Multi-Dowel Kite Posts—Rokkaku

(2-Piece Oak Dowel 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!

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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Multi-Dowel Rokkaku Kite

 

Huge Rokkaku Rises—Only Just

A few sunny days have arrived at last. With light winds forecast, it was an opportunity to loft the big Multi-Dowel Rokkaku to maximum allowable height. Or so I thought.

Down at the reserve the breeze was almost nothing. The 2.4-meter (8-feet) span rok is good in very light winds, but this was going to be a challenge. Sure enough, the outing became a long series of tow ups. Higher and higher they went, as more line was let out each time. But still, the kite just wanted to descend slowly back to the grass.

With a slightly aft center of gravity, the kite would reliably glide backward when given slack in the line. I suppose it was fun doing this for quite extended periods, but really, it was time the thing just stayed up for a while! The 100-pound Dacron line would stretch noticeably as the big rok sat back on its tail when line tension came back on. Often this would be when the tail end was within centimeters of the ground, as I prepared for another long haul up to 200 feet or so.

Finally, in the almost cloudless sky, a large but very weak thermal kept the kite at 60 degrees of line angle for a couple of minutes. Or maybe it was just a period of slightly higher wind speed up there. In any case, it was barely worth it. A sweaty back and sore finger from heavy line rub was the price for finally achieving nearly 350 feet of altitude. It wasn't going to get any better, so, shortly after, it was time to pack up and return home.

Big Roks Make Good Bill-Boards

The big Multi-Dowel Rokkaku has recently been refitted with a heavier lower horizontal spar. Even more recently, I made a large stencil spelling out "my-best-kite.com" and applied it with wide-nibbed permanent markers onto the center portion of the kite. Huge solid-black letters went onto the pale-blue plastic.

Today has been the first opportunity to fly this 2.4 m (8 ft.) span kite since it has a somewhat narrow wind range. But boy does it love light air, going directly overhead at the slightest whiff of a thermal—even weak winter ones, like today.

With an inconsistent and very light breeze wafting across the cracked but grassy surface, it took a few attempts to get the large rokkaku kite up into better air. The more rearwards center of gravity really showed as the kite was very controllable while tailsliding away on a slack line. General stability was also much improved, from previous experience. And this was just as well, too, when the line went slack while the kite was directly overhead at 300 feet! Dives and tight circles always ended in smooth recoveries.

The breeze at ground level was about 5 kph gusting to 7 kph, although an online weather station not far away was recording gusts to 13 kph, higher up. The mid-teens is about it for this kite, even with the beefed-up spar. Attaching the spring scales, the big rokkaku was able to climb slowly on a tension of 3 kg and the heaviest gust popped the reading just over 7 kg.

At modest line angles, this kite is now very steady and predictable, like its smaller Dowel Rokkaku cousin of 1.2 m (4 ft.) span.

Dynamic Soaring With Big Rok

Initially I was hesitant to go out with the light-wind Multi-Dowel Rokkaku kite since winds to the south and north were much too strong for it. Although the local breeze was very light, it all could change so quickly!

My most frequented flying spot was also the most suitable today due to the westerly wind direction. I immediately started the KAP routine that I try to follow each time out with a big kite.

First up, I take a couple of panoramic shots of the locality. That is, three pics that the camera stitches into one—a nice feature! I didn't bother with the wind meter since brief thermal puffs seemed to be all that was happening near the ground.

Next came laying out 30 meters (100 feet) of line and attaching the KAP rig to the line via a half-Picavet arrangement.

Under the shade of a tree, back at the launch point, the huge blue rok quickly took shape. Today would also be its first flight on a shortened and simplified four-leg bridle. Two attachments were on the vertical spar and two on the upper horizontal spar. Hopefully the kite should ride out slightly stronger gusts than it could before.

Then followed many, many short flights. Yep, the breeze was hardly there at all. But it was fun playing around with some delicate dynamic soaring in the wind gradient—when there was any wind at all!

Pull in to tension the line and accelerate upwards. Hang on for a moment to see if the rok will hold height. Pull in again, to a slightly higher height and try again. And so on. Sometimes it was possible to let line out very slowly for a few seconds without losing height, before pulling up even higher.

Another trick was to pull up into slightly faster air, then let the kite float downwind under zero line tension. After a small height loss, another pull in would take advantage of all the extra line length and get the kite much higher than it was before.

Thermal lift was gentle, but the huge rokkaku did make it to about 80 feet once or twice. Still following the KAP routine, I took a few still photos. But that was it. There was no chance of lofting the bamboo cage today!

Sure enough, very shortly after packing away the kite and other gear, a cool breeze sprang up. Looking around, it was no thermal since distant trees in all directions were catching a light-to-moderate breeze. On getting home, the nearest online weather station was reporting gusts to 30 kph!

MD Rok—Line-Working Blisters!

It looks like we might still be waiting for that perfect day to fly the Multi-Dowel Rokkaku, but it looked promising early this morning. A few streaks of mid-level cloud adorned the sky and light breezes were ruffling the foliage from time to time as I looked out the window.

Down at the reserve, there was a light southwesterly blowing. After crossing the dry grass to a suitable point on the opposite boundary, it was surprising how easily the steel pegs went into the earth, to anchor the line reel. Perhaps the tree cover keeps the moisture level higher in the soil around there. 

By the time the big 2.4-meter (8-feet) span rok was ready to launch, the wind seemed to have dropped further. Rather flat cumulus clouds had begun to form, which was not ideal. This rok has a dislike for sudden thermal gusts which stress the lower spar before the kite has a chance to accelerate upwards.

For the next 40 minutes or so I struggled to keep the huge kite in the air. The wood-file work on the stiffer spar pieces seemed to have made an improvement, but a slight turning tendency was still there. Interestingly, it was only at a particular wind speed, plumb in the middle of the kite's wind range. More filing might be required! But it's so worth it when it makes a dowel kite fly straight all the time.

More than once, the rok came right in almost to my hands before another puff of air would tighten up the line and allow a climb. Sometimes this was right up to 60 meters (200 feet) of line. Small birds occasionally marked the regions of rising air as they darted around hunting insects.

Much to my annoyance, a sudden increase in general wind speed plus an almighty gust took out the lower horizontal spar on one side. Down came the rok in moderately tight circles, but I managed to give it a soft landing by throwing out some line at the last second. By now, the entire sky was filling up with brilliant-white cumulus clouds.

After arriving home I discovered a blister on the forefinger of both hands from all that line handling! This kite is not likely to give you line burn in light conditions, but it's still big enough to make you work a bit when handling the line. With just another 3 or 4 kph of average wind speed perhaps, the Multi-Dowel Rokkaku kite would have just stayed up there while anchored to a tree trunk.

More MD Rok Kite Experiences

The aim today was to get out for a good long high-flying session with the big Multi-Dowel Rok kite. Monday and Tuesday were forecast to have 7 kph winds, which was perfect.

However, by this morning, the forecast had been revised to 10 kph for both days. And after getting back just now from the flying field, it would appear the Rok had been battling gusts up to 20 kph and averaging 12 kph! That's right on the limit for the unfortunate soft spot in the lower right horizontal spar dowel. It came close to snapping, I'm sure.

The wind meter had been left at home by accident, so there are no MBK "at the field" readings today. Because of the wind strength and gustiness, flying was a bit uncomfortable which meant no photos or video was taken either.

This kite still needs a little work really. It tends to turn right at times, which could be a curvature mismatch in the upper horizontal spar. This is easily fixed with a bit of wood-file work to make the stiffer spar less so. If that's not the problem, a slight bridle adjustment should help.

Also, a slight increase in the amount of bow in the upper horizontal spar made quite an improvement in the kite's behavior. But I think this would be less necessary if the kite was otherwise spot-on with no turning problem. So no changes are being made to the plans.

This rok also seems a bit reluctant to pull out of a loop/dive situation, requiring some very quick line-loosening to avoid hard contact with the ground. My response? Rather than adding any weight to the tail, I will simply file off a fair amount of wood from the upper 20% or 30% of the hefty vertical spar. Have you heard the old adage "simplicate and add lightness"?

This isn't the most inspiring flight report I guess, but sooner or later some weather will come along that really suits the Multi-Dowel Rokkaku kite. In the meantime, I have a few other kites lying around ;-)

Actually, the kite did spend quite a few minutes flying high on over 60 meters (200 feet) of line, so the outing was not a dead loss by any means.

Slide-n-Climb Kite Launch Technique

It was very warm today, in the early afternoon. A gusty light breeze was blowing in from various directions, although generally from the west-southwest. The big Multi-Dowel Rokkaku has been waiting for some lighter conditions to get a fly, so this was it.

After fixing a curvature problem in the lower piece of the vertical spar I was hoping for a high flight.

Rigging was fairly straightforward, after untangling some of the dowel drums on tether lines that were doing their best to tie everything else up!

Launching was not hard since this big-area kite doesn't need much encouragement to leave the ground. Even so, the messy wind in the lee of the patch of trees near the launch point slowed things down a bit.

This kite really suits the slide-n-climb approach. You let line slip as fast as the kite wants to drift downwind, in a tailslide. As the kite approaches the face-down position, you slow the line, allow the kite to catch the breeze again and then haul it in, nose high. Each time, there is more line out, so the kite climbs higher than the time before. Finally, it's up there in smooth wind and you can just hang on while it goes to a higher angle by itself.

All good fun, this was, but then it got hit by a few patches of rougher air with heavier gusts. And then I noticed the join where the lower horizontal spar had been repaired. It wasn't too long before the constant strains had bent the spar to a crazy angle.

With a 3-leg bridle, the lower end of the kite floats free, so it continued to fly in a balanced way. However, the lower dihedral angle was now extremely generous! It was time to bring it down before the spar failed completely and shredded the sail.

So the flight was cut short, on only 30 meters (100 feet) or so of line. Never mind. This is now a great excuse to ditch the lower 9.5 mm (3/8 in.) spar and replace it with one made from 12.5 mm (1/2 in.) dowel, like the vertical spar. This will have the nice side-effect of shifting the balance point back a little, reducing the tendency to overfly and pitch down at high line angles.

MkIV—Multi-Dowel Rokkaku Refined

Although the wind was very gusty, the strength seemed to be just within limits for the huge rokkaku kite. The next few days will produce some rather windier weather, so it was a case of fly now or wait for quite a while.

I went out with this kite a couple of days ago and came to the conclusion that an upper bow-line was a necessity—at least in these gusty inland conditions!

Perhaps in a location with very smooth winds you could fly again and again with no problems. But the moment the kite goes horizontal, it's in trouble. There is nothing to stop the nose sliding sideways, which soon develops into a dive. Then, you just have to hope the tail swings down in time to effect a recovery!

Today, the winds seemed fairly ideal for the big 2.4 meter (8 feet) span rok, and it easily climbed out to 100 feet or so. Typical of this flying location though, winds aloft were a lot stronger than near the ground. The bowed upper horizontal spars made the kite much more manageable and predictable during lulls in the rough air.

Although the wind meter recorded a maximum gust of only 13.6 kph, some strong thermal activity soon started tugging at the sail and distorting the frame. A fluffy seed pod floated by, also caught up in the rising air.

The kite line was not vertical, so it seemed like there was also a reasonable breeze blowing. Looking around, the treetops had started waving around and producing some leaf noise. Not good! At the same time, the line reel had decided to jam so it was impossible to let some line out to release tension. I immediately started walking out to the kite, bringing it down slowly but steadily.

A couple of minutes later the kite was safely on the ground and quickly de-rigged. After going back to the hose reel which stored the flying line, I found the cause of the jam. The line had looped itself around one of the tent pegs which were holding the reel in place. Maybe it would be a good idea to drive the pegs all the way into the ground, if it's not too hard! 

From what I saw today, the kite is ready to be written up and published as the bonus design in the rokkaku e-book. Perhaps this design isn't the most versatile of the Multi-Dowel Series kites to date, but it should be a real treat to fly in fairly smooth winds with gusts up to about 18 kph. Perhaps it could cope into the mid-20s if you manage to find some harder and stiffer dowel than I used!

MkIV—Multi-Dowel Rok Kite Success!

The earlier versions of the Multi-Dowel Rokkaku kite design didn't seem to be heading in the right direction. Hence I took a bit of a leap (in design terms) and simplified the kite.

So it's back to the tried and true almost-square proportions of the MBK Dowel Rokkaku, for a start. A thicker vertical spar should do away with excessive flexing. Being just under 2.4 meters (8 feet) tall, just one dowel drum was necessary to join the pieces of the vertical spar. This was a nice weight-saving and simplification. The bridle lines were also simplified down to a 5-leg system. To get better angles, three upper and two lower legs were used, all fairly long.

Anyway, this morning proved so calm that I spent about half an hour just thermaling with the Dowel Delta. There wasn't quite enough breeze to keep the huge rok up there, although I did manage to get the upper-most bridle line adjusted.

After taking a few centimeters off the length, the plan worked nicely, with air pressure flexing the upper horizontal spar against the three bridle attachment points. No bow line was required on the upper spar. We'll see how that works out in future flights.

Finally, a slightly more breezy period saw the delta shoot up on 60 meters (200 feet) of line. Quickly bringing it down, I moved on to the Multi-Dowel Rokkaku which had been lying face down on the dry grass.

The wind still turned out to be pretty marginal, but the huge blue rok did get a few slow climbs to around 100 feet off the ground. The flights were aided by my arm and accompanied by applause from a small child and her parents, some distance away :-) 

There were hints of minimal stability, so the bow line on the lower horizontal spar might need to be shortened just a touch.

The kite looked really good up there in the bright sunshine and clouds, with a fairly modest amount of tension in the line, given its sheer size. During lulls, this kite tends to descend quickly due to the longish bridle lines which prevent it going face down very readily. That's a small price to pay for keeping the frame in shape. I'll always prefer shorter bridles for other types of kites though.

The wind meter recorded 5.1 kph gusting to just over 14 kph. This should be a magnificent kite to fly in light-to-gentle winds of say 12 kph gusting to 18 kph!

In Search of the Perfect Rokkaku Kite

Occasionally, a seemingly straightforward design takes a while to perfect. This time around, it seems to be the giant Multi-Dowel Rokkaku kite. Mk I flew beautifully in very light winds—and nothing else! It had a wind range so narrow it would tend to frustrate anyone who tried it.

Mk II was better, with a shorter vertical spar and some changes to the bridle. Also a thicker lower horizontal spar. Nah... it was still too vulnerable to wind gusts. So it was decided to really stiffen up the center section of the vertical spar. And the bottom-most bridle line was dropped, since it wasn't contributing much.

Mk III had a few brief flights today, but the weather had been quite hot and convective. Even around 5 o'clock in the afternoon, vicious gusty periods would storm through, interrupting the almost-calm conditions. Enormous cumulonimbus clouds could be spotted in various directions from the field.

The huge rok managed to hold itself together but was clearly near its limits at times. During this time, with the rok on the ground, I reset the wind meter, then held it above head height for a couple of minutes to see what had happened to the wind. Result: it showed an average 11 kph and gusts to well over 17 kph. Perhaps there was  20 to 25 kph higher up. So much for "almost calm"! 

The current design is probably quite adequate for smoother wind conditions gusting up to around 15 kph. That's all I want out of this rokkaku.

I might try this kite again in better winds. That might be a while, so don't be surprised to see the new Multi-Dowel Box kite take to the skies before then! It exists on paper at this point.

MD Rok MkII—Multi-Leg Bridle Lessons

Winds to 9 kph had been forecast for throughout today. The Multi-Dowel Rokkaku kite has been remade in blue drop-sheet plastic, taking advantage of experience gained from the first Multi-Dowel Rokkaku and also the recently tested Multi-Dowel Barn Door.

It seemed like a hand launch would be impossible today. However, gentle puffs from mid-morning thermals did let me get the huge rok away on a short line.

A problem emerged. The upper horizontal spar was bending far too much in the stronger puffs. Then it dawned on me that the upper bridle line going to the nose of the kite was too tight. This negated the effect of the four bridle legs across the horizontal spar, concentrating stress back toward the centerline of the kite.

Anyway, it just took a few moments to loosen off the upper line by a few centimeters. Back in the air, the kite now flew with a slightly slack upper bridle line to the nose. However, under extra wind speed, it would tighten up.

The outer legs of the upper bridle loops didn't seem to be taking their fair share of load. This was easily fixed by shifting the center loop knots toward the tips a little. Such are the things you can see when flying a big kite up close!

To relieve stress a bit more, the towing point was also shifted forward by a couple of centimeters (1 inch).

In this state, the kite turned in a thoroughly enjoyable very-light-wind flight. Above 50 feet or so, the wind direction shifted further to the east which was handy. There were fewer trees and no power lines in that direction!

Eventually I managed to coax the kite out to 60 meters (200 feet) of line. Soon, it was powered directly overhead in a gentle but wide thermal. At one point I let line slip slowly through my fingers as the 2.4-meter (8-foot) span kite climbed vertically above me. Later, it performed a slow but tight loop up there.

Eventually, the big blue rokkaku started to pull on tension while the nose was pointed downwind. Interesting. But there was no need to panic. By keeping just a little tension in the line, the huge kite obediently flipped around and dropped its tail end back toward the ground, while still at a fairly high line angle.

Meanwhile, the wind meter had recorded an average speed of 2.2 kph, gusting to 6.6 kph, near ground level. 

The Multi-Dowel Rokkaku kite is a very well-behaved light-wind design now, but probably doesn't have a super-wide wind range. That simply doesn't matter if you pick the right time to fly! Future flights should reveal what the upper limit is.

Bridle Mods on the Multi-Dowel Rokkaku

The forecast was promising light winds in the middle of the day, so out we went, with the huge Multi-Dowel Rokkaku Mk1. For a few minutes, I just kept an eye on the wind meter which was peaking at around 20 kph—a bit too much really! However, I decided to chance it, in the hope the extra bridle legs would stiffen up the vertical spar enough.

Rigging the kite took quite a few minutes since the new upper and lower bridle lines needed major adjustment after being attached to the kite. The only way to do this was to let the kite up on just the short bridle line, to eyeball the slack in the new lines. Then I had to get the kite down again and make a first guess at the proper lengths. With the bridle perhaps 80% adjusted, the big rok certainly handled the wind better than before. The vertical spar bent noticeably less than before.

Unfortunately, a 20 kph+ gust came through before I could get the kite down again to fine-tune the bridle lengths. SNAP. There went the lower horizontal spar, quite close to the center.

Not to worry. Seeing the kite all bent up just before the failure gave me a couple of ideas for further minor changes to line lengths and attachment points. Plus of course, the Multi-Dowel Rokkaku MkII is being made in slightly thicker dowel all round.

Meanwhile, work has been progressing on the Multi-Dowel Barn Door. This is designed to fly in stronger winds than the Rok, so nearly every day for weeks has been a Barn Door day—I just need to complete the thing!

Giant Rok Floats Up as Sun Sets

Despite forecasts of steadily increasing wind speeds for some days, the breeze actually dropped right off near sunset today. So I put the newly designed and made 2.4 m (8 ft.) span rokkaku in the car and pulled up at the usual spot. Would there be any wind at all?

Rigging went fairly smoothly, although there is a trick or two to it, due to the sheer size. The first problem—the bridle line connecting the upper and lower bridle loops was too short. Not to be denied an exciting first flight, I just grabbed the upper bridle loop, pulled the two legs together and put a big loop knot into them both at once, at a spot that seemed about right.

It worked. With the flying line Larks Headed around the loop knot, the massive light-wind kite floated up on the very light breeze. So far so good. The big rok headed straight overhead, before settling back down a little.

To sum up, the kite flew successfully but as the breeze freshened to 10 kph gusts, it was clearly too lightly built. At one point, the lower horizontal spars bent severely enough to slacken the bow line enough to let the toggle fall out. The 4-leg upper horizontal spar bridle legs did a great job of holding just a little bow in the upper spar. However, the vertical spar was bending too much, causing the kite to bog down and deform instead of accelerating upwards.

Never mind, I'll make a couple of small changes to this rok, and probably make another with slightly thicker dowel all round. And I'll use "heavy duty" drop-sheet plastic too. The thin stuff is just OK for a 1.2 m Dowel Series kite but not really practical for these Multi-Dowel Series giants! 

It was good seeing the kite sailing steadily in 3 to 4 kph of breeze though, at a nice high angle! After packing up, the wind meter recorded a gust to 9.6 kph, at shoulder level.

 

 

 

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