December 1, 2008 11:24 - Little Rok Kite Flung About In Fresh Wind Thermals
Time to update some of those embarrassing old YouTube movies on the site! First up is the 1-Skewer Rok page. Looking outside, the wind seemed to be fairly fresh. Not a problem for the little Rok, which likes a good breeze as long as there is sufficient tail attached! Armed with kite, 50m flying line and camera, we set out for the reserve near the school. Combining keeping the family fit with web-site work!
After arriving and getting the Rok in the air, it became apparent that the average wind strength wasn't as fresh as it seemed back home. Instead, it was a taste of the approaching Summer, with wild thermal activity and an almost clear blue sky. A little mid-level cloud was beginning to build in the West. The insects were out in force again, buzzing the trailing edge of the kite whenever it took to the air.
It was actually a bit difficult getting some decent video. The kite kept getting knocked around by huge gusts from all directions. On a short line for videoing purposes, the kite kept ending up on the ground so I ended up taking 6 separate movies! Usually, it would get booted overhead in a sudden gust of lifting air, which would leave it floating down on its face before nosing into a dive all the way to the ground.
Warning: skip this paragraph if anything remotely technical makes your eyes glaze over! :-) During its long dives, giving the kite more slack line did nothing to help. It was in model-plane mode, being held in a steep dive heading more or less upwind, and flying at a very low angle of attack. The usual factors which keep a kite stable, upright and 'kite-like' were not in play. I found that it was possible to get the kite out of the dive only by pulling in line quickly enough to get some real tension on it. This forced the kite into flying at a higher angle of attack, where-upon it suddenly became a kite again. Tail, towing point and dihedral all combined to cause the kite's nose to seek an upward and upwind direction.
With some reasonable video footage in the bag, it was time to let out some more line and just fly for fun. It was still hard though, with the extreme variations in wind speed continuing to throw the Rok into long dives. Wind direction shifted around spectacularly as well. A sure sign of large thermals! Many times, I had to pull the kite in almost to my hand as the wind speed died off, before letting out line quickly again in the next long gust. Several times it was clear the little kite was struggling against sinking air, with low line angles yet plenty of tension. Eventually, I got all 50 meters of line out. Whew!
After winding in the kite, we spent some time with little Aren on the play equipment nearby. We watched as another flight fanatic came out to fly - a guy with a small electric-powered r/c plane. I didn't fancy his chances in the rough air, and sure enough he had a tough time keeping it up there!
Next video might be for the 1-Skewer Delta. It'll need some smooth light winds!
December 7, 2008 22:23 - 1-Skewer Delta Kite Dances With The Moon
Well, that's waxing a bit poetic, but the Moon certainly popped into the view-finder a few times while I took some video of the little Delta kite today. I have been taking down the old YouTube videos of various kites and updating them with new footage in my standard video format. That is, using the player you can see on any of the 2-Skewer kite pages.
With gusts of fresh wind blowing through the reserve near the school I knew it was going to be a bit of an exercise to get 20 seconds of good flight out of the kite. This tiny delta is a decent light-wind kite, but doesn't have a great wind range. However, with an extra length of tail in my pocket, I was going to give it my best shot!
Sure enough, after the first launch, the kite simply looped tightly half a dozen times before contacting the ground again. Soon, it was up again with the extra tail attached. By the time I had the camera sorted out, it managed to record about 10 seconds of the kite flying sideways near the ground and finally coming to rest. Persistence, persistence...
Moving across the field to get further from the upwind line of trees, I tried yet again, with even more line let out. Plus full optical zoom on the camera so the kite would not be a dot in the frame! This time, the kite stayed up for more than half a minute and some decent flying footage went 'in the the can'. However, it was only on my next and last video that I noticed the Delta flying past the Moon several times. Something of a coincidence, considering that both wind direction and flying angle of the kite have to be just right for that to happen! Not to mention the Moon being visible at all...
With website business out of the way :-) it was time for a bit of recreation. I used some of the strong gusts to quickly let out line. In no time, all the 50 meters on the small winder were out, and the Delta tore up the sky, trying to get above a 40 degree flying line angle. A lot of its time was spent dashing sideways in the relentless wind, so I don't think it ever got above about 45 degrees. Still it was fun to get the little Delta up once again on 50 meters of line. Our 50 meter lines are 20 pound breaking strain, but the 1-Skewer delta would actually be much happier on mono-filament of less than 8 pounds strength.
Walking downwind back to the car, the pace of walking dropped the kite into a more comfortable zone, and it floated about like the light wind kite it was designed to be.
December 13, 2008 23:21 - MBK Dowel Sled Kite - First Prototype Flies
That's a bit pompous isn't it - the word 'prototype' is more appropriate for a shiny new aircraft than to a piece of plastic with 2 sticks taped to it! Never mind. Without actually copying any existing designs exactly, this first flight of the new Dowel Sled was going to be interesting.
Before going up to the vacant block, I briefly tried the sled out in our very small back yard. The gusts blowing around the house were chaotic and a bit fresh, but the Sled did seem reasonably stable. Without tails! This is a vented design, for a change. In fact, I'm aiming to make the entire Dowel range of kites tail-less. Even the Diamond, which is coming up next in January. Gulp.
Up at the vacant block, the Sled soon took to the air on our spanking-new 50 pound Dacron line. Soon, it was clear that both the location and the gusty fresh wind were making things difficult for the kite. After all, I had designed it as a light wind kite. The Sled would climb away briefly after each launch, before flying sideways or promptly collapsing when hit by a stronger gust or a bit of rough air. I persisted, trying to get a feel for the kite's flying characteristics despite the difficulties.
This Sled will make a fine light-wind kite, although dowel is definitely inferior to bamboo as a spar material. Hence, if made with the same sail material as the 2-Skewer Sled, it might not actually be much better in light wind. It will be interesting one day to do a side-by-side comparison of the 2 kites.
As noted in the construction page on the website, I'm going to make a second kite soon. The side flaps will be shorter to make it less collapse-prone. The wide and wonky vent will be replaced with 2 smaller ones that will hold their shape better. Finally, the shorter flaps plus leaving tape off the vent perimeters should save a little weight. Not much, but every bit counts in a light-wind design!
Even so, I doubt I will be able to resist giving the original kite another fly if the wind calms down a bit over the next few days...
December 15, 2008 09:26 - Dowel Sled Struts Its Stuff
Well, I didn't think I would blog another flight of the first Dowel Sled prototype, but it flew so well yesterday! Later this week a number of improvements will be incorporated into the design, the construction page will be updated, and we'll get some video footage.
At the Holden Hill reserve off NE Road, the spots of rain and small wind squalls had given way to sunshine and light-to-moderate breezes. Perfect! As expected, the Sled gave a bit of trouble low down where the air was rougher. Collapsing, re-inflating and occasionally falling like a stone. All the MBK Sleds like smooth air! However, after working the line a bit and gradually getting more line out, the Sled was coaxed up above tree-top height. The trees are around 20 meters (70 feet) tall here and the reserve is small, so some fancy footwork was required sometimes to keep the kite away from leaves and branches.
A giant cumulus cloud came overhead, sort of like the space-ship in the film Independence Day! My guess was that there were large areas of lifting air underneath it. Despite only having room to let 30 meters (100 feet) of line out, the big Sled did go almost overhead several times. The kite got the attention of a number of birds too. Let's see... One little chirping bird hunting for insects in the warm rising air, 2 more small but fast birds who did a large 360 all around the kite (flying in close formation with each other!) and an Ibis that flew past searching for lift.
Also, a small kid yelled 'Wow! Look at how high it is now!' :-) No, it wasn't our Aren, he's seen it all before...
December 17, 2008 16:02 - Dowel Sled Kite MkII Is A Beauty!
Session number 3 in a frenzy of Dowel Sled Kite flying! I just finished the revised Sled design earlier today. With very light winds and the sun coming out between occasional rain showers, it was as good a time as any to put up the new kite. Down at the Wilfred Taylor Reserve we ran the usual routine. First, wifey takes a few launch shots, then she hands the camera to me while Aren has fun on the play equipment. Finally, with a bit more line out, I take a few movies to get a nice 20 second clip for the web-page.
Must say the kite fully performed up to expectations. It didn't take much breeze to get it climbing, and those double vents helped keep it quite stable as long as the air was smooth. Some of the movie footage included a rather impressive cumulo-nimbus cloud in the distance - maybe that will find its way into the final clip!
My expectations included seeing the kite fold up and plummet to the ground. That's what Sleds do from time to time! Perhaps light wind sleds are particularly prone to this. Eventually I will be doing fresh-wind versions of all the Dowel kites and 2-Skewer kites. It will be interesting to see how the fresh-wind Sled holds up.
Might leave it there for now. Next time we get out, perhaps the Sled will soar to 400 feet! If I can keep it inflated...
December 19, 2008 21:45 - Of Sleds And Thermo-Nuclear Thermals
Sled kites and thermals don't mix. Today, for the last time I think, it was proved yet again. Down at the Wilfred Taylor reserve, the prevailing breeze was quite light. At times, not even enough to keep the light-wind Dowel Sled in the air! And yet, the thermals lifting off from the area were savage.
Sudden, very fresh breezes would come tearing through, ruffling the upper branches of the surrounding trees. Rough air would collapse the kite completely. Sinking air would suddenly reduce the angle of attack to the point where the kite would death-dive to the grass.
On the other side of the coin, very strong upward gusts would accelerate the kite directly overhead at 100 feet, inflated fit to burst, yanking my arm up with it. In seconds, it would start to float down again like the proverbial bag of washing. Pulling in line quickly, I sometimes managed to re-inflate and get the kite to right itself for another heady climb. At other times, the best I could manage was a timely release of all line tension to reduce the impact!
Enough, enough. Next time we fly this thing, it's down to the beach near sunset. A nice smooth, gentle-to-moderate sea breeze is what this big pale orange Sled Kite was meant for. Then, it might just be possible to get more than 30 meters of line out...
P.S. One good thing came out of this. I did discover a handy technique for flying a strong-pulling kite without a protective glove. I just fed the line through my flying hand, around behind my back, and then out through the other hand to the spare line and winder on the grass. With all that extra friction, it wasn't hard to control the sudden increases in tension.
December 27, 2008 10:59 - A Tale Of 3 Sled Kites
Or, perhaps, MBK Sled-Fest or Sled Kite Triple Treat or any number of other corny titles! As I hinted to my newsletter subscribers yesterday, we went down to Brighton Beach in the late afternoon. The idea was to get all 3 MBK Sled kites in the air at once, one for each family member. Once we got down there, we found space was limited due to the popularity of the beach on Boxing Day, no surprise there. At the time, it just seemed much easier to anchor the kites on the sand, rather than attempt to get 2 3/4 year-old Aren to fly the 1-Skewer Sled on his own!
First up in the steady moderate sea breeze was the Dowel Sled. We were occupying an area on a sand ridge that was perhaps 3 meters (10 feet) high, so the air was a little messed up down-wind of us. After a few collapses and landings, I finally got the big pale orange Sled up into clear air, where it stayed, rock-solid, at a 70 degree line angle. Wow. With about 20 meters (70 feet) of line out, it just sat up there. Poking its nose left and right just a little, every few seconds. The line was like a slim Dacron pole extending upwards from the sand. The winder was simply sand-bagged to the beach with a couple of plastic shopping bags, one inside the other for strength, and half-filled with sand.
Time for sand-castle building with Aren, down near the water line. We were back after only 10 - 15 minutes...
With the Dowel Sled looking very comfortable, I moved cross-wind a few meters and launched the 2-Skewer Sled. Again, a collapse or 2, but soon it was up at a similar height to the other Sled. Two more shopping bags and Aren's toy shovel took care of the anchoring.
Finally, out came the little 1-Skewer Sled! This hadn't flown for quite a while, and in the moderate breeze it had a tendency to loop to the left every now and then. Never-the-less, it managed to stay in the air well enough for us to get a photo of all 3 Sled kites in the air at once! On about 15 meters of line, the little Sled continued to fly while the winder sat on the sand with a few loops of line thrown around a handy small bush. It's hard to see in the photo, but it's there near the top-left.
Having managed to get that photo, it sparked an idea. We will try to get a similar photo for every kite type from now on. Right through to the Dowel Dopero, which will happen round the middle of next year...