Redwood Challenge 2011 Report

Finally got around to writing up last year's Redwood Challenge Report... The challenge took place on Dec 11, 2011.

Part 1: More Balloons!

The Idea: Balloons have worked well in the past at getting lift. The primary challenge was wind, second challenge was dealing with lines and tangles. I decided to take a shot at dawn when wind would be minimal and use fishing gear to manage the lines.

Setup: To streamline the top of the line I went with one latex balloon, the biggest one they had at the party store, thinking it would give the best lift-to-messiness ratio. I bought two surprisingly cheap fishing rods, reels, and line earlier in the week. They seemed perfect. I got up way too early.

Results: It actually went very well...

- First attempt: absolutely no wind, balloon went 80 feet straight up. For the first time I had the challenge of how to get the balloon over to the tree. I reeled the balloon in and ran inside to get a second line person, pictured here.

- With her help we got the balloon pretty much into the top of the tree. The "Put a helium balloon in the top of the tree" sub-challenge is solved!

Of course, having achieved that, I wanted to try to get the next step with it -- putting an anchor point at the top of the tree that could be used to hoist up other decorations. There we didn't have much luck. Long story short, having fishing rods and reels to manage the lines was an immense improvement over last year but I didn't take it far enough -- one critical piece I was missing was the spinner things that fishing floats have to keep lines from getting tangled when the float spins (kites have them too, and probably just about every other application that deals with lines and wind/fluid movement). Without those anything we hoisted up using the balloon got hopelessly twisted creating a lot of extra friction. The other problem was being able to separate the balloon from the payload at the top. I did this with a piece of scotch tape loosely fastened that would come undone by yanking the line. That worked but was pretty fiddly, something more reliable would help. After 20 minutes of screwing around with this and losing a couple of lines in the tree the wind came up and it was game over for balloon approaches.

Conclusion: Helium balloons remain the undisputed champion of height, and the first technique to put an item in the top of the tree! Best known mode: at dawn on a calm day, a single large balloon, fishing gear to manage lines, and use those swivel things if you want to try to carry up a loop.

Part 2: Slingshots, baby

So, with spirits high from the new height record, and munitions bags full, we moved on to the main event -- projectiles.

The Idea: Hitting tennis balls worked well, slingshots should give similar or greater power with much more improved aim.

Setup: I bought a Trumark slingshot on Amazon. It has a very satisfying grip and metal brace that pushes down on your forearm as you pull back the elastic. They did not have this when I was a kid. Or I didn't anyway. This design made me much more confident that I would not take a slingshot in the face at some point.

I had been practicing through the week to get consistent with aim and power. The main challenge was that the slingshot was designed to shoot BBs and I wanted to shoot a racketball. Keeping the leather strap centered on the ball throughout the acceleration phase of the shot was tricky. Because of the weight of the racketball power was also a problem. I could shoot 80 feet horizontally but wasn't sure I could do it vertically. I tried to think of smaller ammo that would still be safe. Golf ball? Rubber bouncy ball? They seemed too hard to launch into suburbia so I stuck with the racketball.

Results: The good news is accuracy was much easier to achieve than with a tennis racket. The bad news is we were significantly underpowered (as we were with the racket too). I could get maybe 50 feet up. We wanted more.

The limiting factor seemed to be arm length so I rigged up a two by four and a ladder to get a longer stretch distance. I armed the slingshot and held the racketball with both hands, pulling it back along the two by four, aiming and releasing. It was clear that the slingshot was not designed to be pulled back much more than average-man's-arm-length. After another 8 inches or so the rubber became stiff a-la high school physics experiment. Still, this probably got us another 10 feet of height and was even easier to aim. Visions of the slingshot hitting my face were pretty acute here so I wore protective glasses and gloves generally tried to stay out of the way. After a few shots the rubber broke loose from the slingshot, causing no injuries and neatly ending the slingshot phase.

Conclusion: Slingshots are awesome. Aim was easy. Need bigger slingshot.

Part 3: Casting

The Idea: We've got fishing gear. It's made for casting stuff long distances. Let's do some casting!

Setup: We already had all the gear. We drilled holes through some racketballs and threaded them with fishing line, then went to the park to practice casting into an empty field, going for height.

Results: Casting racketballs as high as possible with precise aim turns out to be really hard. The other, unanticipated problem was when the line hit the tree it tended to snag on a branch sending the racketball into an accelerating spin around the branch. In one case we were able to retrieve the ball. In the second... it's going to be up there for a while. We did get one good shot up at 50 or 60 feet, but it's difficult to get any repeatable success.

Conclusion: Not very successful. Maybe someone with more practice would have better luck (though who practices casting straight up?) The payload spinning around a branch is a problem that isn't fully understood and is likely a more general challenge for projectile approaches.