HUMAN POWERED VEHICLE ROLLS ON
When the spring of 2011 arrives, it will mark the completion of a lengthy process for those involved in the Human Powered Vehicle Competition (HPVC). Spring 2011 is the targeted date for the HPVC team to enter their first competition after what will total nearly three years of planning and development. A tricycle design fitted with a polygonal shaped fairing will likely represent UNL’s American Society of Mechanical Engineers (ASME) chapter at their first appearance in the competition, which is organized and conducted by ASME.
According to the ASME Web site, the HPVC provides an opportunity for undergraduate and graduate engineering students to demonstrate the application of sound engineering design principles in the development of sustainable and practical transportation alternatives. In the HPVC, students work in teams to design and build efficient, highly engineered vehicles for everyday use—from commuting to work, to carrying goods to market.
This was exactly the type of competition UNL’s ASME chapter was looking for in 2008.
“There really wasn’t another large, hands-on project for students to work on,” said Tom Frederick, leader of UNL’s HPVC team. “The hardest part has really been getting it going, getting a base design and getting the first bike done.”
He added, “Other universities that compete usually reuse and improve upon a lot of the components from previous years so once we have the first competition bike done, we’ll have something to improve upon in following years.”
As a basis to start from, the HPVC team constructed what has become known as the Frankin Bike. Composed of two chopped bike frames and a long steel beam welded between them, the Frankin Bike is nearly nine feet in length. The extremely long wheel base in the design made balancing, let alone piloting the vehicle, exceptionally difficult. Despite its flaws, the Frankin Bike gave the team a benchmark to work from in developing their first prototype competition vehicle.
After considering how difficult the Frankin Bike was to balance, the team chose to build the prototype vehicle as a tricycle to provide more stability, with two wheels in front and one in the rear. A much shorter wheel base than the Frankin Bike’s was a major design priority for the team to allow for tighter, quicker turns with the vehicle. To make it more comfortable and easier to pilot, an adjustable seat was also included in the design to accommodate different drivers.
Coroplast was chosen as the material to construct the fairing because of its lightweight and low cost. Coroplast is a corrugated plastic and because of the nature of the material, the fairing will be polygonal in shape. Development of the fairing design was done with the use of Solid Works Fluid Analysis. One of the most important design considerations for the fairing is the tail section, because drag must be minimized.
The other critical consideration in the fairing design is how drivers are able to enter and exit the vehicle. A hinged door or a removable section of the rear portion of the fairing are the two designs still being considered by the team. The third consideration in designing the fairing was whether or not to extend it wide enough to cover the front wheels. This is also still being considered by the team.
Two different formats are used for the competition. The format is selected by the host university while taking into account the space needed and the space available to host the competition.
The endurance format consists of a two-hour timed race where the team that covers the greatest distance is declared the winner. Teams will rotate drivers during the race to meet the required number of drivers in the competition. Distances covered are around 65 km. The other competition format used is a sprint event. Teams begin from a standing start and have 500 meters to run their vehicle, with the fastest 100 meters taken as the team’s time. Teams are required to have a minimum of three male riders and one female rider, all of whom must pilot the vehicle at least once.
HPVC is still looking for students who would like to participate in the design, construction, and competition. For more information on how to get involved, contact ASME through their Web site, http://asme.unl.edu/home.html or through the Mechanical Engineering office located in Scott Engineering Center, room N104.