Public Lab Research note


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The Squid and the Rok

by cfastie |

I might have missed Squid Week, but I had to wait for the rain to stop. The squid kite is part of Public Lab's current Kickstarter and some people have been trying it out this week for kite aerial photography (KAP). I was gifted a squid kite at the last LEAFFEST and tried it out in October, but it was too windy that day to fly a camera with any of my kites so I have been looking forward to trying Squidward again.

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Above: Squidward dances as he swims in the sky and winks at you.

Squidward is a fun and highly expressive kite. It is a parafoil kite with tubes that fill with wind and give the kite an aerodynamic wing-like shape. Most KAPers use kites with spars because they generally provide more lift, fly at a higher angle, and perform much better in low winds, but parafoils work well to lift cameras when there is enough wind. Without stiff spars, parafoil kites can't keep their shape as well as sparred kites and tend to wander more. So parafoils are almost always flown with long tails to produce drag which helps keep the kite pointing into the wind. This drag reduces the lifting power and causes the kite to fly at a lower angle. The first several times I flew a camera I used a Sutton Flowform 16 parafoil kite, but I haven't flown it for the past few years.

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Above: To correct Squidward's lean, I attached a carabiner to the left lower bridle attachment. One was not enough, but three carabiners had an effect and Squidward stopped leaning to the right so much.

Squidward tended to lean to the right (my right) and would eventually start a dive to the right which was hard to stop. This must be because of asymmetry in either the sail or the bridle. I couldn't tell which it was, but as a quick fix I added some weight on the left side of the kite to compensate. One carabiner was not enough, but three (10 grams) seemed to reduce the lean and prevent dives.

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Above: Adding about 10 grams to the lower left side of the kite reduced the rightward lean. Taking some binder clips in the field might be a better way to make this type of adjustment.

My goal was to fly the lightest PowerShot rig I had. I used a PowerShot SD1100 on a stripped down Aerobee Rig. The camera had no protection, but it was an old camera and I was flying in a lush hay field where landings could be lenient. The JerkPan on the Aerobee was engaged, so I was able to pan the camera by jerking the kite line. The entire rig weighed 200 grams.

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Above: When Squidward was flying well I attached an Aerobee Rig with a PowerShot SD1100. The Aerobee was stripped of its legs and camera tray to save weight. The Aerobee Rig frame has 1/4" holes which allow a camera to be attached without the tray.

Squidward could lift the rig, but not very high or for very long. There was about a 10mph wind which is plenty for lifting cameras with most of my kites, but Squidward needed a little more.

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Above: The Aerobee Rig never got very high, but it captured a few nice photos of the Bread Loaf Campus.

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Above: Is this the first aerial selfie taken by a squid kite? Is it a squelfie?

Instead of adding weight to the kite to compensate for its lean, it would be nice to adjust the bridle. But the bridle has 18 lines so that is a tricky adjustment to make and probably should not be attempted in the field. There might be other modifications which could improve the flight characteristics. Most parafoil kites have vents which let some air out of the wind-inflated tubes. Maybe cutting some strategic holes in the tubes would help.

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Above: A Sutton Flowform kite with four tubes. Each tube has an open hole through the fabric.

The squid kite can be purchased inexpensively from China. I am curious about whether the kite makers there could make a delta kite almost as cheaply as the squid kite. A delta requires less sewing and typically has no bridle and no tails. It would have to be a little bigger and would require four spars. Even at three times the price of the squid kite, a delta might be a better tool to put in the hands of beginning aerial mappers.

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Above: A homemade Rokkaku kite lifting an Aerobee Rig with PowerShot S100. This rig weighed 386 grams, almost twice the weight of the SD1100 rig.

To provide a baseline for my observations of Squidward, I also flew another kite which I had never used to lift a camera. My friend Ellie is an experienced seamstress and agreed to try her first kite after I provided her with lots of ripstop, Dacron, and Velcro. She made a seven foot tall Rokkaku which is the most professionally made kite I have ever seen. I built the spars from P200 and P400 wrapped carbon fiber tubes and the tangerine Rok flies beautifully. I had flown it twice before but the wind was not right for KAP then.

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Above: The Aerobee Rig lifted by the Rok had the JerkPan engaged and took lots of photos in different pan directions. This panorama is stitched from 19 portrait mode photos taken by the S100. The view covers about 200 degrees.

The Rok experienced some of the same wandering that characterized the flight of Squidward, so it is good to know to attribute that to the wind. In a 10 to12 mph wind the Rok is at the upper limit of its range, so it was pulling really hard and could have lifted much more than the 386 gram Aerobee S100 rig. I'm sure the 900 gram Saturn V Rig I flew with the SkyPod recently would have been lifted without issue.

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Above: Julia wishing her little friends a good flight.

The Bread Loaf School of English is in session, and a masters student came to see if her very small friends could take a ride. Julia is taking a class in children's literature and was looking for inspiration for her assignment. We strapped the adventurers onto the line and let out a few hundred feet of line under the Rokkaku. I'm looking forward to reading the account of this endangerment from the perspective of the flight crew.

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kite-mapping vermont kite-aerial-photography kickstarter kap mini-kite-kit squidweek squid aerobee-rig rokkaku

3 Comments

Great advice on the "tilting" fix -- this affected one of Liz's squids and we struggled to adjust the bridle, eventually giving up.

I posted this with a link under the Kickstarter FAQ!

https://www.kickstarter.com/projects/publiclab/kickstarter-gold-balloon-mapping-kits/faqs#project-faqs


Can we get a better look at that gorgeous Rokaku?! Is it hard to travel with?


I have been meaning to do a post about the Tangerine Rokkaku. I have yet to have a full KAP session with it so I hope that will happen soon. Here is some footage of it on its first flight three months ago.

I was really impressed that even in a stiff wind there was so little fluttering. That is one of the reasons it pulls so hard -- the wind's energy is not wasted flapping the kite sail around. Parafoil kites can be designed to be very quiet in the wind, but the squid kite is designed mostly to look really awesome. Hence my comment about looking for a simple delta for new mappers. Just the maintenance and launching difference between no bridle and an 18 line bridle is a strong argument, and there are others.

I made all the spars in three sections, so the sections are a little longer than two feet. So it is no harder to pack than my other sparred kites. Anyway, the priority should be lifting cameras, not travelling.


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