May 1, 2008 20:50 - Sled Kite Soars Before Rain Drops Stop The Show
Yes, rain drops stopped proceedings in a hurry this time, but not before a short and somewhat exciting flight!
Earlier in the day, there had been some rain, as the weather forecast had predicted. However, conditions were supposed to fine up later. Which they did. By the time we got out to fly, there were still large areas of cloud cover, but a fair amount of sunshine too. On arriving at the reserve near the school, the wind appeared to be picking up just a little. Good, maybe we'll get the first decent high flight with this new kite!
True to form, the orange 2-skewer sled mis-behaved at first. It was going to be a challenge to get it above tree-height. The lee-side turbulence of a dense line of trees kept collapsing the sled. At times it just fell to the ground, and at other times I managed to save it just centimeters above the grass. By the way, we were a fair distance from the trees! This kite is very sensitive to rough air.
A stronger puff of wind came through, and I found myself letting out line an arms-length at a time. Rocking fore-and-aft with my arm movements, the sled kite climbed strongly, finally above tree-height. Into the smooth air, it went straight up like a home-sick angel, heading for the ominously dark clouds not far above. After just a minute or two of sitting up there at a 55 degree or so line angle, I felt drops of rain!
Also, the wind picked up further, although it still seemed very light at ground level. As the sled slowly looped over to the right, the line went tight and started to buzz. Well, well, from 'almost too light to launch' to 'too windy' in such a short space of time. Actually, there had probably been a much faster flowing layer of air up there the whole time...
Anyway, with raindrops falling, I was not keen to repeat Benjamin Franklin's famous experiment. You know, the one involving a wet kite string and gulp lightning! The kite had to come down, and fast. Dropping the reel in the grass, I quickly moved towards the kite, pulling down the line an arm-length at a time. Yes, the kite came down just as quickly as it had gone up!
It soon became clear that a small rain squall had moved through. No doubt the local wind conditions were affected while it was in the area. The huge dark area of cloud moved off to the East as we headed home.
Wasn't that exciting, boys and girls? ;-)
May 4, 2008 19:50 - Sled Kite Towed High With Human Pay-out Winch
A pay-out winch is often used when towing paragliders or hang gliders into the air. Put simply, it's a drum with a braking mechanism, set up to deliver a constant line tension during the launch. The drum is mounted on a vehicle of some sort, which tows the aircraft into the sky like a ... kite. Exactly like a kite. If the driver goes too fast, or if the aircraft encounters higher wind speeds, the line simply pays out faster. This prevents the tension from getting any higher. What has all this to do with my humble sled kite? Read on...
We set out for the reserve near the school, despite signs that the wind was dying. We kite fliers must be an optimistic lot! On getting out of the car, there were still gentle gusts coming through so it seemed promising. Knowing that the tree line along the Western edge of the grounds often disturbs the air over a large area, I headed off for the far corner of the field. I dropped the reel about half-way out and simply pulled line off as I went. This is one of the nice things about a round reel as opposed to a simple wood block winder!
With the first gentle puff of air, the orange 2-skewer sled filled with air and rose tentatively into the air. It swayed slowly from side to side, in response to the stabilizing effect of its twin garbage-bag tails. The left tail had an extra bit, a loop of clear freezer-bag plastic. This was my attempt to correct a tendency for the kite to loop to the right when at the top of its wind range. The wind won't be anywhere near that strength today though, not even up high.
Walking briskly back towards the tree line, I let the line slip through my hand. If I felt some extra tension, I let the line pay out quicker. If tension died a bit, I held on tightly to keep the kite climbing. And climb it did, during this human pay-out winch launch! Soon, it was at about 1.5 times tree height, high enough to catch whatever slightly better air was up there.
Well, there wasn't really enough breeze to keep the sled up. But it was fun doing a bit of light wind flying, working to get the most out of every little gust which came through. At one point I noticed 3 little birds flying around in circles, which they sometimes do when feeding on insects that get caught up in rising air. Quickly I took a dozen or so steps to the left to position the kite where the birds were. If it was rising air, it was very weak since the kite didn't respond much. Now that's optimistic, trying to thermal a moderate-wind sled kite!
Altogether, I probably re-launched 3 or so times, before we gave up and went home. My wife May asked me whether I was making more kites with the same orange plastic, since she thought 'it looked like a bought one'! Yes, the rest of the MBK 2-skewer kite series, all 7 of them, will indeed be made with the same orange garden-bag plastic and black electrical tape spar caps! If you subscribe to the MBK newsletter, you can make them too, one every month.
May 9, 2008 22:53 - New Diamond Kite Flys High from Tiny Back Yard
The new 2-skewer diamond kite has just been finished, but it doesn't fit under the pram. So, it's either hop in the car with the kite in the boot, or... Fly from out of the back yard! Always a bit exciting since danger lurks everywhere. The clothesline, the swing set, the neighbor's yard.
With just the occasional gentle gust moving the smallest branches and twigs on the surrounding trees I thought it was worth a shot. Confidence wasn't super high since the plastic sail is not exactly feather-light, and a fair amount of wood glue was needed to join and reinforce the spars. At first, it didn't want to climb at all, so I edged the towing point forward a centimeter or 2. That did the trick.
After a bit of fancy working of the line as some gusts blew through the yard, I managed to get the kite above gutter level. From there, if the breeze persisted for a few more seconds, the kite would climb quickly several meters more and escape the erratic movement of air around the house.
At 2 or 3 times the height of our roof, the MBK 2-Skewer Diamond behaved beautifully! With just a very modest amount of breeze, it would fly steadily and at a very good angle. Around 60 to 70 degrees! Maybe it was getting some help from warm air rising off our roof at times.
At one stage I was amazed to see it nearly overfly my position in the yard, like a delta! Not wanting it drifting off to who knows where, I pulled some tension into the line and brought it down vertically. There was no longer any horizontal movement of air through the yard, so it ended up at my feet.
This was fun, getting 2 decent flights, several minutes long each, from a launch area roughly 3 x 4 meters in our tiny back yard! A more controlled, satisfying experience than trying to fly one of the single-skewer designs and having it weave all over the place and dash itself against the roof from time to time!
We might take both 2-skewer kites out next time we go to a large reserve. It will be very interesting to compare the diamond and the sled.
May 14, 2008 14:18 - High Flying Diamond Kite - School Kids Gawk
Stronger winds and generally more wintery weather was forecast for tomorrow, so we slipped out just as soon as the wind started to pick up. That was just in case it got too strong later on! Down at the reserve near the school, the sun was shining and the wind was still fairly light, but with fresher gusts that moved whole tree tops. A nice change from the almost dead calm conditions of the last 2 days.
The diamond flitted around down low for a couple of launch attempts, before a stronger gust sent it soaring. It was on our longer line.
Recently I had measured out 150 meters and tied a small loop into it to mark that length. This will place the kite close to the legal ceiling of 400 feet above ground level, at high line angles. You might be more fortunate in your country, with much higher ceilings, if any at all!
The diamond kite continued to climb as I let line come off the reel. At one point, by holding the reel side-on to the kite, and feeding the line through my hand, the line actually fed itself off the reel. A short loop did 360s around the rim of the reel as the line payed out. You can't do that with a winder! On the other hand, that might depend on exactly how you make the winder... I feel an experiment coming on!
With about 100 meters of line out, there was a lot of sag so I gave the kite a chance to climb some more. Even so, it settled out at between 40 and 50 degrees from the horizontal. Thermals were coming through which caused the kite to rise and sink from time to time. With a bit more wind to pull the line tight and generate more lift over the kite, it should still make a 60 degree angle on 100 meters of line. That length of 20 pound line might be the practical limit for this kite design.
We had to get back home, so we began pulling down the kite. My wife May had a turn, while I wound onto the reel. Even Aren, just 2 years old, had a go, sitting in his pram! He managed to successfully pull down several meters of line, hand over hand, before letting go. As toddler kite fliers do! Never mind, I had the reel, winding on the loose line.
With the kite down to 20 or 30 meters, a line of school kids appeared. Were they just watching, or had they been sent outside with some activity in mind? We hurriedly kept pulling the kite down, then got out of the way. A short while later, the kids started jogging around the perimeter of the field, not of their own free will I suspect!
Although it was a short outing, it was nice to see the new MBK diamond kite strut its stuff on a decent length of line. In much stronger wind, it might need another loop of tail, but for general flying it seems we've got it about right.
May 15, 2008 13:37 - More Diamond Kite Backyard Antics
Although cloud cover was building up, there was still sunshine and a moderate gusty breeze blowing around the house this morning. With Aren happily installed on the swings and unable to get out, I made a snap decision to take the MBK 2-Skewer Diamond outside for a fly! After a few launch attempts, the kite finally made it into relatively smooth air above the house.
Backyard flying is a bit of an art-form, requiring concentration and quick reactions when the kite wanders. But it's a lot of fun! Maybe it's the risk, the danger... ;-) I'm sure I heard a loud chuckle from a neighbor over the road at one point. That was when the kite first rose up and, probably against their expectations, parked itself in the air way above our roof - nice and stable!
The orange diamond had at least a couple of flights of several minutes each, out of our side lawn. That's an area about 4 by 10 meters (13 x 33 feet) Our roof gutter on one side, a row of rose bushes down the other and a peach tree right at the far end! No problem... well the tail did snag for a moment on the top of the peach tree, but the kite pulled and freed itself. Also, there was a close call when a sudden wind shift took the kite over the neighbor's roof - and then it looped!
Amazingly, the kite reached a 90 degree angle over my head while at about 1.5 times roof height. Warm air billowing up from the hot roof perhaps? Then it floated off downwind, took up tension in the line and started acting like a conventional diamond kite again.
A lot of footwork, pulling in and paying out goes on with this kind of flying. The wind down low is never constant, even if the kite is out of turbulent air from all the obstructions such as fences, trees and houses. Small changes in wind direction force you to change position so the kite stays out of neighboring property. You might have to reel in to keep it airborne, waiting for another gust to come through. A bit of tension in the line allows you to let a bit more slip through your fingers to gain some more height. And so on!
All this time, Aren was still around the corner out of sight, on his swing. 'More', 'More', 'More' he chanted at one stage. Did he want more action from the kite, or just another push?
May 22, 2008 20:14 - MBK Diamond Kite - Hooked On Backyard Flying
With the weather and other factors, there hasn't been an opportunity to fly for a while. However, this afternoon a sunny period with a gentle breeze outside tempted me out for another spot of... backyard flying! Who would have thought that attempting to fly a kite out of a small backyard could be mildly addictive!
The breeze was pretty marginal actually, and it took many attempts to get the kite far enough above gutter height to catch smoother air. I shifted the towing point back just a smidgeon (1 smidgeon = 2.5 tads) to extract the best light air performance from the kite. Patience paid off, with the orange 2-skewer diamond eventually sailing high above the house. I bravely let out about 15 or 20 meters of line! I think a diamond with dihedral is actually very good for this kind of thing due to its predictability. Even so, some fancy footwork was necessary at times, to keep the kite within our property.
Several flights like this were made, and nearly every time the diamond flew at very high line angles. Like 80 degrees or so! However, there were signs that the kite was in rising air. Maybe the dark tiled roof was a weak but continuous thermal source. Fun fun fun! As the kite came down each time in the lulls, it was easy to reel it in and fly it right down to land just in front of my feet.
May 23, 2008 20:57 - Skewer Sled Kite - New Simplified Instructions
I've recently begun re-doing the construction pages for the 1-skewer kites. This is because the last 10 months or so have taught me a thing or 2 about making kites from bamboo and plastic. Take a look at the new MBK Sled Kite instructions. Accuracy is more assured, and tail attachment is very easy, without sacrificing the ability to change tails later if you want to. No paper clip is required for attaching the flying line, which saves a bit of weight. Taking the photos for these instructions has resulted in Skewer Sled number 3.
There might be very small changes to my construction method in future, but it's reached a point where I'm fairly happy with it. All the MBK designs, both 1 and 2 skewer, can be made in basically the same way. It might be a few weeks before all the instructions get updated, of course!
The aim has been to get the best performance for the least money and with an absolute minimum of tools.
Anyway, back to the new sled kite. The weather was looking ok outside this afternoon, so Aren and I headed out to the Old Reynella Reserve. Leaves in the tree tops were moving around quite vigorously from time to time. Looks good! However, the spars on this kite were from the heavy batch so the little sled struggled to stay up in the very light and variable air.
Finally, a good long tow across the reserve got the sled kite above tree top height. From there, it had no trouble climbing higher, and I was able to let out all 50 meters of the test line. The little sled flew great, nice and stable with no real tendency to hang left or right. There is something to be said for carefully hand-selecting spars!
Line angles varied from about 30 to 45 degrees. Ok for a tiny sled on 50 meters of 20 pound line. It would do better on 3kg (8 pound) fishing line. Aren and I had to shift our position from time to time as wind shifts came through. Why? To keep the kite away from un-landable areas like tall trees or the kids' play equipment! It's only a small reserve.
There were a few rough patches in the airflow which collapsed the kite a few times. The kite would then loop round and round, losing height rapidly before inflating again. Interesting, since the kite was flying well above tree top height.
Nearing sun-down, it was clear that the sled kite was enjoying itself up there and had no intention of coming down! So we brought it down slowly, winding line onto the winder. The rays of the setting sun accented the curve of the sail and illuminated the dance of the twin tails. Oops, forgot the camera... Aren had some fun pulling in the first meter or 3 of line. Being only 2 1/2 years old, that was enough for him before he handed over to me. All in all, a great test flight!