Buggy Racing at CMU

[Henry Julier]

Hello everyone.

Here at CMU there exists a race called Buggy. You can see pics of buggies at

http://www.andrew.cmu.edu/~fringe/buggy

The pics are big and I dont want to sap bandwidth here, so I wont post them. Let me explain how the race works-

The buggy fits one person inside (a very short girl) who steers and brakes. 2 runners push the cart up the first hill, then the buggy speeds down through a park, and the speed peaks at about 35. Then, it's a sharp righthand turn and 3 more runners push it back uphill to the finish. Total race time- 2 min. 9 seconds. The race is equally pusher strength and downhill speed.

Buggy's are built with carbon fiber, fibreglass and aramid honeycomb for the shell, and metal and delrin for many fixtures. The suspension on the two front wheels is this insane wishbone linkage which i can't talk about.

Now we get to the part I'm interested in... wheels. Currently, our buggies are using some big, thin profile scooter wheels from the Sharper Image. They're urethane and quite resiliant. But, they are heavy. The newest wheels that we have gotten (X2's) are grams heavier but worse the thane sucks. It's so dead I thought it was rubber, but, appearantly it's urethane.
On the bearing side of things, the axles are, I beleive, 3/8" (or so i was told.) They're bigger than skateboard bearings and are very slow.

So how would 101mm flywheels work in this application? Does anyone know of any fast bearings we could use? The best bearing lube for a 100 pound buggy? Can Geezer make titanium axles for us? Many questions. Give a look to the site (www.andrew.cmu.edu/~fringe/buggy) and tell me your ideas.

Henry
Fringe Mechanic

[Jonathan Harms]

Henry, I know you're a young'un, but have you seen any SkateBoarder mags from around 1977 or 1978? These "buggy" contraptions look amazingly similar to the "skatecars" of that time that raced at Signal Hill (CA) and Akron, OH (other places too? I'm not sure any more). None other than Henry Hester was one of the top competitors. (See http://www.longboard_skating.homestead.com/skatecar.html)

This probably doesn't answer your specific questions, but maybe you can get some sort of inspiration or information from it.

Can you modify or replace the axle so "regular" skateboard bearings will fit on it? If so, then the Flywheels idea might just, um, fly. Or maybe those big-ass Rolls Rolls wheels would work, if you could find someone willing to lend them.

Surely some of you speedier types (Chaput?) can help this young lad on his quest to hurl a young woman to her doom--oops, glory. I meant glory.

[Wesley Tucker]

Jonathan,

You're too late. I told Henry yesterday to find a set of Strokers for this contraption.

[Slappy Maxwell]

Duane is the only guy you need to talk to.

http://www.longboard_skating.homestead.com/duanes_skatecar.html

You can get the larger bearings at just about any mountainboard website.

http://www.offroadboardingmagazine.com/links2.html


Those are probably the Xootr wheels they are currently using. Their size and width makes them faster than anything you'll get in a skateboard wheel for that type of race.

http://www.xootr.com/xootr/nwheelassembly.shtml

<font size=-1>[ This Message was edited by: slappy maxwell on 2003-09-18 04:45 ]</font>

[Henry Julier]

Strokers are way to heavy for our application. Our buggies are steered with the front 2 wheels and have about 15 degrees of castor so that we can turn via camber thrust and not friction. Light stuff, even lighter if we can get TI axles...

H

[John Gilmour]

You could consider a tapered mast for the push rod so that on final shove you could store some energy in the flexing bow to propel the buggy further.

Also by putting a rounded cushion under the center of the woman inside, her shoulders could curve allowing the use of a narrower profile.

Match the durometer of the wheels to the surface and temperature. Do roll tests at various temps.