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The Great Northern Concrete Toboggan Race
January 29, 2010 9:05 PM   Subscribe

For 36 years, engineering students from colleges across North America (and beyond) have aspired to succeed at winter's most prestigious, most arduous, most ridiculous challenge - to build and ride the world's fastest sled . . . made of concrete. Tomorrow, if you're in the greater Hamilton Ontario area, you can witness the Great Northern Concrete Toboggan Race yourself. Expect to see A fair warning however, spectators who stand too close might become part of the action.

Check out this long video for more good moments, but skip the dreadful two minute long narration in the middle.
posted by Popular Ethics (24 comments total) 15 users marked this as a favorite

 
You don't make friends with pants ON! You don't make friends with pants ON! You don't make friends with pants ON!
posted by DecemberBoy at 9:08 PM on January 29, 2010 [3 favorites]


Not canoes?
posted by ryanrs at 9:13 PM on January 29, 2010


DecemberBoy, I am now going to look for an excuse to use that chant...

Thank you Popular Ethics, for this reminder of why I miss hanging out with Eng students ... or don't miss it. Not sure which.
posted by strixus at 9:26 PM on January 29, 2010


That's even crazier than punkin chunkin.
posted by Chocolate Pickle at 9:35 PM on January 29, 2010 [2 favorites]


ryanrs: Not canoes?

At 1:27 in the "ridiculous challenge" link, you'll see what happens when you bring a concrete canoe to GNCTR.
posted by Popular Ethics at 9:38 PM on January 29, 2010


McMaster? I thought it was hosted by an engineering school. Does Mac have an engineering mascot to parade around at these kinds of events?
posted by GuyZero at 9:38 PM on January 29, 2010


There's enough snow in Hamilton?
posted by You Should See the Other Guy at 9:56 PM on January 29, 2010


Go Dal.
posted by Vectorcon Systems at 5:03 AM on January 30, 2010


Here for concrete canoes. Warning: the site is actually more ridiculous than the challenge.
posted by bluefrog at 7:03 AM on January 30, 2010


It doesn't look like having a roll-cage is much use if everybody just gets thrown out at the first bump!
But I'm curious, what sort of strategies have people tried to make a really fast concrete toboggan?
Is it just in the design, or the concrete(some sort of slick admixture?), or the quality of the formwork that moulds the concrete?
posted by Flashman at 7:27 AM on January 30, 2010


i'm in hamilton, and the teams have been staying at the hotel down the street from me most of the week. i was buying a bagel in the cafe yesterday morning, and some of them (team leaders?) were buying breakfast. they were dressed like "jamaicans" (yellow tshirts, rainbow toques, shorts) and explained that they were the jamaican bobsled team. i had NO IDEA what on earth was going on. now i know. thanks!
posted by janepanic at 7:34 AM on January 30, 2010


also, hamilton has no snow at all.
posted by janepanic at 7:37 AM on January 30, 2010


The race itself is about an hour north at the Glen Eden ski hill, which has plenty of (mostly artificially created) snow. We've had a very cold, if not snowy, winter so far.
And Mac is a damn fine engineering school, Guyzero. I did my first two years there.
posted by rocket88 at 8:02 AM on January 30, 2010


flashman: But I'm curious, what sort of strategies have people tried to make a really fast concrete toboggan? Is it just in the design, or the concrete(some sort of slick admixture?), or the quality of the formwork that moulds the concrete?

I ran a team that won numerous awards when I went to Carleton many winters ago. Unfortunately a lot of the "institutional memory" seems to have been lost. To encourage higher calibre sledding in the future, here is the Carleton secret formula for super-fast toboggans:
  1. Cast one slab, 2' wide by 8' long x 1" thick in a vacuum formed plastic mould. Long and narrow is best.
  2. Mold in a 1/4" raised section in the middle, leaving two 4" wide "skis" running the length of the slab. The toboggan will run on these skis over had-packed icy sections. The ski sections must have a flat bottom, I can't stress that enough - round bottom skis are very slow.
  3. Use caulking to round the edges at the front of the sled, leaving sharp edges at the back. This will help keep the toboggan pointed downhill. Don't bother with steering systems, they just slow you down.
  4. Make sure the mix is thick with short-chopped glass fibre strands to hold the slab together as it cracks. Use a thin composite reinforcement grid, not rebar.
  5. The mold release will leave thousands of little pockets on the bottom of the slab. Fill these with wax and polish smooth (this is allowed). Do not wait until race day to coat your slab - Few things are more frustrating than trying to melt wax over a 300 lb frozen heat sink.
Of course all of these rules can be ignored for the sake of having fun. Waterloo was famous for building giant spinning disc-type sleds in which the five riders sat with there backs to the center. And McMaster once built their toboggan entirely during the two-day opening ceremonies, casting their slab in the hotel bathtub.

The braking competition is another fun design challenge. I just got back from the 2010 race, which included one spectacularly scary end-over-end flip at the finish line that may have resulted in a few broken bones. That friends is why we put the brake at the back of the sled, not at the front.
posted by Popular Ethics at 9:57 AM on January 30, 2010 [36 favorites]


use caulking to round the edges at the front of the mold I mean.
posted by Popular Ethics at 9:59 AM on January 30, 2010


McMaster once built their toboggan entirely during the two-day opening ceremonies, casting their slab in the hotel bathtub.
Hilarious! What have you got to say to that, GuyZero? Sounds like an engineering school to me!
I'm surprised that Western has never won (though Universitat Stuttgart has!). Having grown up there, I know their engineers are responsible for some outrageous stunts on campus; I would've thought they'd be all over this.
posted by Flashman at 7:54 PM on January 30, 2010


use caulking to round the edges at the front of the mold I mean.

Yeah, I'm not an engineer and I still inserted that when I read it. How important is weight? What kinds of crazy aggregate can you use? Do you get into post tensioning or arched elements?
posted by BrotherCaine at 9:01 PM on January 30, 2010


Almost as cool as the concrete canoe competition. (blindingly ugly website)
posted by BrotherCaine at 9:02 PM on January 30, 2010


We never tried post-tensioning or other methods to make the slab more rigid. We used silica and sand for the aggregate, but only fines. The idea was that the slab *would* bend and crack during the race, so you try to make the concrete as flexible as possible, hence the fibreglass reinforcement. Waterloo once demonstrated a two-foot long test slab they could deform by three inches on either end ( but those geeks took things way too seriously :)
posted by Popular Ethics at 9:58 PM on January 30, 2010


Hey, are there any pictures of the actual toboggans? It's hard to tell what the concrete part looks like in the videos. Totally cool contest, though.
posted by bluefly at 6:40 AM on January 31, 2010


Searching "GNCTR" in flickr brings up a few good construction shots.

The concrete parts usually consist of skis or slabs only a few inches thick (though I once saw Concordia bring a full concrete shelled behemoth). These are joined to some kind of metal superstructure which helps keep the slab from flexing too much. Designing and building everything between September, when classes start, and January is a difficult task (you need to leave at least 30 days for the concrete to reach full strength too). The competition more than makes up for a couple less GPA and a few lost nights of sleep IMHO :)
posted by Popular Ethics at 7:03 AM on January 31, 2010


Popular Ethics "To encourage higher calibre sledding in the future, here is the Carleton secret formula for super-fast toboggans:"

"Later dudes. Let 'er rip, hang ten."

*FOOMF*
posted by Rhaomi at 9:52 AM on January 31, 2010 [1 favorite]


Almost as cool as the concrete canoe competition. (blindingly ugly website)

That's incredible, I'd not thought it possible but I guess I shouldn't have put it past engineers. Some of the details, particularly the reinforcement techniques of the area where the rowers sit, is just inspired.
posted by Civil_Disobedient at 7:50 PM on January 31, 2010


As a Carleton graduate, I saw this on the sidebar and was compelled to ask:

WHAT THE FUCK'S A GG?
WHAT THE FUCK'S A GG?
WHAT THE FUCK'S A GG?
posted by Kirk Grim at 7:47 PM on February 11, 2010 [1 favorite]


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