paper designs require more than a light breeze to stay up.

Initial attempts at flight were disappointing. The kite was flying stable but refusing to rise more than a meter or two over the grass. Thoughts followed, of having to abandon the entire idea of copier-paper kites. But then, I moved over to a more open section of the reserve, where wind blew through with less interruption from trees and houses.

Success! The dodgy-looking kite, fashioned from pieces of obviously used A4 paper, began to soar high over the grass. Now well above tree height, the small paper kite drew the polyester sewing thread almost taut. In the strongest gusts, the thread flying line stretched a little, but held.

After a while, there was around 60 meters (200 feet) of thread in the air. The small sled moved around quite a lot in the gusty gentle-to-moderate breeze. The tails rustled furiously, although they remained undamaged. Perhaps 20 minutes later I brought the kite down. Wonderful!

Next in the series will be the Paper Diamond.

Paper Series Lifts Off

There were perfect conditions for testing the Paper Sled today.

This sled is the first of what is hoped to be a series of eight or so designs. All to be made from paper and sticky tape and flown on ordinary polyester sewing thread. No straws, bamboo, or anything like that will be used! It's a strictly paper-and-tape project.

The aim for every kite will be to fly the gentle and moderate wind-ranges, up to 200 feet, and durable enough to last for 3 hours of total flying time each. Talk about a design challenge!

Today's sled managed to fly in winds toward the high end of gentle, approaching 20 kph. However, its wind range was narrower than even a small kite should achieve.

I won't let on just how the paper-only spars are made just yet, but the current ones had ample strength and rather too much weight it seemed. This was easily fixed by trimming down the dimensions.

The tails worked but needed more effectiveness in fresher breeze strengths, so they are getting wider.

I tried paddles on the ends of the tails to make them much more effective. However, the extra paper on the ends spun like windmills, twisting up the ribbon tails and occasionally joining them together as the kite flew! Toss that idea, I thought.

So, I'll shortly be whipping up another kite with slimmer spars and wider tails. This shouldn't be too time consuming when it only involves a few sheets of paper.

 

 

 

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