Tuesday, August 11, 2009

Flight of the garbasail [How-to Tuesday]

This is a guest post from Jesse Dill, a fellow scientist and good friend of mine from Berkeley. He's always coming up with brilliantly wacky ideas to try, like this one. You can find more from Jesse on his blog and his Flickr page

*****

I first found out about Garbasails when they were featured as Urban Dictionary's word of the day. A few curious clicks later, I was completely hooked on the idea. It's a simple formula: trash bags + duct tape + a lot of rope = one very large, very impressive-looking kite. My friend Harish and I decided to make it happen, and we hit the hardware store.

Duct tape, rope, and trash bags. Oh my.

Total cost for the materials was about $70. We thought we'd go medium-scale, with a 40-bag kite of single-ply, heavy-duty trash bags (“single-ply" means that we cut each bag along two seams so that it was just one layer of plastic thick).

Harish assembles the first row of trash bags

Assembly took three hours. We didn't have much space in the house, so there was only enough room to see one row at a time as it was added. After the panels were taped together, we knew that adding the reinforcing tape along the diagonals would require a bigger space to spread out the garbasail; fortunately it wasn't hard to locate an empty parking lot at the university on the weekend.


Our final garbasail design used 40 heavy-duty trash bags in an 8 x 5 arrangement, but with the longer edges making up the row that was five bags long. The result was a nearly square kite. One face of the kite had tape along all the edges, and the other face had a double-layer reinforcing line of duct tape along the diagonals and splitting each edge. The corners were reinforced with about six layers of duct tape, and the ropes were threaded through holes we punched at each of the eight attachment points (four corners, and the middle of each edge).


In the first test flight, we taped several of the ropes to lamp posts in the parking lot. We were stunned (and pretty delighted) to find that the kite caught enough air to rip through the duct-taped corners in just a few minutes.

Harish wrestles with the kite during a gust.

The power of the elements: our "reinforced" corners were no match for the wind.

The only camera we had on hand was my cell phone, but I did get a quick (albeit low-resolution) video of our test flight. Harish is holding down the corner that had already ripped at that point:

video

Fast-forward to the flight day: we’d toughened the attachment points by linking three rope loops through each of them and then running a single rope through the loops. This distributed the force across a wider area, and prevented the tear-through we had on the test flight.

Attaching handles to three short loops through each attachment site helped to keep the rope from ripping through the duct tape.

So how did it fly? Better than we imagined--with eight people holding onto the ropes, on a pretty windy day at the marina, we had serious trouble keeping a grip on the ropes. [Ed. -- And when we did, it was hard to stay on the ground.] I’d highly recommend wearing thick gloves when flying large garbasails, as the friction during strong gusts can be intense. We got several hours’ enjoyment out of the garbasail--though it did eventually tear to pieces, we all agreed that it was worth the investment.


It took a couple of tries before we got the garbasail off the ground. The red moped helmets were purely for decoration—garbasailing is a family-friendly activity.

The garbasail catches some wind at low altitude.


We also got some tips from a professional kite flyer. His main recommendations: include a ninth rope attached to the center, and buy some thick gloves.

The garbasail takes flight at the Berkeley Marina.

Can't get enough garbasail?
  • See the entire album of Wendy’s photos from the garbasail’s flight at http://bit.ly/garbasail
  • Check out the website of Josh Levine, an artist who created the first documented garbasails: garbasail.com

8 comments:

  1. i can't believe you guys were able to restrain that thing! even with 8 ppl!

    ReplyDelete
  2. It was a lot of fun to fly, too! I'm the guy on the far right in, well, all of these photos. With some kind of poles and a vent somewhere, this thing could probably get extremely high up.

    P.S. Hi Jesse

    ReplyDelete
  3. Hi I was drawn to your attempt and thought you did very well, as a kite designer and builder I know the forces that can be developed by even a small scale kite, if you are interested in a great easy to construct power kite I would suggest a NASA Wing kite, the pulling power developed by a 2.7 mt constructed of Balloon Ripstop Nylon developed enough power to drag myself and 3 fellow kite flyers along the ground for a considerable distance. Check out this site if interested.
    http://www.updyke.net/mukites/nasawing.html
    Have fun, kindest regards Peter Linn.
    http://peterlinnkites.blogspot.com

    ReplyDelete
  4. Thanks for the suggestion, Peter.

    ReplyDelete
  5. I envy your hobby, if not this damn job (

    ReplyDelete
  6. http://energykitesystems.net/Playsailing
    Notes are invited
    Notes@EnergyKiteSystems.net

    ReplyDelete
  7. Wow this looks like so much fun, I'd love to make one of these.

    ReplyDelete

Note: Only a member of this blog may post a comment.