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Archive for the ‘Kite’ Category

Recording Kite Line Scream

Posted by Tom Benedict on 28/09/2015

Anyone who’s flown a kite and held the line to their ear knows the sound of wind screaming over a kite line. The big plastic hoop winders many kiters use for larger kites are perfect for this. Just barely touch the line to the side of the winder, and the whole thing acts like a loudspeaker. But how to go about recording it?

A couple of weeks ago I built a contact microphone using tips from Zach Poff’s page. The mic consists of a piezo disk, a 6′ length of Mogami microphone cable, an Alex Rice piezo preamp, and an XLR connector. I salvaged the connector from a cable in the to-go pile at work. (Neutrik connectors are still on order.) The cable is the same stuff I’ve been using for my EM172 mics. I ordered the preamp boards from OSH Park, and the components (the list of which can be found on Zach Poff’s page) from Mouser. I got some piezo disks from Mouser as well, but I wound up using one I’d salvaged from a piezo buzzer ages ago.

The only trick when building one of these is that shielding is important. No, let me put that another way: Shielding is IMPORTANT! The first time I tested it, I picked up horrendous 60Hz buzz. I fixed it by insulating the preamp and the piezo disk, then covering each one with copper tape, which I connected to the shield in the cable. Once it was shielded from the XLR to the piezo disk the buzzing went away.

I’d describe all the rigorous tests I performed on it, but mostly I just played. I recorded sound from the supply and return lines on a CTI cryocooler, the sound of a PCC cooler (which is totally different), and the sound of pasta sauce simmering by attaching the contact mic to the end of a spatula and sinking the other end in the sauce. It worked great!

So today I took it out with me while I was doing KAP (and KAV and KAS).

Not much to the setup: Tascam DR-70D, headphones, contact mic, and blue sticky stuff. And a kite and line, of course. (And my hat to cushion everything, ’cause those rocks are like razors!)

Contact Mic Recording

I tried attaching the mic to the line two ways. The first was to stick it on the line itself using Blu Tak (the sticky stuff you get for sticking posters to walls.) This worked great, but braided Dacron likes to stick to the sticky stuff a little too well. When I removed the mic, I was left with gooey bits I had to pick off the line.

Contact Mic on Line

So for my second attempt I stuck it to the carabiner on my ground anchor strap. This worked as well. The mass of the carabiner helped damp some of the higher frequency sounds, leaving more of the bass notes. Unfortunately it also picked up the twisting/creaking/grinding sound of the ground strap.

Contact Mic on Carabiner

I think suspending a carabiner midway along the line would provide the best of both worlds: more bass notes, but better isolation from the ground strap. Unfortunately I didn’t try this. I also didn’t try just sticking the contact mic directly to the winder! Things to do next time.

Still not happy with how Soundcloud embeds in WordPress documents, but in case you’ve never heard kite line scream, here ya go!

Attached to the kite line:

Attached to the carabiner:

Both are mono recordings. (Hey, now I need to do this on a two-line sport kite so I can record in stereo!

On a whim I took a look at the spectrogram of the recording with the mic stuck directly to the kite line.

Line Scream Spectrum

Talk about harmonics! The primary is somewhere between 500Hz and 1kHz depending on the line tension, and the 2x, 3x, and 4x harmonics show up quite strongly.

Fun stuff…

(Told you I wasn’t testing this with any kind of rigor!)

– Tom

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Posted in Audio, Kite | Leave a Comment »

KAS – aka In Over My Head (again)

Posted by Tom Benedict on 15/06/2015

Some years ago I was hot on the idea of launching a high altitude balloon, festooned with cameras I’d used for doing kite aerial photography. I still have some of the bits and pieces from the balloon payload I never built, including a really neat little styrofoam cooler a co-worker was throwing out. In the process I watched a ton of videos from high altitude balloons (HABs), but none of them struck me like one I found from a launch in Florida. Unfortunately I haven’t been able to find this video again, or I’d share it here. What set it apart from the others was the lack of a music sound track. Instead, it used the audio from the camera. What I heard blew me away.

The balloon was launched from a city park. In the video you can hear all the normal sounds of a park: kids playing, dogs barking, the launch team talking amongst themselves. Just after launch you continue to hear these things, but gradually they die out, to be replaced by sounds of nearby traffic. Eventually the traffic dies out, leaving only a siren wailing in the distance. Finally the only sound left is that of an airplane flying well below the balloon, which at that point is over 50,000′ above the ground. After that, nothing.

I never did build a HAB of my own, but that video made me fall in love with the idea of recording sound from the air. I tried using the microphones on my KAP cameras, but the on-camera audio, even on a camera like a Canon T2i, is pretty poor. The microphones are tiny, the sound is hissy, there’ s no wind protection, and the T2i has automatic gain control you can’t turn off. (Later models like the T5i have this as a menu setting. Good move, Canon!) A few years later when I got into doing video on the ground with my T2i, I got a separate audio recorder for just this reason. It didn’t take long before I flew the recorder on a kite, but the sound still wasn’t great. No fault of the recorder, mind you. It worked perfectly. But I could hear the rig servos, the Picavet pulleys, line sing, and everything else going on on the KAP rig. I gave it up as a bad idea until I could think about it more.

So I thought about it. And I researched it. And I started learning the intricacies of field recording. I hit on Paul Virostek’s blog and bought a copy of his first book, “Field Recording: From Research to Wrap”. If you’re interested in sound and field recording, I highly recommend Paul’s book. He doesn’t start with the assumption that you have to own the latest, greatest, most expensive equipment. He starts with the assumption that you want to record sound. It’s a good place to start.

I haven’t had a lot of time to pursue my hobbies recently. I spent the last nine days painting and re-flooring my house, and in all that time I picked up a camera only once: to photograph the new floor. But Saturday morning I found myself in Kailua-Kona with time on my hands before my next appointment. “Aha!” I thought, “I’ll go record the surf at the Old Airport Park!” I grabbed my field recording gear and headed that way.

What followed was a comedy of errors worthy of a Marx Brothers movie. I set up to record surf, only to hear a persistent helicopter sound. I looked up to see a whole slew of skydivers with US Army canopies, and a Chinook flying overhead. The skydivers were landing in the park. One of the points Paul makes over and over in his book is that field recordists need to approach things in terms of serendipity rather than ruined opportunity. I couldn’t record the surf because of the helicopter, but I could record a helicopter!

I ran over to the landing area in time to catch it. But the mics on my little field recorder were overwhelmed. By the time I’d dumped the gain enough not to clip, the helicopter had landed and the event was over. I stuck around for takeoff, only to find I’d accidentally paused the recording until the helicopter was out of range.

So I went back to the surf, only to find the skydivers had jumped again, and the Chinook was coming back down. Back to the landing field!

This time I got a better recording of the helicopter, but the crowd noise was a little overwhelming and I still clipped. I got a good recording of the takeoff, though. Back to the surf!

I finally got a good surf sequence, but at the tail end a large set of waves came in and swamped my location. I grabbed my gear before it got splashed, only to have my windjammer fall off the end of my recorder and into the water. It looked like a little floating hairball. I fished it out, rinsed it off, and called it a day of lessons learned. Two days later it’s still damp. One more lesson learned: don’t let these things get wet!

I’m still a fair way from being ready to try kite aerial sound again, but I’m getting closer. I know what went wrong with my earlier sessions. I  know I want to wire in the audio channel on my video transmitter and set up my ground unit with a headphone jack. I also want to test all my gear in a studio box to see if I’m picking up RF hum from the transmitter. I now have real motivation to change from Picavet to pendulum suspension for the rig. I know I need line dampers to take out line sing, even though the KAP community moved away from them years ago. The list is long.

After that it’s a question of building a KAS rig that’ll give me the aerial sound I want. Right now I’m looking at building a variation of Curt Olson’s Olson Wing using EM-172 capsules, which I found from Zach Poff’s article. I’ve got other supplies from an earlier attempt to build windjammers for a borrowed pair of lavalier mics that should let me cut down the wind noise as well. I’m still not sure what I’ll use all this for, but it should be fun.

– Tom

 

 

 

Posted in Audio, Engineering, Kite, Kite Aerial Photography | 2 Comments »

Reasons I Left the AKA

Posted by Tom Benedict on 23/02/2014

A couple of years ago I let my membership with the American Kitefliers Association lapse. A bunch of stuff was going on at the time: Rydra was getting a craniotomy to remove a brain tumor. I’d just been assigned the task of designing and building the mechanics of two CCD cameras for a new instrument. And artistically I was in the dumps when it came to kite aerial photography. When the renewal notice came in the mail, I didn’t even open it.

I originally joined so I could take part in the annual AKA KAP photo competition. The competition takes place at the AKA Annual Conference, an event I’ve never been able to afford to travel to. The rules are simple: Print up to three photos made using a camera suspended from a kite, and mail them to the AKA rep by the due date so they can be presented at the convention for review. Conference attendees vote on the photos, and the winner is declared on the last day of the convention. Only members in good standing with the AKA can compete. When I let my membership lapse, I let my ability to enter the competition lapse as well.

I had opportunities to rejoin the AKA. Rydra recovered from the brain tumor. I finished the two cameras for the new instrument. And I eventually got back into kite aerial photography and photography in general. The Annual Convention came, the competition was announced, and still I didn’t renew. Maybe next year. Or maybe not. I just didn’t feel a need to rejoin.

When I was a member of the AKA I got Kiting magazine. The format for Kiting typically includes a cover story – usually a convention – contributed articles – usually about conventions or competitions – and the reports from the Regional Directors – usually covering conventions and competitions. Oh! And one KAP article. Except for the KAP article, I really didn’t get a lot out of it. My Regional Director never once mentioned the state I live in, never once covered an event out here, and his report never really had much in it that applied to me. Increasingly, I got the feeling that if I wasn’t on the competition or convention circuit, I wasn’t really doing kites. Not the way the AKA expected me to, anyway.

I also got on the AKA’s online forums. Just like Kiting magazine, these mostly focused on competitions, conventions, and why the AKA has such a hard time attracting and keeping members. I tried to contribute to the forums, but I never got the feeling my input was ever really read. Apparently my version of kiting just didn’t apply. Over time I quit logging in. There wasn’t really anything there for me.

About a year ago I got into RC airplanes. Gliders, specifically. No, they didn’t take the place of kites for me. In a way I learned to appreciate kites even more for how cleanly they use the wind and the air. And I joined the Academy of Model Aeronautics – the AMA. So when my shiny new AMA membership card arrived in the mail, I was eager to see what the AMA’s approach was like.

For starters the publication I got, Park Pilot, covered a lot more ground than Kiting. Articles covered choosing a radio, choosing a plane, new gear reviews, how-to construction articles, tips on flying aerobatics, tips on approaches and landings, how to put together a crash kit for the field, and how to fly safely. There were even articles about competitions, but they were never the entire focus of the magazine. As a beginner, and even after a year, I felt represented.

Over time I gravitated toward sailplanes. I was a little alarmed to find out that it’s an incredibly competitive branch of model aeronautics. Speed records are set by high-end carbon composite dynamic slope soarers. Precision soaring events are won by carbon kevlar bagged wing ships flown to within a second on a clock. Timed pylon events are run using only the lift generated on slopes. I’m not a competitive guy. I fly to have fun. The AKA’s focus on competition was one of the things that drove me off. The deeper I dug into sailplanes, the less I thought there could be a place there for a guy like me.

To my delight I found that there was. RC Soaring Digest, a volunteer-published magazine for RC soaring enthusiasts, covers these competitions, but unlike Kiting it also covers construction techniques, walks around full-sized sailplanes, travel articles showcasing wonderful places to see and fly, historical articles on record attempts, even articles covering people like me who just want to put a plane up and have a good time. It’s all fair game.

Eventually I joined the RCGroups forum. Though not an official part of the AMA, the RCGroups forum is, nonetheless, the online watering hole for all things RC. There are forums there to discuss competitions and rules. But there are also forums to discuss scale modeling, DIY electronics, radios and radio mods, foam planes, home-built planes, slope planes, thermal planes, jets, helicopters, multirotors, seaplanes, you name it. If it can be flown, it’s represented. If it can be stuck in something that flies, it’s represented. And when someone like me gets on and posts a wacky idea, people read it and comment on it. Sometimes they even get excited about it.

Between the KAP Forum, the AMA, RCGroups, and RC Soaring Digest, I had my interests covered. I was disappointed the AKA wasn’t part of it, but such is life.

Some months back there was a proposed rule change for the annual AKA KAP competition. I weighed in as a KAPer, and non-KAP members of the AKA weighed in as well. The discussion was very slanted. One non-KAP participant implied that KAPers were basically greedy bastards for not donating their prints to the AKA convention auction at the end of the competition. Another questioned that sending prints to the competition could cost upwards of a hundred dollars or more, arguing that a Walgreens print only costs $25 to print and ship. (Walgreens?! Do they use Hahnemule paper and archival inks?) When KAPers pointed out that maybe… just maybe… someone who has put thousands of dollars and hours into their art might not be satisfied with a drugstore print, the non-KAPers basically blew them off. End result? No changes to the rules. Don’t like ’em? Don’t play.

So I didn’t.

Today I got email from the AKA saying how regrettable it was that I hadn’t renewed my membership, and asking me to participate in a survey so they could better serve the kiting public. So I participated. The questions were good. Why did I leave? Why didn’t I renew? What did the AKA offer that I most valued? What would it take to get me back? I answered as truthfully as I could.

Reading back through my answers to the questions, I was a little surprised at how acerbic I was. But the more I thought about it, the less I wanted to change what I wrote. Because in the end it was the truth. This is why I didn’t renew. This is why I don’t plan to come back. And this is what it will take to attract kiters like me. Want to attract new members? Learn to bend.

– Tom

Posted in Kite, Kite Aerial Photography, Photography | Leave a Comment »

A Progression of Kites

Posted by Tom Benedict on 13/11/2013

In my previous post I gave a bit of a history of the cameras and gear I use for KAP. But I left out the most important part of KAP: the magic levitation machine that makes the whole thing go. The kite.

Something I didn’t know when I first got into KAP is that while any kite can lift a camera, you don’t use just any kite to do KAP. When I ordered that first Brooxes BBKK kit years ago I thought I had a good lifter kite. It was big. It had pull. Perfect, right?

As it turned out, no. It was a big parafoil with the most amazingly complicated bridle I’d ever seen. I never could quite get it in tune. The kite did fly. I can attest to that. But if the wind dipped even slightly or gusted, it would quit flying. And sometimes it would overreact to a wind shift and just take off sideways. It was fine when all I was doing was flying it as a kite. But for KAP it was frustrating!

Turns out the kite had an amazingly narrow wind range. Wind range is the term used to describe the wind speeds a kite can operate in. There are a couple of reasons why you want kites with wide wind ranges when doing KAP.

First, the wider the wind range on your kite, the fewer kites you need to cover a range of speeds. Say you have a bunch of kites that can handle maybe 4mph difference in wind speed. To cover everything from 5mph to 25mph, you need five kites. You could cover that same range with three kites that have a broader wind range.

Second, hanging weight on a kite line effectively shrinks the usable wind range of the kite. At the high end the kite will still fly off the wind and crash. But at the low end the kite will simply run out of lift, and your camera and rig will hit the ground. So if you start with kites that have a broad wind range to begin with, chances are it’ll keep flying when you hang a rig on the line.

Finally, nearly every flying session will involve a range of wind speeds. It’s inevitable. We don’t live in a wind tunnel. Real wind has dips, gusts, thermals, down-drafts, etc. Real life is messy. If you start with a kite that can deal with a range of wind conditions, your chances of keeping your camera in the air when the wind changes goes up.

I wound up selling that parafoil and getting a pair of related kites: Flow Forms.

ff16

The Flow Form is a soft kite invented by Steve Sutton. In many respects they look a lot like my earlier parafoil, except for the bridle. The Sutton Flow Form bridle is a very simple arrangement of lines that don’t need to be tuned. The tuning is all in the keel geometry. The Flow Form 16, shown here, starts flying around 6-7 knots, can lift by 8-9 knots, and only starts to over-power around 20 knots. For me it was a great place to start doing KAP. It packs down to a bundle the size of a travel pillow, and can be pulled out, shaken open, and launched with relatively little effort. It’s still my go-to kite for travel.

Unfortunately Air Affairs, the company that made the Flow Form 16 and Flow Form 8 I bought, are no longer making the kites. The KAP community is still trying to find good replacements. So far some of the better ones come from HQ Kites. But I’m still trying to keep mine patched and flying.

For the record, I don’t use my Flow Form 8 for KAP any more. It’s small, and smaller kites are more prone to react to small changes in air pressure. Put another way: they dance in the sky. This is not what you want as a stable platform for photography. By the time the wind is fast enough to let me fly a rig from the FF8, I’m ready to pack it in. At those speeds the wind is abusive.

Unfortunately, with just the FF16 in my kite quiver, there were days when the wind was too light to fly. So I started looking for other kites. This is where your local flying conditions and your own preferences for KAP will drive which kites you gravitate toward. In my case I needed lighter wind kites, so that’s the direction I went.

Larger Flow Forms were available, but I wound up going with framed kites. Soft kites are good for getting “reach” (downwind range) without incurring too much altitude. For getting out over water, or for flying over difficult to reach subjects they’re great. But for getting lots of altitude when you have to stand close to your subject they’re not ideal. For that, framed kites are a better choice.

My first framed kite was a 6′ rokkaku a friend of mine sewed using the plans from Gary Engvall.

Hexagonal Levitation Machine

A well-tuned rokkaku provides a great deal of lift in a little amount of wind, and is a joy to fly. A poorly-tuned rokkaku is a disaster on the end of a string. I can vouch for Gary’s plans, my friend’s prowess with a sewing machine, and above all Gary’s bridle tuning guide found on that same web page. This kite continues to be one of my favorites. It’s 6′ high and 5′ wide, and breaks down to 5′ if I leave the cross spars in place. It’ll break down to 32″ if I break down the spars.

I later added a second rokkaku to the bunch, a 7.5′ from Didakites. The bridle it came with was awful, but after I replaced it with as bridle made to Gary’s specifications, it became a solid flyer. Because of the sensitivity to bridle tuning I don’t recommend rokkakus as first kites. But they make great second (and third!) kites.

About that same time I also made a new winder out of half inch plywood, a bunch of bolts, and a skateboard wheel. It’s shown here with my Didakites rokkaku.

The winder

It flies in lighter wind than the 6′ rokkaku, and is now my main kite for lifting my DSLR rig. (Remember how heavier rigs will reduce the wind range of whatever kite you’re using? It also helps to start with a kite that can lift more weight.) This one is 7.5′ high and 6′ wide, and only breaks down to 6′ unless I break down the cross spars. So it’s a little less convenient to carry, but it’s fun to use.

In an ever-expanding quest to fly in less and less wind I picked up two other kites along the way. The first was a Fled, a kite specifically designed for KAP by Brooks Leffler.

Fled

It’s almost the same size as my green rokkaku, but flies in much less wind. It’s also not capable of carrying as much weight. Like the Flow Form it has a bridle that doesn’t require tuning, so it’s a good beginner kite. But it’s only really suited for lifting the lightest rigs. I’d never fly my DSLR on this. But I’ve flown compact cameras, cell phones, and Gopros, and it’s one of my go-to kites for mapping. (Mapping KAP rigs only let the camera point down, and tend to be very light and easy to use.) It breaks down to the same size as my green rokkaku unless the vertical spars are disassembled as well.

The other is a DoPeRo, another kite also specifically designed for KAP by Ralf Beutnagel:

Dopero

DoPeRo is short for Double Pearson Roller. If you imagine the above kite without the rectangular center panels, that’s what a Pearson Roller looks like. Throw in those panels and it’ll haul up even heavy DSLR rigs in almost no wind. The one catch with the DoPeRo is that it’s 6′ high and 9′ wide. It’s big. In my case it’s too big and too complicated to be assembled without putting it on the ground.

Here’s another instance where your local flying conditions will dictate some of your choices. A great deal of the KAP I’ve done has been over raw lava. If you’ve never stepped on rock that’s less than a hundred years old, imagine standing on a pile of broken glass. Early on I learned how to hold a kite in the air while installing all of its spars, and then launch it without letting it touch the ground. I can’t do that with the DoPeRo, so I can only use it at sites that are ground contact friendly.

I love flying the DoPeRo, and try to get it out every time I go to the beach. But it’s not my primary KAP kite because of the whole issue with the razor sharp rocks. DARN! If you do the bulk of your KAP from grass fields, though, keep the DoPeRo in mind. It’s a good performer. Like the rokkaku, it’s sensitive to tuning. In this case Ralf’s original plans are the go-to for problem solving.

One whole branch of the kiting world I haven’t mentioned is deltas. There are some incredibly affordable delta kites that make beautiful lifters. The Levitation Delta and its sister kite, the Levitation Light, both from Into the Wind, are excellent lifters for under $100 US. Unfortunately I don’t own either one so I can’t tell you of my first-hand experiences. But I’ve seen both flown, and can attest to their utility for KAP.

A delta I have flown is the PFK Nighthawk. As far as I know these are only available from Paul’s Fishing Kites in New Zealand. These are some of the craziest kites I’ve ever flown. They start flying around 6-7 knots and can lift upwards of 10-12 knots. I don’t know the top end of the wind range on the Nighthawk. A fellow KAPer has flown a Nighthawk off of a boat in gale force winds, and managed to do KAP of the boat. It is an insane kite. I find that it pumps the line when it’s up in a lot of wind, though, so if your KAP rig is prone to oscillating it may not be your best bet. Either that or add a bungee between the kite and the rig. (Yes, this works. But that’s another post…) When every other kite is hiding in your kite bag, the Nighthawk can still come out and play.

One last delta I have used for KAP was a 19′ delta I borrowed for an archaeological KAP session.

Big Delta

This thing is terrifying to fly. I’d only use it for KAP if I was absolutely desperate. I have a standing offer to buy one of these from a kite shop that closed its doors a while back. I might get it simply for lifting line laundry at kite festivals. But only if I flew it off an anchor, and only if I was using #500 line or stronger. Even in light wind it’ll go from slack line flying to iron bar arm-wrenching pull in seconds. It’s a monster.

There are lots of kites out there that are good for KAP. The KAP Forums are a great place to ask questions and get feedback on any kites you might be interested in getting. The folks there are some of the finest in all the Internet. Kites, cameras, rigs, radios, no matter what your question is, that’s the first place I go.

Something to keep in mind if you get into KAP is that conditions won’t always lend themselves to flying a camera. In those instances you can always just fly the kite to fly the kite, and enjoy the scenery for its own sake.

Evening Landing

And should you accumulate a whole quiver of kites for doing KAP, they can all get air time when the wind is wrong, the light is bad, or you just don’t have a subject that turns you on. It’s all fun.

Three Birds on a Wire

Besides, once you get into kites it’ll give you a whole new perspective on the world. We all live under the same sky. We all fly in the same wind. And when someone tells us to get lost, we all get to go outside and play.

Go Fly A Kite Poster

– Tom

Posted in Kite, Kite Aerial Photography | 7 Comments »

All Kite No KAP

Posted by Tom Benedict on 03/06/2013

One of Rydra’s friends from high school was on the Big Island, so we set up a get-together at Hapuna Beach over the weekend. The wind was good, and I had all my KAP gear with me, including my new video ground station. It really was perfect for doing aerial photography.

But I’ve done so much KAP at Hapuna, I just couldn’t bring myself to hang a camera from the line.

A year ago I might’ve panicked at the thought, but honestly, I took it as a good sign. In the last two years, a combination of not wanting to be too far from Rydra and an overall shuffling of personal priorities have meant that almost all my KAP has been done at Hapuna. At various times I’ve been afraid that I’ve lost interest in KAP. But I finally realized the root of the problem wasn’t the KAP, it was the flying location. I’m tired of doing KAP at Hapuna!

So with a smile on my face, I pulled out a kite and my winder. Not to do KAP, but just to fly.

The PFK Nighthawk launched smoothly and easily, and flew so well, I decided to pull it in and swap it out for the Flow Form 16. That flew so well, I put the Nighthawk on a 10′ tether and attached it to the line, too. When those two were flying well, I added my green 6′ rokkaku to the line and put all three up. This is the same stack I did back in January. It was fun then, it was just as fun now.

Eventually the wind started to drop, so I pulled those three kites down. The kids wanted to fly them, so I stuck each one on a short tether and handed them off to the kids while I put up my Didakites rokkaku. Eventually the wind dropped enough that the Flow Form wouldn’t stay inflated, so I packed it away and handed my Fled off to my daughter. (If you’ve lost count, I’m up to five kites.)

Toward evening, the crowd began to disperse enough to consider flying a sport kite. I tied my rokkaku off to my kite bag, pulled out Rydra’s and my Widow, and laid out the lines on an open stretch of beach. I got twenty glorious minutes of flying before a group of people walked straight into the area I was flying and dropped their stuff on the sand. I was a little disappointed, but I wasn’t going to risk their safety. I landed the Widow, packed it up, and headed back to our spot on the beach.

The wind continued to die down as the sun began to set, and one by one the kids handed me the kites they’d been flying so I could pack them away. Eventually even the rokkaku didn’t want to stay in the air, so I pulled it down, too. As I was packing it away I realized there was only one kite left in the bag that hadn’t flown: my Dopero. The wind was light, but there was still enough of it to fly!

It only flew for about ten minutes before the wind failed altogether, but I was grinning ear-to-ear as I packed it away. One beach, one afternoon, seven kites. At that point I couldn’t care less that I didn’t get my KAP stuff out of the bag. This is what it’s all about – good company, good wind, a bag full of kites, and no limits. I was in heaven.

This is the difference between KAP and most other forms of aerial photography. The end-all be-all with KAP isn’t getting the shot at all cost. Some days the gear doesn’t even come out of the bag. And sometimes those can be the best days of all.

– Tom

Posted in Kite, Kite Aerial Photography | 2 Comments »

Kite Monopole

Posted by Tom Benedict on 06/05/2013

World Wide KAP Week 2013 is over, and despite having to work all week and a bad run of weather, I got out more than I thought I would. I’m not planning to write much about the individual sessions because by and large they were KAP sessions like any other. But I got to play with some stuff that’s worth mentioning, so over the next few weeks I’ll write about them.

The first is the kite monopole.

All this started when my 808 #16D camera arrived. I got it after seeing some stuff that John Wells had done with his, including converting one to do near-infrared photography. My initial thought was to fly it on an RC airplane, positioned so that the airplane played a major role in the video rather than just being the aerial platform the camera was attached to. By taping it to the tail, I was able to see all of the control surfaces on the wing, while watching the plane fly. Too cool!

Having seen that, I knew I had to try it with a kite. So on a whim I decided to put a tripod on top of a kite and tape the camera onto that. The resulting video was an instant recipe for motion sickness! But it proved the idea could work. I just had some stability issues to work out.

I knew that I wanted to try it again during World Wide KAP Week, this time doing stills instead of video. I wound up using a Gopro Hero3 rather than the 808 #16D (which really is a video camera, first and foremost). And this time instead of building a tripod, I made a guy-wired monopod using a replacement spar from Rydra’s and my Widow sport kite. The idea was that this would allow the kite to flex more than the tripod had, and would transmit less of the kite’s motion to the camera. I think it helped, but what really made the difference was that I switched from a Nighthawk (a pretty jumpy high-wind kite) to a large rokkaku (a much steadier flier that can’t handle as much wind).

Gopro Monopod - Setup

Setup was a pain. There’s no other way to put it. Tying and tensioning the three lines to hold the monopod at the right angle was a drag. I arranged most of it at home, including tying the two prusik sliders for the rear legs of the guys. Unfortunately by the time I got to the beach all the knots had slipped, making it a disaster of strings and knots, none of which wanted to slide. But eventually I got everything sorted and let fly.

Gopro Monopod - Let Fly

Then the second problem hit: Without multiple legs, there was nothing constraining the camera to point forward. The monopod rotated around its axis and flopped off to one side. I flew long enough to take about 30 pictures, saw what was happening, and landed it.

Gopro Monopod - Fixing Things

Making modifications to this setup in the field was complicated by my far-sightedness. There is no way to look suave while wearing reading glasses over your sun glasses. Not that I worry overmuch about that kind of thing, but people did get a kick out of watching me tweak this thing. I wound up re-tying the guy wires so they led to the camera rather than to the monopod. This put more of a righting moment on the whole rig, and kept it pointing forward. After that, it was time to fly.

Gopro Monopod - In Flight 1

In the end, it worked! It gave me exactly the view I was after: one that showed the kite in the air as a kite, similar to the video I made using the RC airplane. The idea behind the two was the same: show the aircraft doing its thing, rather than hiding it away. We sometimes get so wrapped up with the idea of using a kite and camera to make beautiful pictures that we forget the kite itself and the way it’s being used are beautiful as well.

– Tom

Posted in Kite, Kite Aerial Photography | 1 Comment »

I Knew It! – Where RC Airplanes are Leading Me

Posted by Tom Benedict on 13/02/2013

I’m starting to see a pattern…

When I was a kid, I loved kites. The idea that something that had no power source of its own could fly was fascinating. It was even more fascinating to tie payloads to my kite string and lift them as well. (Those little green baskets that strawberries used to come in were awesome for making gondolas!) I should have known it was a sign of things to come.

Years later I got into sailing. I’d been on power boats, but they just didn’t do it for me. Again, I think the fascination had to come from the idea of being in a vessel that had no inherent power source, but that still moved through the water with ease. No surprise, my wife and I gravitated toward catamarans – some of the most efficient sailing vessels ever made.

When I got into aerial photography, I guess it was only natural that I returned to kites, albeit seriously upgraded from the ones I used as a kid. Using kites for aerial photography offers serious operational benefits, such as the ability to sit in one location for hours, if necessary, until the light happens. But it has non-photographic benefits as well that go back to why I got into kites and sailing in the first place: the silence, the power, the peace.

And now I’m getting into RC airplanes. For a variety of reasons the plane I chose has a large high-aspect wing, low wing loading, and a decent glide slope. These are all features you want when sticking camera gear on an airplane. But they benefit something else as well: using the plane as a glider. And the more I fly it, the less inclined I am to use it for aerial photography. It’s just too fun to fly! And the more I fly it, the more I find myself cutting the motor entirely and gliding. Just like flying a kite, flying a glider is therapeutic.

The problem has been finding places and times when I can fly. The wind around my house ranges from moderate to torrential. But it’s almost never zero. When I got my plane I thought that kites and airplanes would fill two different parts of the wind regime: zero wind = airplanes, moderate wind = kites. Too much wind means the plane stays home. And there’s almost always too much wind. I thought I was stuck. But all that changed when I discovered slope soaring.

When wind encounters a slope, hill, cliff, or even a generously sized building, the wind has to go up and over the obstruction. This creates an upward moving body of air just in front of and above the slope. Put an airplane in that body of air, and it flies. And since energy is being pumped in in the form of upward moving wind, the airplane can theoretically fly indefinitely, just like a kite. This works so well, the airplane doesn’t really need a motor at all. All it needs is enough oomph to be able to use the lift from the wind and turn it into speed.

There are, of course, idealized regimes of airplane design that lend themselves to slope soaring better than others, just as there are idealized regimes of automotive design that lend themselves to racing on flat pavement better than others. But any car will roll if you position it at the top of a hill and release the brake. Likewise, practically any RC airplane can be used for slope soaring. It may just require a slightly different setup than what you’d normally use for open field flight.

It turns out the Bixler 2, my first and so far only RC airplane, makes a darned good slope soarer. I discovered this when I couldn’t find a good place to fly. I finally wound up at the cliffs above Hapuna Beach where a moderate on-shore wind was blowing. The cliffs make a decent slope, and the almost completely laminar on-shore wind make for wonderful flying conditions. I wound up flying for more than half an hour, and only had to use my motor a couple of times to correct my rookie mistakes. When I put the battery on the charger afterward, I was amazed to see it top off with only 330mAh of charge. It’s a 2200mAh battery. I could’ve gone for hours.

When I got my plane, I felt a little dirty – like I’d stuck a motor on a sailboat or put a propeller on a kite. I should’ve known it wouldn’t work out like that. Instead, I found a way to make the airplane fit right along with everything else. It doesn’t matter if it’s kites, boats, or airplanes. It’s all about the wind. It’s always about the wind.

– Tom

Posted in Kite, RC Airplanes, Sailing | Leave a Comment »

Silly Kite Fun

Posted by Tom Benedict on 01/02/2013

I haven’t written much recently because work has been kicking my ass. In the last month our dome has stuck open, we’ve had a cracked water pipe that resulted in a full-building flood, we had multiple electrical fires because of flooding in the breaker boxes, and we had all the associated clean-up you’d expect from a month like this: total network failure, failed cryo systems, failed vacuums on every instrument in the facility, and one heckuva mop job to get all 1200 gallons of water out of the building. It’s been a nightmare. What’s a guy to do?

Fly kites, of course!

One of the weekends (I think the one before the flooding began) I was at the beach with my family with a pretty minimal KAP setup and only three kites. The light wasn’t great, but I put up a kite anyway. Sometimes it’s nice just to put a kite in the air and hang onto the string.

But it’s also nice to complicate things needlessly, all in the name of fun! I had a short leader in my bag, so I tied it onto the line and tied on a second kite. And when those two flew nicely, I had to put a third on the line just because I could. Then I thought it would be a good idea to relax a little more and fly all three kites with my foot.

Three Birds on a Wire

This isn’t the first time I’ve flown a kite with my foot. I think the first one was during World-Wide KAP Week 2009. But it’s been a habit ever since. My wife never ceases to be amused and confused at me for doing this. After a few minutes she said, “Why not fly a camera, too?” So I did!

Three Birds The Moon and A Camera

So there I am in the middle of building-wide failures at work, flying three kites and one camera at the beach with a silly grin all over my face. Little did I know I’d be fighting fires the next day. Literally.

– Tom

Posted in Kite | 3 Comments »

Branching Out – The Bixler 2

Posted by Tom Benedict on 27/11/2012

I’ve been doing aerial photography from a kite for over five years now. I started in 2007, using a borrowed camera and a kite that was never designed to lift things. These days I’m flying a DSLR and have a quiver full of kites, all of which were chosen specifically for KAP. I’ve come a long way, and still have a long way to go. It’s as much fun to pursue now as it was when I lifted my first camera off the ground. But there’s more in the air than kites.

When I was a kid growing up in Houston, a guy lived down the street from us who worked at NASA. He was brilliant. He was also a lot of fun. He and a bunch of his friends flew RC airplanes. This was back in the day when every plane was made from balsa, and the big players in the radio market were companies like Kraft. Everything ran on gas, and a “small” plane had a wingspan wider than I was tall. To say I was envious was an understatement. But even then I knew it was way outside my budget and skill level. I got a real thrill from watching him fly. But I didn’t think I’d ever be the one doing the flying.

As with KAP, things have come a long way with RC airplanes, too. It used to take skill and patience to turn a box of balsa wood into an airplane, and crashes used to be heart-stopping affairs that often spelled the destruction of months of hard work. These days you can pick up a ready-to-fly or almost ready-to-fly plane made out of foam that can be glued back together after a crash, and be flying again within the hour. Engines used to cost more than two years of allowance. These days a complete brushless DC power system might cost a quarter of that. Servos and radios used to be big bulky affairs that cost more than my body parts were worth on the black market. These days a complete Tx/Rx and servo set cost less than the plane they go in. In short, RC airplanes have finally become affordable for guys like me. So I asked for one for Christmas.

I don’t think it’ll take the place of KAP. For starters most of the KAP work I do relies on the camera being stationary in the air. I can do aerial panoramas if the camera is sitting still. Just spin it in place and trip the shutter. If the camera is on a moving platform like an airplane, that’s a lot harder to do. I also enjoy flying kites too much to ever stop now. Even when conditions aren’t right for photography, I’ll often put a kite in the air just so I can hold the string and smile at the wind. And really that’s what I want to get into RC airplanes for: to have fun. Because if watching my neighbor all those years ago is any indicator, they’re a LOT of fun.

But that’s not to say I’ll never stick a camera in a plane. Cameras, too, have come a long way since I was a kid. These days you can stick a tiny brick of a camera in an airplane and get a high quality video of the flight. Thousands of people are populating their airplanes with first-person view cameras and video downlink systems, GoPro nose cameras, tiny gumstick cameras stuck out on the wing tips or on the landing gear, etc. At some point curiosity will get the better of me and I’ll give it a try. So I wanted my first plane to give me enough room to grow.

All of which made for a fairly broad set of requirements for the plane. I wanted it to be a good beginner’s plane. I wanted it to be cheap and easy to fix. And I wanted it to have enough capacity to let me eventually cram a camera into its guts. I wound up asking for the Bixler 2 from Hobby King. It’s a 1.5m wingspan motor glider that was designed with FPV and cameras in mind. An excellent video from Flite Test discusses the origins of the Bixler 2, and the similarities and differences between it and its predecessor, the Bixler. The biggies are that the Bixler is smaller and faster, but harder on its battery. The Bixler 2 has a wider wingspan and a slower motor driving a larger prop, which leads to its longer battery life. The Bixler 2 also incorporates flaps, though you have to supply your own servos to use that option. (Yes, I asked for the flap servos as well.) The whole thing is molded from EPO foam, so repairs are fairly straightforward.

Now for the kicker: The Bixler 2, flap servos, ESC, three LiPo batteries, a LiPo charger, and an RC glider backpack all cost less than my G-Kites Dopero. (This helped sell the idea with she who actually orders my presents.) So much for RC airplanes being out of my price range. All I need now is a donor camera to stick in it. (Did I really say that?) No, seriously… First I have to learn to fly.

– Tom

Posted in Kite, Kite Aerial Photography, RC Airplanes | 4 Comments »

Scary, Smart, Loud ‘n Clear – My Weekend

Posted by Tom Benedict on 20/08/2012

Sorry, no good machining stories or photography stories from the weekend. I did start drawing up the main halyard winch from our Pacific Catamaran in the hopes of building a new one, but it also looks like I can press the old one back into service with a little work. And I brought my KAP gear to the beach on Sunday, but didn’t put a camera up. Still, the weekend wasn’t without story material:

Scary

Saturday morning, we decided to pick up all the toys in the yard, clean up the porch, basically de-redneck. (No, my Jeep is not up on blocks yet, but that’s another story from the weekend.) My son grabbed all the slippers and crocs from the back porch and took them inside to clean. Why he brought them inside to clean in the bathtub instead of using the hose outside, I’ll never know. But he did. And somehow I wound up having to clean the tub, not him. (Go figure…)

About halfway through, the screaming started. Loud screaming. Screaming with purpose! That could mean only one of two things. I tore off running for the bathroom. “What happened?!” I yelled.

I saw a brown widow spider!” my son replied.

I took two things away from this: One, there was a brown widow in my bathroom – my son knows full well what they look like. Second, he saw it, but wasn’t bit by it. WHEW!

In case you’re not familiar with brown widows, they’re quite similar to black widows. Their bite packs only a slightly less mighty wallop than the bite of a black widow. For a kid his size, it would’ve meant an ER visit at the very least. And yeah, the place where we live is rife with them. Normally when we encounter a stray animal in the house, we stick it in a container and take it somewhere safe for the animal to be released. But I draw the line on centipedes and brown widows. My younger daughter teared up when I flushed it, but down it went. I breathed a sigh of relief. So did my son.

Smart

Some months back the left side mirror on my Jeep fell off. The pivot had rusted through, and it just flopped off on the ground one day. There was no way to put it back together, so I ordered a new pair of mirrors off an online Jeep parts retailer. The new mirrors came in a few days, and… there were no instructions. I looked through my repair manual. No help there, either.

From what I could see, they screwed in from the inside of the door. ??! The inside? How the heck was I supposed to do that? I looked at the door, but didn’t see any real way to get at the screws. So I tossed the mirrors in the back of my Jeep and learned to drive with two out of three mirrors. For the record, no, this isn’t safe. And no, it’s not smart. And actually, I’m pretty sure I could’ve been pulled over for it. But my options were starting to look like removing the door panels, taking out the windows, and then drilling through the inside of the door since there was no other way to get at the screw heads. I figured I could wait on it until my next safety inspection.

Which, of course, came due in August. Oh wait! It’s August! And just in time, my car blew a turn signal bulb, lost most of its brake fluid, and came due for an oil change. It really does hate me. I swear it does. But I love it anyway. So Rydra and I drove to NAPA and picked up stuff for an oil change, air filter change, a new set of bulbs, and brake fluid. When we got home she said, “You need to replace that mirror if you want to pass inspection.”

“Yeah, I have them right here.” I showed her where they’d been living in my car for the last few months.

“Why haven’t you put them on?” she asked.

I went into the whole song and dance about how I’d have to take my doors apart, maybe drill into them, etc. I sounded like a total whiner, I’m sure. She stared at me through all of this, then proceeded to show me how the covers snap on and off of the things so you can get at the screw heads really easily, because they’re on the outside of the door where a sensible person would put them. What I had been struggling with for months, she figured out in under ten seconds. >sigh<

(Now do you see why I get frustrated when we can’t find any women applying for our telescope engineer positions!)

She graciously helped me install my new mirrors, and stood by while I topped off the brake fluid. “Why was your fluid low?” she asked.

“I don’t know,” I replied.

As she walked inside she said, “I’d look for a leak if I was you.”

I looked under the car. Brake fluid was oozing out of my left rear brake. >sigh< One more repair on the list: rebuilding the rear brakes.

Loud ‘n Clear

After the whole “let’s work on the Jeep!” fiasco, we headed down to the beach. I love going there. It helps that Hapuna Beach, one of the top ten rated beaches in the world, is less than fifteen minutes from our house. I also just never run out of stuff to do there. From swimming to boogie boarding to diving off the rocks, it’s a great place to go. Of course half the time I do none of those things because I’m doing something else. Reading a book, flying a kite, doing kite aerial photography, it’s all fair game.

Hapuna A650 July, 2011

This time I brought my KAP gear, but I brought something else as well: a shortwave radio. I’ve had one for ten years or so. But ever since getting my ham license, it’s been something of a tease. “Here! You can listen, but you can’t taaaaalk! Hahahaha!” Yeah, whatever. But until I have my General license and an HF rig to use, it’s as close to the longer bands as I’m going to get. Like the song goes, it’s not having what you want, it’s wanting what you’ve got. So rather than stress it, I’ve been having fun with it.

But a radio is nothing without an antenna. And often it’s the antenna that makes the real difference, not the radio. So some months back I started looking into what I could do to improve the reach of my shortwave. The idea is pretty simple: Run three wires in parallel, each of a different length, and connect them all at one end. Make the lengths right, and you have a multi-band antenna. I got the idea from this site. (Yes, yes, the site calls for four wires. I only had three-conductor wire on hand, so I lost one of the bands. It’s still pretty darned cool!) But rather than hang this from a tree or a post, as in the article, I suspended it from a kite line. A ground wire running down into the wet sand let me use the beach and ocean as my ground plane.

The antenna went together in an afternoon, and was easily rolled onto an old kite line spool I had lying around. And that’s where it sat for a long, long time. We had stopped going to the beach for a while, so I didn’t have reason to pull it out. This time, I was pulling it out!

The antenna weighed less than my DSLR KAP rig, so I knew the kite would lift it. Once it was airborne, I clipped the antenna on and let line out to hoist it up. Every ten feet or so I had another clip so the kite line would support the antenna for its full length. When the entire antenna was up, I tied off the kite line and set the ground spike in the sand. Then I plugged the antenna into my radio and turned it on.

HOLY COW!

I had no idea the radio waves were that jammed. I picked up China easily, then picked up several Australian stations. Next was a whole set from South America (though my Spanish is too poor to figure out which ones). Next was Japan. These were all incredibly clear. It didn’t even qualify as DX the signal strength was so high. I thought I heard one that was either German or Dutch, but I couldn’t be sure. Just to make sure the antenna was actually doing something, I unplugged it. (It’s a receiver, so no chance of a blown output amplifier stage.) Dead silence. I plugged it back in, and WHAM! Everything was back.

We had to leave well before I was done scanning all the bands my antenna gave me. I didn’t even take notes on which stations I’d picked up. There were just too many. I’ll be more systematic next time. I swear.

When I got home, I did some poking around just to see what it would take to do this with an HF transceiver. As it turns out, not much. Since this was a receive-only antenna, I got away with using very lightweight wire. But MFJ makes a multi-band center-fed dipole that looks like it would hang from a kite line, too. The antenna is rated for 1500W of transmitter power. I doubt I could find an HF rig that would fit in a backpack that could even come close to that. So the antenna problem is solved.

Just more incentive to hit the books and get my General license. Meanwhile, I’ve got something new to do at the beach on the weekends.

– Tom

Posted in Engineering, Hawaii, Kite, Kite Aerial Photography, Radio | 5 Comments »