Best Rokkaku size for tiny spy camera video?

edited May 2010 in Kites
I'm a total newb on both KAP and kites in general, but would like to get started. While looking for information on Google and in various forums, I ran across this video by Tom Benedict of this forum:

http://www.youtube.com/watch?v=1x5REmV3JX8

The video camera was attached directly to the kite - no Picavet rig - and weighs about 1/2 ounce. I'm familiar with these cameras, although the one I have is the auto keychain remote fob style rather than the gum pack he used. The cameras are $15 or less on Ebay, plus a memory card. In looking at the video, I was surprised at how stable everything was a lot of the time.

Well, I would like to dip my toe into this, but the budget for it is very small at this point. From my research, it appears that a Rokkaku is a good choice for this purpose because it has good lift and is stable (as certainly appears to be the case from the video). But Tom's kite is a 6-ft size, and I've found that I can get a 4-ft Rokkaku for a lot less money, as little as $25 in kit form, plus line. And since we're only talking about a 1/2-ounce camera, with no rig, I just wondered if the 4-ft size might work ok.

I understand (I think) that for a given kite style, larger kites have a better lift-to-weight relationship than small kites, and therefore operate better at lower wind velocities. I was just hoping that a 4-ft Rokkaku would still take off at fairly low wind speeds. At the same time, a smaller kite should tolerate stronger winds, which could come in handy (I'm in Oklahoma). I would appreciate any thoughts anyone might have on this kite size question.

I did look at the possibility of building a larger kite from scratch, but on looking at detailed plans for a 6-ft Rokkaku by Gary Engval, I found that I just couldn't understand the instructions. I don't know the lingo at all, and with no experience at kite building, it all just went completely over my head. Maybe someday someone will do a video. :-)

I think Tom's video is really cool, and would like to be able to do similar videos of all the kids in the family flying the kite. So having the camera always looking back down the line would be just fine for that purpose.

Comments and suggestions would be appreciated.

Wayback
«1

Comments

  • I'm not a small kite expert, but I think you might want to expand your search to small light deltas. They're simpler to set up and I'm guessing (for the same weight fabric and area) will lift in lighter winds.

    And if all else fails trust the wind range on the package at the local hobby store.

    Folks have also used two line sport kites for this. Stability takes skill, but I guess near collisions with trees and the ground would make another type of video.
  • If he's flying the same thing in his video that I've flown on my Cody and a few of my stunters, you can safely fly that on an old plastic Gayla kite :-) I would love to know how his video is so clear though, because I'm pretty sure I'm flying something very similar, if not identical, and the quality is nowhere near that nice.

    I think your primary concern would be finding a kite that has solid reinforcement points so you can attach the camera. He described the video suffering from sail flutter, which I too initially had a big problem with. But by attaching the camera right at the nose reinforcement, that was virtually eliminated [so long as the kite wasn't doing a bunch of stunts].
  • Since I have near-zero experience with this, I based the choice of the Rokkaku on what I found online relative to KAP, and there seems to be a lot of support for using that kite because of its stability and light wind performance. The other design mentioned a lot was the Dopero for very light winds. I did buy a little delta from K-Mart, and tried it out without a camera, but found it to be quite unstable, even with a tail, and it did what I think you call overflying every time the wind picked up - ran straight overhead, then crashed. From what I've read, Rokkakus are much less likely to overfly. I may go for other effects down the road, but I want this one to be stable, and if possible fly staked to the ground.

    fnffishcore:

    Tom's video is described in this thread:

    http://ostro.ced.berkeley.edu/~crisr/discuss/comments.php?DiscussionID=2448

    He has pictures of the camera there, but the Ebay link he gives is long ago expired. If this style is not what you're using, you might want to try one. Apparently there have been improvements in these cameras recently, but they tend to vary in quality quite a bit. So finding a good seller is key. But since these cameras use CMOS sensors, they will all suffer from "rolling shutter" which is that vavy effect you get when things are moving rapidly.

    I think a Rokkaku would provide several ways to mount a gum pack camera, including a fixed mount directly to the vertical rib through a hole in the sail. Tom appears to have taped something to the front of the sail, and then mounted the camera on that.
  • It seems to me WW had fun gorilla taping a camera to different portions of one of his kites. I think a place where the spars cross makes the most sense.

    A lot of KAP'ers use deltas, but a delta is not a delta is not a delta. Do a search on Dan Leigh deltas in general or on this site. Precision built deltas can perform very well.

    Light wind performance has a lot to do with size. You can go smaller but you have to be very specific about sail weight and sparring (i.e. zero wind or indoor kites). Smaller kites generally require more wind and are generally less stable and forgiving unless they are built very well.

    A rokkaku doesn't easily overfly but it will do death dives and 360's if the bridle and tensioners aren't set right or the wind is gusty. There are quite a few threads here on "tuning" the rokkaku and if you get one you should check them out. Tom has a lot of experience setting it up properly and finding good smooth breezes.

    Looking forward to more video :) If you want a leap on this stuff you might want to see if there are any local kapers near you.
  • The rokkaku I used was chosen because I had it in my hand at the time. Yeah, utterly scientific. I did similar tests on a Fled and a couple of other kites. Unfortunately between me and Ben Peoples, we managed to kill that camera and two others like it. Oops!

    I got the 720px version of the camera. They also offer a 640px version of it, so maybe I wound up with a higher resolution camera. I really can't say. I haven't revisited this one in a while.

    Getting back to the kite, yeah, a Gala would carry it with no problems. For at least one of those videos I used blue painter's tape to attach it to the kite sail. I found that wobbled a fair bit. In the end the most stable arrangement was to use a strip of plastic taped to the kite sail with the camera clipped to the plastic strip. This kept the kite sail's fluttering action from making the camera do its rapid nodding action.

    I did build a pretty simple parallelogram pendulum suspension so I could video my BBKK KAP rig in action (it's another action I posted to YouTube, so it's pretty easy to find.) There's so little weight to the camera, the corresponding rig (if you choose to build one) is miniscule.

    In choosing a kite, weight of the camera probably isn't much of a concern. If you can find something that doesn't dance around the sky, you're probably in good shape.

    Cool project!

    Tom
  • "we managed to kill that camera and two others like it" -- spoken like a true hacker :)
  • edited May 2010
    Into the Wind has a bunch of medium-sized deltas that would work well, and as tgran says, they're easier and more forgiving than a rokkaku.
  • Thanks for everyone's comments. But I don't understand why everybody's suggesting a delta. I want the kite to be as stable as possible, and not dance around. From what I've read in the past week, a Rokkaku seemed like a better choice.

    Broox, what do you mean by "easier and more forgiving"?
  • Wayback

    my own experience with trying to use a gumstick camera is that you need a kite that flies more like a plane - that is, it turns gently when the wind alters. The problem with kites like Fleds and Roks is that they respond to wind changes more violently, whereas a Delta (with its keel acting like an inverted tailplane) seems more plane-like. At least that's my guess - at present I don't have a delta but I'm thinking of making a small one just for my gumstick rig.
  • wayback, pretty much any kite that likes to park itself in the sky is fair game for KAP. A lot of us use rokkakus, but a lot of us use deltas, too. If you're reading through the posts and come across kites like the Nighthawk, Trooper RS, Levitation, and Levitation Light, those are all deltas. During World Wide KAP Week last year, ten KAPers used a rokkaku at some point during that week, but eleven used deltas. (See? I KNEW I made that kite index for a reason!)

    There are a couple of reasons why a delta might be a better approach: Deltas have a really simple bridle. There's nothing to tune, nothing to tangle. The "bridle" is the keel of the kite. Attach the line and you're good to go. A rokkaku has a more complicated bridle, with six lengths of line involved at the very least, two points that need to be kept symmetric, and one that needs to be kept very carefully asymmetric. Deltas are easier to set up than a rokkaku, and easier to keep in tune.

    I don't currently have a delta in my kite bag, but I've had my eye on the Trooper RS and the Levitation Light for a while now.

    Tom
  • Tom, I understand that the Rokkaku bridling is complicated, plus the various bowing options, but that just seemed like additional flexibility to make it fly like I want it to, and not necessarily a disadvantage. Also, I've watched some videos of Rokkaku's in actual kite battles, and they just seem remarkably stable in the air.

    It just seemed that since the camera is going to be mounted on the kite itself instead of using a rig, the 4-point bridle would do a better job of keeping things steady than a delta's keel. But if I understand correctly, you're saying that a delta of similar size would have produced just as steady a video for you as the Rokkaku did with the camera mounted on the kite. Is that right? Where would you mount a gumstick camera on a delta?

    Well, weather permitting, I'll try to find the local kite guys this weekend, and see what they're flying and how their kites behave. Unfortunately, the head honcho has already told me that there's no KAP activity in town that he's aware of, so there's nobody to ask about that.

    So how would you feel about the 7-ft Levitation for this? Is that too small? The 9-ft is a lot more expensive.
  • I think it would've been fine on either kite. As far as mounting goes, the camera weighs so little there are lots of options to play with. One of the simplest would be to tape it to the kite sail using painter's tape, and position it near a spar so there's no tendency for the camera to shake from sail flutter. Another option would be to tape a narrow piece of thin plastic onto the top of the sail with the tab poking out past the leading edge. Clip the camera to the plastic, tape in place. (This is similar to what I wound up doing on the Fled.)

    I honestly think any mid-sized kite you pick up would do the job, and then some. To put a sense of scale on this, the 6' rokkaku I used will lift a 1kg KAP rig with room to spare. The gumstick DVR came it at something like 18-20g, or 1/50th of that. It's a 23.75 sq ft kite. I'm oversimplifying here, but knock that down by a factor of 50, and half a square foot of kite stands a good chance of lifting a gumstick DVR camera. I wouldn't fly something that small simply from the standpoint of stability, but even something like a plastic Gayla delta is remarkably steady for its size in conditions that are well within its wind range. Larger kites tend to fly more steadily, simply because they "see" more wind, so small scale turbulence won't affect them as much as it would a smaller kite. Split the difference, and you wind up with something like the 48" rokkaku, the 7' levitation, or any number of other mid-sized kites. If you see a kite described in a catalog as having "good motion", it means it likes to move around. If you see terms like "nailed to the sky", it's probably a good candidate.

    If you're heading out this weekend to watch kites to see how they fly, you might bring your camera and a roll of painter's tape and ask if any of the folks flying kites minded if you piggybacked on their kite and took your camera for a ride. I bet they'd be stoked to see the video footage, and that would give you a better feel for the stability of the kite than anything else.

    Something I'm not sure I mentioned in this thread, or any other thread on the gumstick DVR: Timonoko thoroughly convinced me that video deshaker tools are a good thing when applied to aerial video. (If you haven't seen his KAP/KAV videos from his kayak trips around the Baltic, you're missing out!) I think every video I posted to Youtube that involved the gumstick DVR was run through a deshaker. Something to keep in mind when comparing videos.

    Tom
  • Something I'm not sure I mentioned in this thread, or any other thread on the gumstick DVR: Timonoko thoroughly convinced me that video deshaker tools are a good thing when applied to aerial video. (If you haven't seen his KAP/KAV videos from his kayak trips around the Baltic, you're missing out!) I think every video I posted to Youtube that involved the gumstick DVR was run through a deshaker. Something to keep in mind when comparing videos.
    I was actually wondering if the video of yours posted earlier in the thread was run through a deshaker program... I still can't believe how remarkably steady and clear the picture is! Out of curiosity, I went back to the site where I ordered mine, and I definitely have the 648x480 version. I'm sure the difference in quality has to do with that as well...
  • Thanks very much, Tom. If the weather isn't too bad, I may be able to comapre things for myself this weekend. But I don't have the gumpack camera yet. Just ordered one from the well-known Ebay Hong Kong merchant known as Welcometoauction2003. :-)
  • Sorry for my silence, wayback -- it's been a very busy time for me. But the other guys have said it all. Have fun!
  • Tom, did you build your 6' rok? Or if store-bought, which one is it?

    Here's one that's about 5.5' (actually 65 inches) for $55 plus line. Anyone have experience with it?

    http://www.gombergkites.com/stick.html#rok
  • wayback, I have David's Gomkaku, which is the same size and shape. Flies great!
  • Thanks Broox.

    I'm really leaning toward that 65" "battle" Rok for a number of reasons. They say to use 100-200 lb line. Does that mean I should expect 100# line to work just fine in pretty much any wind the kite will fly in, but 200# could also be used without it being too heavy, or does it mean that 100# only works below 12 mph? The lighter line is less expensive, so I would choose that unless there's a good reason to go heavier. It would be limited to 500' of line, if that matters.

    It's also not clear what size Halo-type winder would be needed.
  • Good strong line isn't overkill -- it's insurance, and worth every penny of "extra" expense. On a rok of that size, use the 200#. Yes, 100# will work, but won't give significantly better performance in light air.

    500 ft of 200# line will fit nicely on an 8" Halo.

    http://www.brooxes.com/
  • I'll toss in one other argument for using the heavier line, if possible: As line strength goes up, so does diameter. Yeah, you get more windage on your line from using a fatter line, but it's WAY easier on your hands, gloves or no gloves. (Use gloves.) Given the choice, I'll use my #200 line every time. Only time I pull out the #150 is when it's clear the weight of the #200 is having an actual effect. And at that point, I've typically given up on KAP and I'm just flying the kite for fun.

    Tom
  • edited May 2010
    I appreciate the advice. I checked out a book from the library by Maxwell Eden - The Magnificent Book of Kites. It's mostly about construction, but has formulas on line strength. Assuming the 65" rok in question is a 5:4:3 design, it would come in at 18.8 sq ft. Eden's formulas would then give from 60 to about 95 lbs at a 25 mph wind speed. But I've found references to these formulas online saying they aren't conservative enough because of possible abrasion or other weakness in the line as it ages, and the losses from knots.

    Ok, so that should take care of the kite, the line and the winder. I've already ordered the gumstick camera and memory card. And I have gloves and a hat.

    Still need to see about a ground stake, and exactly how you tie off to it when using a Halo. I wish there were more how-to videos on all this stuff. I know all this stuff is obvious to you guys, but it's not to beginners.

    What else will I need? Some kind of pulldown gizmo? Anything else?
  • "Still need to see about a ground stake, and exactly how you tie off to it when using a Halo. I wish there were more how-to videos on all this stuff. I know all this stuff is obvious to you guys, but it's not to beginners.

    What else will I need? Some kind of pulldown gizmo? Anything else?"
    I'm not sure if there's a specific name, but I prefer to use (and have seen that others use this in their gear photos) one of those metal, spiral ground screws. I'm not sure if you can purchase them individually, I just happened to have one from a dog lead that we never used. They do take some muscling to get in, especially if the ground is dry. They do work well though; I've used mine to anchor a PowerSled 36 in the sand, and it was rock solid the whole time.

    I also use a sand anchor that my fianc
  • wayback,

    looks like you have not seen the KAP tutorials group Look for my video on tying off to a dog stake and set of photos on walking a kite down. Its a useful resource.

    fnffishcore, you are more likely to see wear on your carabiner which yes will get warm in use. They are designed to act as a heat sink to prevent damage to ropes. Works just the same for kite line.

    Martin
  • We're way off topic, but you should read this thread on walking down, which includes some links to pulleys.
  • edited May 2010
    I'm pretty well settled on a Rokkaku for my first kite, and had focused on one of the 5.5 ft (actually 65 inch) Gombergs for $55. But while doing a final survey of the online shops, I've run across larger roks for about the same money.

    The first is a 6 ft (72 inch) "Hornet" rok for $50 from Colors on the Wind:

    http://www.colors-wind.com/single_kites/rokkaku/rokkaku.htm

    And the second is a 6.5 ft (78 inch) rok "Extreme" for $58 from PicturePrettyKites:

    http://www.pictureprettykites.com/single-line-kites/rokkaku-kites/rokkaku-extreme/prod_249.html

    Since the initial use for this kite will be KAV using a gumpack camera mounted on the kite, lifting capability isn't the issue at this point, but might be later on. But stability definitely is an issue, along with tolerance of a wide range of Oklahoma winds. I guess my instinct is to go for the largest kite, but I'm not sure that's the right answer.

    I don't know the exact measurements of these kites, but if they are 5:4:3 roks, then we would have:

    Height / Square Feet
    -------------------------
    65" / 18.8
    72" / 23.0
    78" / 27.0

    So that's a pretty big difference in area. Another issue is that while the Gombergs seem to have a good reputation, I really don't know anything at all about the others from the quality standpoint. They say the 78" Extreme is made by New Tech Kites, but I can't find any roks on New Tech's website.

    Well, I don't expect there's a definitive answer on this, but if anyone knows anything about these other kites or sellers, that would be helpful. I kinda feel that the 78" might be too big for me when the wind picks up. But going up to the true 6 ft kite might well be worth doing at essentially the same price, if the kite's any good.

    Thanks for any thoughts or suggestions.
  • edited May 2010
    The 78 inch premier is probably one of the most popular roks on this forum. You can see a little discussion on the 78 inch versus smaller GomKaku here:

    http://ostro.ced.berkeley.edu/~crisr/discuss/comments.php?DiscussionID=2121

    I have an older New Tech delta which is well balanced and built. But the spreader had to be switched out after a little experience with it (in order to make the wind range a little better). For the premier rokkaku a lot of this experimenting has already been done and you'll find recommendations for new spars in the forum. Might apply to the 78 inch you list above.

    David
  • Should I be feeling lucky?

    I ordered a kite this morning, and a couple hours later they call me. They say since this is the last one of this model they have in stock, and since it isn't made anymore, they checked it carefully to make sure all the spars are there, etc. And during that process they found a 1/2 inch slit in the sail - somewhere near the middle. Don't know exactly what that means. They assured me the kite had not been sent out and returned, but had no explanation for how the slit occurred

    So they are gonna repair the slit with some kind of repair tape, check the kite again, and call me back. Oh, and they're gonna knock $20 off the price.

    I have no experience with this kind of thing. Is the repair likely to provide a long-term fix, or should I steer clear of this one? This would be a 78" Rok, made several years ago by New Tech, for a net $38 plus shipping. So if the repair is likely to work, it might be a particularly good deal.
  • Buy it. Sounds just fine to me. A small slit like that will make no difference whatsoever, except perhaps cosmetically.
  • Well, the 78" New Tech "Rokkaku Extreme" finally arrived. The store included what looks like rip stop repair tape, either white or clear (not sure yet), and I think the repair should be fairly straightforward. But I'd appreciate some guidance on a few things.

    The horizontal spars are one-piece, but the vertical is two sections connected by a 4" long aluminum ferrule. The slit in the sail is right at one end of where the ferrule will go. Of course that may be coincidence, but the end of the ferrule was actually pretty sharp. So I got out a small file and carefully rounded off the end edges of the ferrule, just in case, then painted over that with black enamel. I hope that reduces the chance that the edge of the ferrule could cut through the sail, and hopefully won't compromise anything.

    The reason I was able to easily do that is because the ferrule just slides off. It isn't glued to either section, and I don't understand what would keep it from just sliding down the lower section in flight and breaking the connection. Surely it's supposed to be taped or glued to one of the sections. Right? Is SuperGlue/CrazyGlue ok? The spars are supposed to be fiberglass, if that matters.

    The vertical spar goes against the sail, then the horizontal spars behind it - right?

    Well this is a pretty cool looking kite. I started out looking at a 4' Rok, and ended up with a 6.5' with 2.5 times the sail area. Talking with the local kite guys, my impression that we had lots of high wind here (Tulsa) really isn't correct. As one of them said, "Only if you're a golfer." And they said I'd just get a lot more use out of a larger kite that works in low-to-moderate winds. So we'll see how this works out.
  • I"d guess that the slit came about because the ferrule slid down, exposing the sharp edge of a spar.

    You're right, the ferrule should be attached to one section or the other. I've had better luck with 5 min epoxy than superglue, but usually wrap a couple inches of black plastic tape around it just to be sure the ferrule doesn't slide.

    IMO, it doesn't matter which side of the spine the spreaders are, as long as they're secured snugly at the crossings with a tie or twist-tie or O-ring.
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