Kite Flying Log

MBK 1-Skewer Sled

Well, up went the little sled with the first thermal to pass through the reserve. The darn thing had a bad tendency to hang right so it needs adjustment. Never mind, trimming kites to make them fly better is part of the fun!

With the photoshoot over, thanks to my wife (May) with her digital camera, I let out some more line and flew the sled up around 10 meters (33 feet) or so for a while.

Partly due to its flying fault, the little sled collapsed a few times and eventually managed to lose a tail! The paper clip must have been jiggled like a tea bag at some point, and somehow the tail attachment loop found its way around the bend and slipped off. It's the first time that has ever happened.

Funnily enough, with the right tail gone, the sled flew much better! See how two wrongs can sometimes make a right, in kite making!

Stay tuned for how I fix the kite, and for descriptions of some much more successful flights!

Date: Fri Aug 17, 2007
Location: Old Reynella (vacant block)
Weather: Light to moderate breeze, variable
Kite(s): MBK 1-Skewer Sled prototype 1

Comments: It was getting a bit late, but there was some breeze, so I decided to quickly repair the sled kite and head off. I went past the reserve, but it looked risky with kids playing and kicking a football, so I headed back up the hill to the vacant block. Pretty soon I had the kite out and hooked onto the fishing line. There were no problems launching in the fresh breeze. It was a bit too fresh, as I discovered a tendency for the kite to hang left. Sure enough, each gust would send it looping left and losing height.

After bringing the kite in, I tied a couple of extra knots into the right-hand bridle line, with the free end of cotton from the knot. This little trick shortens the line just a fraction. Sure enough, the kite took off straight as a die on the next launch. Actually, there was still a small tendency to hang left with the stronger gusts, but it was very much better than before. With the take-off time noted, this was a real chance to break our duration record!

Soon, 50 meters (160 feet) of line was out. I had to stand in just the right spot to avoid any danger of a tree landing. This vacant block is quite a small spot to fly a kite! A few people walked past and didn't seem to notice the kite. The light nylon line must be nearly invisible from a distance—not to mention the kite itself if you happen to be right under it!

Gentle thermal activity was still around, as I discovered when the little sled soared up to a 55 or 60-degree angle from the horizontal. It can't make that angle in a steady breeze. Earlier in the day, five pelicans in a V-formation soared over our house and then on into the distance, without a lot of flapping! Great soaring birds they are.

A lightweight swivel would be handy to have on the line. The monofilament line is always very twisted from being wound onto the reel; this has the effect of twisting up the sled's bridle lines in flight. This effectively shortens the bridle, so the side flaps tend to collapse inward occasionally! But it's only a minor problem.

I saw a bird flying quickly toward us at about 10 meters (33 feet) up. It only spotted the line when about 5 meters (16 feet) away from it, hastily changing course to avoid a collision!

With the sun setting, the freezer bag plastic actually started to glisten. Particularly the tails, as they made a silvery glittery dance in the dying evening breeze. Ahem, excuse me while I wax lyrical ;-)

More down to earth, I put Aren's socks on for the sixth time, as he insisted on pulling them off in the cold evening air! Also, my duration attempt was in danger of being cut short as I struggled to keep the little fellow entertained while the kite moved around in the wind shifts and gusts.

Toward the end of the flight, the breeze smoothed out then finally died altogether. Winding the line onto the reel as quickly as I could, the kite touched down while still about 10 or 15 meters (50 feet) out. It was a new duration record of 38 minutes!

Date: Wed Aug 15, 2007
Location: Old Reynella (reserve)
Weather: Moderate to fresh breeze, variable
Kite(s): MBK 1-Skewer Delta prototype 2, Modified Baby Sled

Comments: There was plenty of wind about, so Aren and I went down to the reserve with two kites under the pram. I was hoping to break either the altitude record or the duration record or maybe both today!

First up was the delta, this time with a bit more bow held into the cross spar. Actually, kite geeks might correct me on that and call it a "spreader" rather than a cross spar. Anyway, in the ample breeze, the delta was soon laying out line into the sky. Being a bit tricky in gusty wind, the kite ended up on the ground a few times. Nearly every time, I managed to relaunch without walking out to it, as described in an earlier log entry.

Finally, it was quite high and I let the reel spin out to just past the 50-meter (160-foot) mark, let's say 51 meters. As I hoped, it got up to a very high angle once or twice—with the help of some thermal activity, I'm pretty sure. That was the altitude record broken, simply due to the very high line-angle which I estimated to be about 70 degrees. There was not much sag in the line at all, I might add. Let's see ... calculate, calculate ... that means the kite was about 48 meters (150 feet) off the ground, not even allowing for any line stretch!

When the wind got a bit strong from time to time, I discovered another of the kite's characteristics. It would start to loop very tightly, with its 4-meter (12-foot) tail forming a three or four-loop corkscrew shape. It seemed like when it got like this, the tail wasn't doing its job very well. The fix was to walk quickly toward the kite to depower it completely. Then it would recover and race away in one direction or another, before eventually climbing high again. Maybe using two or three shorter tails instead of one long one will fix this looping problem? It's definitely something to try later! It's easy to change tails on MBK kites.

After the fun of breaking the altitude record it was time to try the Baby Sled. Maybe the duration record would fall now, with the decent breeze up there filling the more stable sled kite. I haven't flown this for a while. Surprisingly, this little shop-bought kite felt like a bit of a dog after flying the delta! It took much more breeze to get up there, and (being a sled) tended to hang around the 30 to 40-degree mark in terms of line angle. It came close to breaking the duration record, but Aren was a very naughty boy and pulled out my yellow kite-bag and let it go in the breeze. This was just at the very moment I was trying to keep the sled in the air during a lull in the breeze! I ran forward and grabbed the bag, but that's all it took for the sled to hit the deck from about 5 meters (16 feet) up, unfortunately. Oh well, there's always another day.

Date: Wed Aug 8, 2007
Location: Old Reynella (vacant block)
Weather: Strong breeze, gusty
Kite(s): MBK 1-Skewer Delta prototype 2

Comments: The weather was blustery today, with about 50% cloud cover. Some of cloud cover was a bit dark, so I wondered about safety. Eventually, I decided to go out, as bluer skies were on the way from the northeast. The delta was popped in the pram, and off we headed to the reserve. Too many kids of a dangerous kiting-interfering age were there, so we continued on to the vacant block :-) Nothing against kids, but today I was doing some testing.

This time, the delta had some dihedral held into the cross spar with some cotton line tied across it. Let me explain dihedral. Looking at the kite's nose from the front, the sail is now gently bowed upwards instead of being perfectly flat from wingtip to wingtip. Some kites are built like this so they don't need a tail. In this case, I just wanted to cure the dreaded instability problems! Well, it worked great.

The kite quickly climbed up to a steep angle on the line. Soon, the turbulent breeze had the kite right across to the left, from where it usually doesn't recover. But this time, it hung there for a moment then gradually righted itself and shot back across the wind window. And it went up to the top then across to the right. Again, the recovery  was slow—and again and again. At last, we had a stable little delta handling a strong gusty breeze! Turbulence from the surrounding trees hit the kite repeatedly, sometimes making it feel like I had a large fish taking bites on the end of the line!

Having said all that, the wind was so rough that the delta still ended up on the ground many times. But its flying characteristics were so much better than before. What seemed to happen to this delta (and also the number 3) is that a sudden drop in wind strength causes a stall. The pointy wing tips tend to stall before the rest of the sail, so the kite drops a wing tip, rolls onto its back and then glides steeply to the ground. But now, with the dihedral, I could often slacken off the line, allowing the kite to glide free and right itself. It would then catch the breeze and take off again, up or across the wind window.

Would you believe, this little single-line delta is relaunchable! Yes, you just carefully pull it toward you while it's on the ground. The pointy tip catches in the grass and the kite pivots up on one spar. With care, you can keep pulling until it flops down again, with the bridle on the bottom. Further careful pulling will line the nose up into wind. Now, it's just a firm tug and the nose comes up and catches the breeze. This worked so many times, far more often than I had to walk out to get the kite. So cool—it's a single-line trick kite! I'm not sure that Aren, watching from his pram, appreciated the fun I was having!

The kite was now flying for 2 or 3 minutes at a time on the 17-meter (55-foot) cotton test line, sometimes reaching a 70-degree angle in the fresh breeze. What will it do on 100 meters (330 feet) of fishing line? Watch this space!

Date: Wed Aug 1, 2007
Location: Woodcroft (reserve near golf course)
Weather: Moderate/strong breeze, gusty
Kite(s): MBK 1-Skewer Delta prototype 2, 1-Skewer Sled prototype 1

Comments: It was a sunny and windy day, with some high and mid-level cloud cover. It was time to try a new flying location we found the other day. Into the car went three bags, each containing a kite attached to an appropriate tail for the conditions.

First up was the delta, which I had modified a little by trimming its trailing edge so it goes virtually straight across from wingtip to wingtip. It was a true delta shape now, whereas before it looked more like a diamond from a distance. This left the center spar protruding out from the trailing edge. With a fairly strong breeze now, I went with another approach regarding its balance. With all the paperclips removed from its tail, I made sure the bridle attachment point was still well ahead of the balance point. As it should be for all flat kites. Also, it now had a new 2.5-meter (8-foot) blue-plastic tail attached.

Even when out of the wind shadow of any trees, the air was very gusty. The kite alternated between hanging in the air with a slack line and rocketing straight up to a high angle with plenty of tension in the line. The old instability problems were still there whenever it got too far to one side however. The continuing saga of the misbehaving flat delta! I still have a trick up my sleeve though. We'll try it next time with a slight bow held into the cross spar by tying a length of cotton line across it. Like a bow kite, but just a tiny bit of bow. It could yet end up being a great little high-wind kite—rigid, light, and stable. Maybe.

Not wanting to waste any more time, I walked back to the car and got out the sled. This was a brave move. Will it survive this breeze? Will it survive the dogs that keep walking across this field with their owners? After untangling the twin tails and letting it fly, the little sled soared up several meters. Walking backward to keep some distance from the downwind trees, I let out more line. To cut a long story short, the kite had several flights, some of them quite high. All flights were terminated by the looping caused by too much air pressure. It was always to the left, so I added a paper clip to the right spar, for weight. It made no difference. Mmm. Aha, maybe I could adjust the bridle.

After a bit of experimenting I discovered small adjustments can be made simply by tying more knots into the existing knot which tied the bridle line to the kite sail. Each time the loose end of the knot was knotted again, the bridle line would shorten just a tiny bit. In fact, I overdid it and on its next flight the kite started looping to the right instead of the left when overpowered by the wind. OK, so lets shorten the other bridle line as well. As I was getting this adjustment just right, the poor little sled shed one of its bridle lines. Yep, it was an inflight structural failure—tested to destruction, as they say in the industry. Amazingly, the fluttering, broken kite continued to fly a meter (3 feet) off the ground for some time!

We didn't bother with flying the diamond today, after all.

When we got home, I discovered it was the sticky tape attachment point that had failed on the sled. It had simply split where I had cut a nick into it to stop the bridle line knot from slipping off. I might have to tie it without a nick after all. If the knot is tight enough it shouldn't slip off. We'll see!