How Things Work: Buggy

As Buggy moves into the 21st century, this tradition rich in engineering and athletic excellence increasingly highlights cutting-edge technological innovations in science and engineering.

Racing a buggy involves three basic elements: mechanics, drivers, and pushers. Each buggy organization, of which there are currently 12 on campus, has a team of mechanics that is responsible for building, maintaining, and preparing its buggy for weekly practices and the race day in April.

However, in order to understand how Buggy works, and what makes for differing levels of competition among teams, it’s important to first understand what makes all buggies roll through the course.

Buggies can only be propelled by pushers (on the uphill portions of the course) and gravity (via the downhill “free roll” portion of the course). The buggies are maneuvered by drivers, who are members of the Carnegie Mellon community who are usually around five feet tall.

According to the Sweepstakes website (andrew.cmu.edu/~buggy), the racing vehicles cannot have any means of internal propulsion. This means that the vehicles cannot have any device “whose purpose is to store energy independent of the speed of the buggy (such as a geared flywheel) or whose purpose is to increase the forward speed of that buggy by adding kinetic energy.”

Teams interpret and implement mechanical systems differently, and this leads to changing levels of overall competitiveness and buggy team hierarchies.

While every organization has its own means of getting its buggy through the course in the quickest and most efficient way possible, there are standard parts to every buggy.

First, the outer cover, or “shell,” of a buggy — that which is seen from the outside and gives a buggy its general shape — is most commonly made of composite materials (fiberglass or carbon fiber), or in certain instances, metal frames.

The shell cannot exceed 15 feet in length or six feet in width. The shell must also be structurally sound to protect the driver inside.

All in all, the shell must be able to support a weight of 408 pounds.

While all buggy shells have standard dimensions, the buggy steering systems can be as diverse as buggies themselves.

Steering systems are controlled by the driver and not by the pusher or pushbar. The driver steers as she or he stretches her or his arms forward like Superman while laying on his or her stomach, holding on to some sort of handlebar that pivots left and right.

Some steering systems control a single front wheel, such as in a standard “trike” system with one wheel in front and two in back, or two front wheels and one back wheel in the case of a reverse trike system.

The ideal steering system is one that limits too much shaking, allowing the driver to easily maneuver through the course’s twists, turns, and potholes without losing control of the system.

The art of creating an efficient buggy braking mechanism, on the other hand, is one plagued by such troubles as brakes being too loose, rubbing the ground or wheel while the buggy is moving, and not releasing enough to give wheels sufficient room to turn properly.

Some teams’ buggies maintain brakes that stop the buggy by pressing against the ground (“drop brakes”), while other teams use brake systems that stop the buggy by braking against the wheel itself.

According to Sweepstakes rules, brakes must be “capable of stopping the rolling motion of [a] buggy.” The brakes must also be self-resetting, meaning that they must release braking power when a driver stops actuating them, and they must be equipped with locking devices.

The wheel technology of a buggy is almost as paramount to a team’s success as the rest of buggy technology as a whole.

According to buggy guidelines, three wheels must be in contact with the road surface at all times.

Wheels can be pneumatic tires, which are inflated before rolling like bike tires, rubber tires, or polyurethane tires. The different types of tires are believed to alter the smoothness of the course or speed of the buggy in various ways, many of which are specific to and kept secret by individual teams.

Drivers are the members of buggy teams that can make or break a race based on their driving accuracy and adherence to the team’s line, or desired path through the course.
Drivers enter the buggy by top or front hatches, or by the removal of the shell in its entirety from the base section of the buggy.

To keep drivers safe, they must be connected via a harness with D-ring carabiners (like those used when rock climbing) by a minimum of three different points to structural members of the buggy. This ensures that the driver’s movement is restricted in all directions in the event of an accident.

In addition to their harnesses, these team drivers are protected while driving by a required helmet, goggles, and gloves.

In incorporating such state-of-the-art, revolutionary materials, such as incredibly high strength-to-weight composites, Buggy continues to be just as trend-setting, technologically innovative, and unique as it was during its inception in 1920.