The one-hour shelters have done their job: all the Tinkerers slept in their creations without mishap. The excitement of the Juniors’ camp-out was not repeated (no earwig infestation and no sliding or rolling out of the tents).

Hanna helps Robyn with packing while she waits for Pearls’ welded gear cluster. She’s going to give the drill cart one more try. She has the patience of a saint.

Platinum has experienced a new form of failure, which no amount of welding will be able to repair. The drill chuck has completely separated from the drill. Time to remove all that dead weight for some gravity racing.

Some early morning welding has got the Slackers cart running again. The team takes turns roaming the parking lot (giving the other Tinkerers a go at it as well).

With their newly welded gear for the lower drill, and a hand-me-down gear (from Platinum) for the upper drill, Pearls just needs the chain installed. Hanna notes that today there is less hopelessness bubbling out (of the tire).

For a while there was some real doubt as to whether the Slackers could get powered, but it’s been done. The throttle seems to be controlling only one drill, but it’s enough.

At long last Hanna is rewarded with an actual ride across the parking lot on Pearls. Fully powered. Both drills, working perfectly, providing torque galore. Until….

Pearls throws the chain, for no apparent reason. With the derailleur-style tightener, the tension on the chain is substantial. Careful analysis shows that rather than jumping off the precision-aligned gears, the gear is stepping down through the chain rings. But why? It appears that the torque is so massive and the attachment of the drill is now so secure, that the plywood mount is flexing. Note that the lower (visible, since the cart is overturned) drill is mounted on a single small piece of plywood. Not even the 3/4″ ply – it had been determined to be unnecessary….

Twyen is not fazed by the irreparable failure of Pearls – he is test-driving all the other carts on the lot. While the power of Slackers is satisfying, it just can’t compare with the downhill speed of Platinum.

Now that Pearls has proven powerful (albeit flawed), Hanna does a downhill race against Isaac. But Pearls just wasn’t designed for speed, and torque and maneuverability aren’t needed for gravity racing.

In front of our favorite barn, we present the Tinkering School Class of 2009 (Seniors), along with the collaborators, experts, and documentarians.

A new timeline for pick-up results in everyone – including all the parents, siblings, and a few friends – getting a tour of the barn and projects at the same time. We’ll have to do this every year; it’s fun to show everything off at once.

Toby describes to his dad how the Slackers cart works.

Slackers (as the only reliable power system), is set up to demonstrate. And magically both drills get triggered by the throttle! The crowd roars.

Gever gathers everyone to say thanks, and Jiro points out that the week was a complete success – no fingers were lost! The parents are pleased, but Maxine thought she HAD lost a finger, and has to check to confirm that Jiro is correct.

Gever is happy to give a mini-tour of the animals, including a refresh of the mud pit and a little bonus bathing.

Chun isn’t so shy when he’s behind the wheel (or bars, but “behind bars” might give the wrong impression :-), and looks pretty happy. Theo is definitely happy, now that he’s shown Chun how the brake works and it hasn’t been held down during the entire push up the hill this time.

You don’t think that Theo intentionally sabotaged his helmet-cam so we’d ask him to redo his downhill run to get the first-person footage, do you? He certainly is happy to oblige, even with a camera duct-taped to his shirt and neck. After this he gets to help take everything apart and relocate Tinkering School back to Gever’s workshop. As do I. Thanks for following along!

Experience the fast-paced world of gravity cart racing, with Pearls.

Slackers chugs its way around, carrying all who want a ride.

At long last, Pearls muscles its way across the parking lot, under full power.

Theo rides one more time, for the cameras.

Maxine and Amy head out.

Elkus Ranch has the added bonus of various cute animals and lovely gardens. Even the weeds are beautiful.

With fresh eyes we hope to tackle the remaining glitches in the various systems and do some real powered cart racing today. Theo and Isaac try to solidify the persistent falling-off-chain problem.

Today we get our official introduction to the animals. Gever really likes the goats.

Toby and Leo work on fenders for the Slackers cart, since it’s almost ready to race. Most of the clamps are in use, so Toby supplies the anchor for the material. He also seems to be supplying some remote tool guidance.

Pearls continues to struggle with gear problems. The shaft has bent and the washer/nut installation is slipping. So everything gets welded together. Which later proves to be quite out of true (since the washers had warped so significantly). We have no extra gear clusters.

Maxine can’t believe that the throttles will require yet another tweak to get working. After rerouting (to better center) the cable, they find that the drill has too much give and shifts whenever pressure is applied. More mounting restraints are added.

Platinum is working most reliably, although the load on the drills to go uphill (even just slightly) pulls them out of position and throws the chain. The bungie system has give, and it turns out a static solution is required. But they can’t find a large enough clamp to test the fix, so double-clamp two quick-clamps together. Really?

Now that Platinum seems to hold its chain reliably, Emma takes her for a spin. Uphill (slightly) or downhill they keep on motoring.

The throttle connections are unorthodox, but once the pull fulcrum is centered it does the trick. Note that this is before the additional drill restraints are added.

It turns out that the Ranch Director’s Jack Russell loves to play soccer. And proves to be quite good, intercepting the ball and even doing a tackle – much to the chagrin of the experienced players.

Leo has heard the cart is ready to test, so dons his favorite helmet. Maxine wants to finish installing the fenders, since then they are Done. Leo is too anxious for that, and insists on waiting in ready-position.

The cart can’t handle the torque with the weight of a driver. This is where it’s determined that the drills need additional restraints.

Virtually every human on the property has been consulted on the problem with Pearls. Gever doesn’t believe the problem could be insoluble, but he just hasn’t quite figured out what to do next.

Not only does Pearls have a persistent gear problem, but now the tires are leaking some sort of milky liquid, that oozes from several places. It makes a disconcerting sort of wheezy sound, especially when you’re working close by.

Slackers (aka SLKRS) are fully outfitted now, with fenders and matching interior.

Toby has found the giant lens Gever has salvaged from an old overhead projector. He’s found a nice thick piece of wood to burn his name on to. It’s surprisingly easy to write with.

Everyone really wants Pearls to be able to race, but figuring out how to make that happen is slow-going. Burn-writing and sledding are encouraged to keep the gang occupied.

The off-axis gear cluster is unusable, but luckily Platinum can easily have the chain removed to provide a loaner. With the loaner in place and the top (well, bottom since the cart is turned over) drill mounting reinforced yet again (thanks to Bryan’s awesome wood+metal drilling+screwing), Pearls is ready to race.

Note the addition of a drink holder. The team successfully restrained themselves from riding until something broke.

With a chariot-style ride, the low-slung vehicle actually seems the tallest when ridden.

Luxury foam footrests and coordinating duct-tape accents make Pearls truly fashion-forward.

Gever takes the drivers through the figure-eight track. No one seems to be too concerned about the up-hill start, although it’s so subtle many of us didn’t really notice it.

Everyone lobbies to have Pearls race first – we all want to see it go! But the team almost has to RoShamBo to see who drives – at all. Hanna can’t believe she has to sit on this cart one more time and hear it not work. But she’s a good sport and even buckles her helmet, although she is quite sure it’s complete overkill.

And just like that, it’s over. Sadly, Pearls has now lost the _second_ gear cluster to the same fate: the mounting bolt has broken free and is spinning solo. Hanna was completely expecting this, and immediately jumps up and runs Pearls through the course.

Toby gets his game-face on and is ready to rock this course. Jiro backs him up, in case the cart bucks from over-torque.

Slackers gets a whole three feet before throwing a chain. It turns out their (second) gear cluster has also broken free. Gever thinks he can get in there and tack it down, though. We might look into an alternative mounting of those gear clusters next time…

The Platinum team has added yet another adornment. They will take no prisoners in this race.

The bungies, clamps and rope have held and Platinum successfully completes the course. With all that time for cupholders and hood ornaments, you’d think they’ve had put some footpegs on there…

The wind has come up and the carts are stored away. The modified glider still hasn’t been tested, and this is possibly the last chance (since it’s almost never windy in the morning). The keel duct tape is refreshed first, though, since it’s the one area that didn’t weather the few days storage.

The modifications to the control cage do seem to help the pilots keep in contact with the glider, but it still has a tendency to fly away without them. Note the increased surface area at the leading edge – overall the glider does fly a lot better with less tendency to stall.

It’s hard to say for sure, but as he ran by it seemed that Theo’s toes were just skimming the ground. He kept his legs moving (like a well-trained pilot should), and got lifted up for a moment here. Since it seemed like he finally got all the pieces together, it was agreed he should go an extra time to nail it and really fly.

There is a lot more latitude in the angle of the glider now, but when at speed the glider quickly dives if the nose drops. Theo finds this out the hard way, ending up rolling up into the wing (on the ground). None the worse for wear, his pants now have very mod tears on the front of the legs.

Leo has good acceleration, which gets the surface flying. It also demonstrates the incredible amount of flex the PVC has, which may be part of the problem in getting airborne.

The wind is a tad cross, relative the nicely mowed path we’re trying to use. Although mostly the kids manage to stay into the wind, if they don’t overpower a slight turn immediately then the glider quickly dives over. Luckily the ground crew is getting used to the scenario and quickly gets control of the glider.

Most who saw this flight say Leo got airborne. I have to admit, his arms are on the control frame, so it doesn’t look like he jumped. I do think he pulled his legs up, but afterward he kept running. I think we call this a flight!

As the lightest and possibly fastest of today’s test pilots, we’re all eager to see Toby’s flight. It looks like he actually got picked up for a moment here, and managed to keep running it down the hill.

The design of the control cage is specifically to allow the pilot to drop through if there is a problem (or the glider takes off out of control). Toby amply demonstrates this not once, but twice today. After slipping out and away from the glider, he tended to sprawl dramatically on the ground, enjoying the moment. (Then leap up and run off to try it again.)

Toby decides that Jacob should pick him up. Which is pretty easy for Jacob. Too easy. So Toby decides that Jacob should pick up Toby AND Samir. Looks like that is pretty easy, too, if you stack them correctly.

It’s time for dinner, so Isaac tries one last time. Things look good, but he doesn’t quite get lifted all the way. He does seem to have good pressure, though.

Instead of the classic left-hand turn, this time it’s a rightie. And Gever has been tracking, so if the glider accelerates he can keep up. So they both get caught up, but luckily neither go down. Except to dinner.

The Tinkerers get their final challenge of the week: after dinner, they have one hour to build a shelter to sleep in out by the campfire. They can use sticks, PVC, tarps, and miscellaneous other materials, but no power tools and the PVC can’t be cut. Bryan talks through some ideas with Toby and Tywen, although it’s not quite clear how this rope will provide shelter for them. Or maybe they string tarps over it to fit everyone?

Gever shows how cozy he will be in his shelter. We assume he plans to cover it, but you just never know.

Hanna, Max and Theo have a very simple design that has nice clean lines. Too bad they have to cover it up (although I guess that is the point).

Bryan has moved the crew from his rope trick to these vertical sticks. I don’t actually know how they’re standing up, especially with the tarp being shaken above them.

Robyn has wanted to try building a teepee, and Leo and Isaac are happy for the suggestion, since they got a late start (but warm showers). They get to use one of the Juniors tents as their ground cloth (although they probably don’t need windows in the floor).

After relocation to the camp-out area, Gever’s design has been expanded and extended. It’s sitting on a fileted paraglider.

Gever has always wanted to sleep in his paraglider, but I don’t think this is what he had in mind. So it’s good that it’s not his paraglider, but a donated unflightworthy one. Turned inside out. It ended up bigger than he needed, so the excess was left as a tail.

As soon as the cover is in place, Samir, Toby and Tywen run up to grab their bedding and get settled in. It’s quite secure – the flap is quite tight across the front, so they should be well protected from the fog rolling in.

Plenty of room for the three of them – hopefully no one rolls around too much and knocks over a supporting stick. Although unlike the little kids, between the level ground and better sealed sides, it’s not likely anyone will roll out during the night.

Leo and Isaac liked the teepee design, but wanted it to be asymmetrical – possibly to increase the interior space. Which seems to have worked, since it seems quite huge inside.

Maxine wanted the door flap to be more of a foyer (just like the pyramid created by the Juniors). So they added an arc to support it, but left plenty of tarp so the rope supporting the arc could be released and the door closed at night (or if the Rain/River God visited, which he did not).

Gever hasn’t installed his bedding yet, but the inside of his shelter feels like a cross between a bedouin tent and a parachute loft. I bet he has good dreams.

Since everyone ended up with a blue shelter (and the glider is stored nearby), it’s a bit hard to distinguish them, but they are (left to right): (upside-down glider), Gever’s paraglider dragon, Max/Hanna/Theo’s curved PVC hut, Samir/Tywen/Toby’s magic stick shelter, and Leo/Isaac’s asym teepee.

The closing night tradition (at least here at Elkus Ranch) of roasting marshmallows is warmly embraced. The night ends with an empty bag.