Apex Buggy - Phoenix Build 

 

Sweepstakes (aka. "Buggy) at Carnegie Mellon is a human powered vehicle competition. Born from a long-standing tradition at the university teams of 5 runners push an un-powered gravity vehicle containing a 6th team-mate who drives the buggy. The race consists of 2 uphill segments where runners relay the buggy, and a free rolling downhill segment where the vehicle is steered by the driver and can reach speeds in excess of 40 miles per hour.

 

Yes, there really is a person in there. No they aren’t controlled by robots.

 

I had been participating in the sport of Buggy since 2009 when I enrolled at the University. Serving as a Mechanic and then a Chairman of the Organization "Pioneers" in 2010

Apex Buggy was founded after Pioneers was unable to complete their fundraising goals or recruit enough personal to run a team.

 

In Fall of 2011 after a mutual agreement was reached the resources and space allocations for the Pioneers buggy team were transferred to a fledgling team "Rez Buggy", later named "Apex Buggy" 

I served as advisor to the new buggy team during their first year assisting them with the management of running a student organization including establishing bylaws, fund-raising and communicating with the university. 

In Fall of 2012 I was elected co-chair of Apex buggy alongside Connor Hayes. Our responsibilities expanded to include the fabrication of a new buggy vehicle to be name "Phoenix". The documents below come from my design notes about that build process. Phoenix was completed in time to race during the Spring 2013 Sweepstakes event. Phoenix is still racing to this day and can be seen out all weekends that buggies are rolling on the race course located on Flagstaff Hill between Carnegie Mellon's Campus and Phipps Conservatory. 

This project would not have been possible without the entire Apex team​ all members and advisors made significant contributions to the build.

Buggies are often designed to fit one specific driver, their dimensions scaled to allow the driver to fit inside while also being as light as possible​ and using the least possible materials. 

Phoenix's design was based on a buggy called "Chaos" operated by the Pioneers team. It was scaled to fit two different drivers taking measurements from each and creating a more versatile vehicle.

For this buggy a male mold was created so that it could be wrapped in carbon fiber, this mold constructed of insulation foam and body filler was sacrificial and would be extracted from the inside of the buggy after the layup process was complete. The surface finish of the mold was critical as it would determine the surface against which the driver would operate the vehicle. Here we see the driver posing next to the mold. 

Most if not all buggies currently in use are constructed using Carbon fiber or fiberglass layup techniques borrowed from Aviation and Ship Building. Here we are milling aluminum parts that will be embedded inside the carbon fiber monocoque that makes up the outer shell of the buggy. The aluminum 'hard points' allow the mechanics to securely fasten the internal mechanisms of the buggy into place, ensuring proper alignment of wheels and steering systems and preventing damage to the sandwich of carbon fiber sheet and nomex honeycomb. 
 

The baseplate of this buggy was constructed of end-grain balsa-wood. Allowing for greater rigidity and vibration damping a technique borrowed from boat construction. 

"Apex invited CMUTV to document critical parts of their build process, a move unprecedented in buggy history​ up to this point"

Buggy is usually a sport cloaked in secrecy. Because it was possible to gain a competitive advantage though technological breakthroughs most teams would keep their process secret. 

This made it especially difficult for new teams entering the sport to fabricate their own vehicle. 

Apex decided to do everything in their power to open-source their process, tools, techniques, failures, and methods so that information would be available to new buggy teams in the future. 

The video embedded in this page is the result of many instances of CMU TV coming down to the shop to document the process of fabricating a buggy.  

After the completion of the shell and the extraction of the mold the team began the assembly process. All of the parts that encompassed the control scheme for the buggy including steering, brakes, hatches, windshield, and push-bar needed to be affixed, tested, and adjusted. 

Critical areas around the hatches, and edges of the shell were reinforced with a mixture of fiberglass beads and epoxy resin to provide better abrasion and chipping resistance. Some cosmetic body filler was also added before the painting process.

​After assembly the buggy was ready to be put through its paces. Buggies must pass an annual capabilities test in order to qualify for weekend rolls practice. These tests ensure safety for the driver and the structural integrity of the vehicle, the requirements can change from year to year so Phoenix was built to be adaptable and to last. 

Pictures below are from the first 'Capes' test of this buggy.  

 

Ethan Gladding