This instructable is about how to build a simple kitebuggy. It cost me about $100 total, and the only tools I used were a cordless drill and a circ saw. No welding required!
Now, after riding this buggy and looking at some kitebuggy websites, I immediately got lots of ideas of how to make it better. When I got back home, I immediately ordered a cheap mig welder and started filling up notebooks with sketches. Still, this one's pretty good, it'll move at an exhilarating speed, especially if you haven't kitebuggied before, and it's quick to build--probably a few hours once you have everything
woohoo! Kiteboogie on! There are some great kitebuggy pictures of us boogieing that my friend Dick took at http://picasaweb.google.com/ingenious.dick/MirageKiting
*as I'm publishing this one, I'm working on the next version. Let's just say I thought there was too much friction in this one, and I'm playing around with some tarps and gas-powered leafblowers. Tune in in a few weeks and see what happens!
Step 1: Disclaimer
The most glaring flaw with this design is best illustrated by the story of my first attempted ride:
I had wanted to go kitebuggying for a while, so I picked out a dry lakebed in the california desert, called a bunch of friends and told them we were going buggying, let's all meet there at such and such a time. Of course, I didn't have a buggy yet. A couple days before we were supposed to go out, I figured I should remedy my buggylessness, and so a mcmaster order and several trips to the hardware store later, I had a sturdy buggy.
We drove out to El Mirage dry lakebed, an incredibly flat 5 mile x 3 mile lakebed an hour and a half east of LA. I was driving with my friends Jesse and Jessica. We could tell when we were close because we couldn't see anything, since we were suddenly enveloped in a giant dust storm. The forecast had predicted 15 mph winds, but they felt upwards of 25. Pretty exciting. My kite was a Best 2.2m trainer on 75' lines.
For a while, it was pretty exciting. We drove out on the lakebed and met up with my friends Dick, Jenny and Scott. Wierd ATVs and dirtbikes were roaring around somewhere on the lakebed, quite close from the sound of it, but we couldn't see them because the dust storm limited visibility to 10' or so. You could hear ethereal redneck howls drifting on the wind, punctuated by backfires and the smell of exhaust.
When we got out of the car, we were instantly blinded by whipping dust. Fortunately, I had snorkel masks from last weekend's adventure, so we were all soon outfitted in the height of fashion. It was pretty windy, so we amused ourselves by putting up the trainer and getting the bar ripped out of our hands by the wind. Scott got pulled a good 10' before letting go of the kite, and I sprinted about half a mile in zero visibility in the vague direction I thought the kite went, praying that the dirt bike maniacs wouldn't run me over. While I was out running after a kite, some mutant redneck came roaring by our cars in a huge pickup truck, bouncing over 3' bumps and shedding car parts. Things were literally flying off his car, important things like the bumper and some lug nuts from the tires. He didn't seem upset about it, just gunned the engine and roared on out.
After a while, the dust died down a bit, so we put the buggy together. I put the kite up at the edge of the wind, pointed the buggy vaguely downwind and got in. I tried to put the kite into a figure 8 pattern, but it got instantly ripped out of my hands and I had to run after it again.
We were getting tired of the kite getting pulled away, so we decided to make a harness to clip it onto the buggy. We used some tie-downs and rope to make a system similar to the hook-and-loop kitesurfing harnesses use. I put the kite up again, sat down on the buggy and hooked the kite onto the buggy. "A-ha! I thought. Now there's no way I'll lose the kite!" I put the kite into a figure 8. It promptly lifted the buggy and me up into the air and flipped us over. I reached out a hand from the rubble and crashed the kite. I felt glad I was wearing a helmet.
Well, now it was time for reflection and analysis. It seemed that catastrophe struck whenever I put the kite into a figure 8, or more accurately, moved it across the wind with any speed. My solution was to not do that any more. I also felt that there was a certain angle between the kite lines and the buggy's direction of motion that I should not exceed, lest I flip the buggy. This angle seemed to be about 60 degrees on either side. I also didn't like the idea of clipping the kite onto the buggy--it seemed like a bad idea to not be able to depower (drop the kite) in a hurry if I wanted to. Next time: some depower system involving shock cord!
Feeling emboldened by my new revelations, I pointed the buggy downwind. By now, the dust storm had cleared and there was a brilliant blue sky overhead, a steady wind and a gorgeous view of the mountains. All of us had some amount of cuts and bruises from wrestling with the kite. Scott, in particular, had rambo-style cloth bandages on his knees. I'd lost some skin on my fingers from having the bar torn out of my hands. We were all covered in dust.
Anyway, I pointed the buggy downwind, put the kite up at the edge of the wind and sat down. I kind of made little scalloping motions at the wind's edge, just enough to keep 20-30 pounds of tension on the line. The buggy started to roll forward, and the kite instantly started to drop. I steered a bit upwind, keeping the kite in the same spot and the tension picked up, as did my speed. It was then I remembered that Scott was wearing my helmet.
I realized pretty quickly I could control my speed well enough just by putting the kite out of the wind and pointing the buggy upwind to slow down. Speeding up was not a problem. After a while, I grew bolder and tried a tack. I got a nice burst of power as I came across the wind and suddenly I was going 15 mph and bouncing over mounds of dirt and I sped across the desert. I became acutely aware of my lack of helmet. I figured this was as good a time as any to stop, so I let go of the kite, steered upwind and then got out and ran after my kite. Success!
Later on, we all got to buggying around, with a pretty high success rate. At one point, while Scott was making adjustments to the buggy, I was holding the kite and enjoying bringing it across the wind in a high speed dive and letting it pull me ten feet into the air. I grew bolder, jumping with the kite and cutting harder and harder turns. Eventually, I put the kite into a very fast dive, and the resulting line tension had roughly equal components of horizontal and vertical force, resulting in my flying 15 feet into the air and turning a rather surprised somersault before landing on the ground in a heap and then running after the kite, which got loose. Now I'm kinda sore.
Anyway--the buggy shortcomings:
The main one is that the distance from the point the kite is attached(your arms) to the leeward wheel is only half the axle length, or 1.5 feet when the kite is 90 degrees to the buggy's direction of motion. This makes the buggy really easy to flip if the kite generates any pull. I definitely wish I had a wider wheel base.
Fortunately, this is a pretty easy problem to manage--never turn more than 60 degrees off the kite lines, and the buggy is perfectly stable. You don't really want to with this buggy anyway--you won't get any pull in your direction of motion, and you'll be doing a lot of work flying the kite and not getting anything out of it. At my current state of limited knowledge, I'm thinking the best 'point of sail' is for the kite to be 45 degrees from your direction of motion, maximizing both line tension and pull in your direction of motion. If you do find yourself at a higher angle, just don't power up the kite.
Also, some usual kite safety stuff:
Kites are hella powerful. Respect 'em. I'd flown trainers a bunch (50+ hours) and this was by far the strongest wind I'd experienced. I was very glad the kite wasn't any bigger.
It's definitely worth getting acquainted with a trainer before you try the buggy. By 'worth' I mean necessary. It's a lot of things to be thinking about at the same time, and it's good to have some fundamental understandings of all of them.
The general premise of kitebuggying is the same as sailing, so go out and sail a boat around for a bit, and everything on a kite will make more sense.
p.s. isn't this photo awesome? I feel like I should be running around with stillsuits and thumpers.
Step 2: The buggy itself
I'm still pretty new to LA, and I haven't accumulated metalworking tools yet, so most of it would have to be wood.
Also, there were bonus points for making it come apart easily and go on/in my prius.
I eventually settled on a four wheel design with 14 inch wheelbarrow wheels, solid steel axles and a plywood/2x4 frame. The final buggy was about 5' long and 3' wide.
p.s. See those bandages Scott has on? Those are learning bandages. Wear pants, helmets and maybe knee and elbow pads. I'm excited about getting an ugly leather trenchcoat at a thrift store to make my skin un-scrapeable
Step 3: Parts!
As it was, I put in a mcmaster order before I realized how much stuff the hardware store had.
Here's a list of parts I used:
4x 14" wheelbarrow wheels, 3/4" shaft
2x 3' long 3/4" shaft, general purpose carbon steel
8x shaft collars for 3/4" shaft.
4x 3/4" U-bolts with long (3") threaded ends
1x flange for 1" i.d. diameter threaded pipe
1x 1" diameter 2 inch long pipe nipple, threaded at both ends
1x flange for 3/4" i.d. diameter threaded pipe.
1x 3/4" diameter 4 inch long pipe nipple, threaded at both ends
3x 3/4" tee fitting
2x 3/4" diameter 7" long pipe nipple threaded at both ends
1x 3/4" inner diameter galvanized washer.
2x 2'x4' 3/4" plywood
2x 2"x4"x8' two by fours
8x 1" 1/4-20 bolts and nuts
a box of 1 3/4" wood screws
some 1/16" galvanized steel strips
All this came out to ~$100. If you have a decent junkpile you could probably do it for cheaper
Step 4: Building it: The rear axle
Put the wheels, with shaft collars at either side onto one of the axles. Line it up so that the outer shaft collars are flush with the ends of the axle.
Now take a tape measure and measure the distance between the inner shaft collars. Cut a 2x4 piece that length.
Now, on your 2x4, measure in about 6.5" in from either end. This is where you'll put the U-bolts that hold the shaft in place. Mark the spot.
Use the bolts as a reference and making sure they're centered, mark the spots to drill.
Drill out the holes for the U bolts. Go ahead and bolt 'em in place. Now slide the shaft through the two bolts, and go ahead and put the wheels back on, wheel collars and all. When everything's lined up, take a wrench and tighten down the nuts on the U bolts well. Put some threadlocker on 'em, too. My U bolts were too short to clear my 2x4, so I kinda chiseled a hole into the 2x4 a bit to bear the nuts. I actually think this was a good thing, since it let the 2x4 rest flush with the plywood that comprised the cart body.
Sweet! You have a nice secure rear axle!
Step 5: How long are you?
Leave about 6" beyond where you'll put the steering column and then trim off the plywood beyond that point.
If you like, you can taper off the car body--leave a width of 6" or so at the tip for the steering column, but feel free to make whatever shape you want, as long as it'll be comfy to sit on.
woohoo! You have a body!
Step 6: Build the support frame
Find the center of your rear axle(take the wheels off--it'll make the rest of this easier) and line up the 2x4 piece you just cut so it's centered.
Now, take those galvanized strips you got at the hardware store(I don't know what to call these. anyone?)
Bend them by hand into 90 degree angles, and then using woodscrews, screw them into the rear axle 2x4 and the piece you just cut. Do this on either side of the joint.
These galvanized bits won't hold the angle to 90--the plywood will do that when you put it on top, but they will keep the joint from pivoting or flexing downwards much.
Well cool--it's coming right along. All you really need is a front axle and steering
Step 7: Attach the support frame to the car body
Step 8: The front axle
Measure in 6.5" from either end of the plywood strip and mark the holes to put in the U-bolts, the same as you did for the back axle. Also, mark the center of the plywood strip.
Bolt in the U bolts and put the axle through them. Go ahead and tighten down the nuts and put on threadlock. Now, center the 3/4" flange over the center mark you made, and mark location of the four bolt holes. Make sure the holes will clear the shaft on the other side.
Drill out the holes and mount the flange onto the plywood. Use the 1/4-20 bolts and tighten 'em down real good. Put some threadlock on the nuts.
sweet! You've got a front axle.
Step 9: The steering column
(I know my hole is ugly, but it just had to be a clearance hole and I didn't have a jigsaw. I've since bought a jigsaw--I actually just got back from the hardware store)
Now center the 1" flange fitting over the hole you just drilled and mark the four bolt holes. Drill them out and mount the 1" flange onto the cart body.
Screw the 2 inch long 1" nipple onto the flange
Step 10: Putting on the front axle
Screw on the tee fitting onto the 3/4" pipe. Put the 7 inch segments of 3/4" pipe on either end of the tee, and put tees at the ends of those pipe segments. Your steering column is now complete!
Step 11: Ride it around
One thing that's very important to check for is the travel of the front axle. When you steer all the way in one direction, does the axle hit the support frame, or do the wheels run into the cart body? If the wheels run into the cart body, that's no good--they'll bind easily and that's a good way to flip or skid the cart. If that's the case, you'll want to put in stops to prevent that from happening. I screwed some 2x4 blocks underneath the frame to act as my stops.
The last thing you need is a seat. I made mine out of the remaining plywood and 2x4s, but if I had to do it again, I'd do something else.
The important parts are a backrest to brace against and some side railings to keep you from getting pulled out sideways. You can use whatever kind of seat you like. The wood one worked for me, but I wish I'd kept my seat back lower.
Step 12: Outtakes
The first bearing I planned on using was a lazy susan bearing. My assumption was that it was only a thrust(axial) load on between the front axle and the body. I built that version and took it out rolling on the streets near my house. What I didn't realize was that when I push on the steering column to steer, I add a significant radial component, and lazy susan bearings are not built for that. All the balls fell out of my bearing and the steering locked up, making the cart head (to my dismay) down a hill (I live in the mountains, so this is a non-trivial problem). A lot of designs for braking mechanisms went through my head, but I settled on the most practical and grabbed onto the rear wheels as hard as I could. My hands were instantly pulled between the wheel and pavement, where they made excellent brakes. A bit of blood loss later, I was shlepping the cart back home, my lesson painfully learned. The picture was after I washed off--there was a fair amount of blood.
Another thing worth thinking about is that you want to keep your steering column as short as possible. The longer it gets, the more stress it puts in the bearing, and you don't really get any benefit.