UCLA Engineering Students Design Boats for Rooftop Race
Senior Design Course Challenges Skills

Date: June 17,2004
Contact: Marlys Amundson ( marlysa@support.ucla.edu )
Phone: 310-206-0540

Anyone looking out onto the Engineering IV patio at the end of Spring Quarter would have seen an unusual sight. A crowd of students and onlookers gathered around a 16-foot tank of water to watch three unique boats racing across the pool. The competition was part of a mechanical and aerospace engineering senior design class, and included two timed runs by each team's boat, as well as a head-to-head race.

Boats built by Team Revolution and Team SSLA skim the water in head-to-head racing action.

Mechanical and aerospace engineering professor Pirouz Kavehpour, who joined UCLA last year, restructured the course this year.

"The class, as it was taught previously, was fairly open-ended," explained Kavehpour. "Students were asked to design and test shapes relevant to their fields. I wanted to give them an interesting task with deadlines."

At the beginning of the quarter, Kavehpour and his teaching assistants divided the students into teams based on their answers to an in-depth questionnaire. He wanted to ensure that each group would have students with strength in design, propulsion and building to create a fair level of competition. Kavehpour also appointed students as project manager and systems manager in each group.

The project managers set the schedule and made sure the finished product would meet all the specifications laid out by Kavehpour. They also were on hand to provide a fresh set of eyes to any problems that arose.

"It's sometimes easier to see a problem or solution if you're coming from an outside view," said Kristan Klinghoffer, the project manager for the Black Marlin group.

Each team was asked to design and build a boat no more than two feet wide and a foot in length. The craft had to include a mock radar tower that rose at least three inches above deck, and an observation pod beneath the boat. Within each team were three groups: one working on the boat's hull, another on the propulsion system and a third on the radar tower.

The systems managers ensured that each team's design groups were working in sync and that a change to one aspect of the boat was relayed and considered by all members of the team. They were also responsible for evaluating ideas and limiting the amount of risk the group would take in its design.

The most challenging requirement posed by Kavehpour was that the boats, which had to be self-propelled, could not be powered by electricity, eliminating tradition power sources such as batteries.

The three teams settled on three different methods of propulsion. The Black Marlin propulsion team led by Matthew Tharp explored several options, ultimately choosing carbon dioxide (CO2) as their source of power for the engine.

"We needed a source that would be relatively light, efficient and able to power the boat across the tank," explained Tharp. "We discarded springs and rubber bands, and tested rocket fuel but decided it was perhaps too easy."

Their boat, which had been running well earlier in the day of the competition, required last-minute adjustments before making it across the pool late in the competition. The boat with the fastest time, Revolution, made an end-to-end run in 5.39 seconds.

Team S.S.L.A. used compressed CO2 for propulsion of their craft. The Revolution group, which was not getting enough torque from their Stirling engine, switched to an estes rocket, commonly used in model rockets, for propulsion two days prior to the race.

The teams also opted for different materials for their hulls. Revolution's was made of alder wood and SSLA's of fiberglass. Although harder to manufacture, the Black Marlin team went with carbon fiber to build their hulls, which is both lighter and stronger than other possible materials.

"We started with a plug made of wood in the shape of our hulls to create a plaster mold," explained Kip Kojima, who led the Black Marlin's hull team. "Then we cut carbon fiber fabric and put it into the mold. After coating it with resin, we put the mold and fabric into a vacuum bag and treated it to harden."

Although the teams did not have to build a working radar system, designing a system that would be both light and aerodynamic presented several challenges. After testing other design options, including traditional wing shapes, in the wind tunnel, all three teams decided on a torpedo-shaped tower to minimize drag and weight.

As part of the course requirements, Kavehpour asked each team to submit a design report after four weeks and a testing report in the eighth week that compared results to date with their initial theories. These reports offered the students a chance to develop their teamwork skills, and to gain a full understanding of their boat's systems. Although learning to work in larger groups presented a challenge initially, many of the students in the course ultimately welcomed the opportunity to apply both their practical sense and theories learned while at UCLA to designing and building a working boat under rigorous constraints.