Date: Wed 29 Aug 2007
Location: Old Reynella (reserve)
Weather: Very light breeze, thermals, warm and sunny
Kite(s): MBK Sled Kite prototype 2
Comments: Just a bit of breeze out there, but that's enough for an MBK Sled! Down to the reserve we went, only to find barely any movement in the tree tops. One of those 'thermal-only' days again. The sled performed better after the alterations I did, but still pulled to the right during the stronger gusts. Oh well, we'll just take it home and have a closer look. Maybe one bridle attachment point is just a fraction higher than the other, maybe one spar weighs a bit more than the other. Or all the above.
Adjusting the bridle line length on one side is not working for this kite for some reason. That said, we still had a pleasant time lofting it up to above the tree tops as each wind cycle came through. Maybe 30 meters or so of monofilament line let out. I even managed to ground-launch it several times, which is a bit tricky with a floppy sled kite!
Date: Mon 27 Aug 2007
Location: Old Reynella (reserve)
Weather: Strong gusty breeze, almost no clouds
Kite(s): Modified Baby Sled
Comments: With a bright sunny day outside and the trees all bending over in the strong breeze, it was time to go out and break the altitude record at the reserve. Rushed out to the shed, only to find that my little high-wind delta had a broken spar. It doesn't take much to break bamboo skewers unfortunately. It must have taken some weight in an awkward spot while being transported in its plastic bag.
So, Plan B. The Baby Sled! Not a great flyer, but at least it's strong. All 3 of us were soon at the local reserve. We headed upwind, parking the pram near the tree line. Soon, 50 meters were out and I nearly burnt my fingers on the line. Conditions were pretty wild, with the sled unable to gain much height. Not due to lack of wind of course, but rather, the opposite. Looping, looping, diving, swooping... Right on the edge of it's flying envelope.
Walking backwards, I headed for a gap in the trees on the upwind side of the reserve. Meanwhile, there were numerous close calls with the trees on the far side of the reserve! I actually laid the line across a shorter tree at one point, but eventually managed to fly the kite off it again. A few times, the long center tail would drape itself against the leaves of a taller tree, before I backed away and got the kite airborne again. This is called flying the local reserve on the very longest line possible!
The best angle the bright green little sled managed was about 25 degrees, very briefly. That works out to just over 40 meters of height, which is currently short of the record by quite a few meters. However, I did break the record for 'Longest Amount Of Line Let Out', at just over 100 meters! Someday I will have to get around to testing the actual stretch on this line. In strong wind, the distance out to the kite might be affected more by line stretch than by line sag!
All in all, it was a fun flight with a lot of re-launches from the grassy ground. It made me think that perhaps most single-line kites are re-launchable from the ground, with care and a little skill. One of these ground launches shocked an unsuspecting person walking along a path near the edge of the reserve! There was no flyer in sight, since I was lurking in the shadows of some trees more than 100 meters away. The line was nearly invisible, being 3 kg monofilament fishing line. And then this bright green THING springs into the air and swoops around like a demented budgie. That's 'budgerigar' if you are not from Australia!
Just to give you an idea of how strong the wind was, at one point the pram started off across the grass on a starboard tack. With my wife yelling at me, her voice disappearing downwind in the gale, I quickly ran after the pram, with the kite still in the air. Then I then returned to my original position to avoid getting the kite too close to the trees. A few minutes later, with both brakes on, the pram started off again! But it only got a meter or 2 this time.
It was obviously time to bring in the kite. For one thing, it was my turn to spend some time with Aren on the play equipment... So I started winding in, sometimes with the kite in the air, sometimes with it on the grass. With about 40 meters to go, I swapped child minding duties with May, while she continued flying and reeling in the kite. End of (unsuccessful) record attempt.
Date: Wed 22 Aug 2007
Location: Old Reynella (reserve)
Weather: Light breeze with thermals
Kite(s): MBK Skewer Sled prototype 2
Comments: The MBK Sled number 2 was just completed, mainly to provide photos for the How To Make A Sled Kite page in the How To Make A Kite section of this website. Time to take it out for a test, and also get some nice shots of it in the air, to finish off the How To.. page. Well, up it went with the first thermal to pass through the reserve. 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 photo shoot over, thanks to my wife May with her digital camera, I let out some more line and flew the sled up around 10 meters or so for a while. Partly due to it's flying fault, it 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. First time that has ever happened. Funnily enough, with the right tail gone, the sled flew much better! See how 2 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 17 Aug 2007
Location: Old Reynella (vacant block)
Weather: Light to moderate breeze, variable
Kite(s): MBK 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. Went past the reserve, but it looked risky with kids playing and kicking a football, so headed back up the hill to the vacant block. Pretty soon I had the kite out and hooked onto the fishing line. No problems launching with the fresh breeze. 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 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, 5 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, and 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 inwards occasionally! Only a minor problem.
I saw a bird flying quickly toward us at about 10 meters up. It only spotted the line when about 5 meters 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 6th 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.
Towards 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 out. A new duration record of 38 minutes!
Date: Wed 15 Aug 2007
Location: Old Reynella (reserve)
Weather: Moderate to fresh breeze, variable
Kite(s): MBK Skewer Delta prototype 2, Modified Baby Sled
Comments: Plenty of wind about, so Aren and I went down to the reserve with 2 kites under the pram. 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, it 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 nice and high and I let the reel spin out to just past the 50 meter 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. With not much sag in the line at all I might add. Let's see... calculate, calculate ... that means the kite was about 48 meters 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 its characteristics. It would start to loop very tightly, with its 4 meter tail forming a 3 or 4 loop corkscrew shape. Seems 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 de-power it completely. Then it would recover and race away in one direction or another, before eventually climbing high again. Maybe using 2 or 3 shorter tails instead of one long one will fix this looping problem? 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. 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 up, unfortunately. Oh well, there's always another day.
Date: Wed 8 Aug 2007
Location: Old Reynella (vacant block)
Weather: Strong breeze, gusty
Kite(s): MBK Skewer Delta prototype 2
Comments: Blustery weather today, about 50% cloud cover, some of it a bit dark so wondered about safety. Eventually decided to go out, as bluer skies were on the way from the north east. Popped the delta in the pram and headed off to the reserve. Too many kids of a dangerous, kiting-interfering age were there, so 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 wing tip to wing tip. 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 up to the top, then across to the right. Slow recovery again. And again and again. At last, a stable skewer 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 towards 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. 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 2 or 3 minutes at a time on the 17 meter cotton test line, sometimes reaching a 70 degree angle in the fresh breeze. What will it do on 100 meters of fishing line? Watch this space!
Date: Wed 1 Aug 2007
Location: Woodcroft (reserve near golf course)
Weather: Moderate/strong breeze, gusty
Kite(s): MBK Skewer Delta prototype 2, Skewer Sled prototype 1
Comments: A sunny and windy day, with some high and mid level cloud cover. Time to try a new flying location we found the other day. Into the car went 3 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 wing tip to wing tip. 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 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 a great little high-wind kite. Rigid, light and stable. Maybe.
Didn't want to waste any more time, so I walked back to the car and got out the sled. 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 backwards to keep some distance from the downwind trees, I let out more line. To cut a long story short, it had several flights, some of them quite high. All flights were terminated by the looping caused by too much air pressure. Always to the left. Added a paper clip to the right spar, for weight. 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, in-flight structural failure. Tested to destruction, as they say in the industry. Amazingly, the fluttering, broken kite continued to fly a meter 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. Might have to tie it without a nick after all. If the knot is tight enough it shouldn't slip off. We'll see!