Iowa State University’s College of Engineering established the Lighter Than Air (LTA) competition during the fall 2011 semester, and students enrolled in Introduction to Aerospace Engineering have been working hard to construct successful LTA vehicles every semester since then in an attempt to place first in the contest. “The major objective of the competition is to construct a vehicle capable of successfully navigating an obstacle course that we design,” said Jim Benson, a teaching laboratory associate of aerospace engineering.
“The students are given a set of design constraints, but each design is wholly their own.”
The fall 2013 semester saw 245 students designing LTA vehicles—aircrafts supported by their own buoyancy or relative lightness—presenting their ideas, and building them with the supplied materials: balsa wood, propellers, motors, servos, glue and paint for the vehicle itself, plus a latex balloon with rings and clips to attach it. No outside materials are allowed, and the craft can weigh no more than 1 kilogram. Every piece is standardized so each team knows the exact weight of the equipment and can stay under the limit. The balloon can be filled only enough to lift up to 85 percent of the craft’s total weight.
Two main electronic devices are used to control the crafts. “The first is a standard radio-controlled receiver that controls the servos and motors on the aircraft,” said Matt Nelson, an engineer designer in the Department of Aerospace Engineering. Students operate a transmitter to send signals to control the devices. “
The second piece is a kill switch that is operated by the ground crew and referees during the competition,” Nelson said. The kill switch is used to cut power if a vehicle is out of control or enters a hazardous area.
Students must pass a design review before they can begin building.
Lighter Than Air is most popular in the fall semester with first-year engineering students because the project introduces them to the engineering thought process—not to mention the hands-on experience of actually building an object suitable for flying over, under, around, and through a range of obstacles.
A team of referees (wearing the requisite striped uniforms) follows the balloons as students navigate them through the course, while several judges evaluate aspects including aircraft construction and aesthetic appeal, and how well the craft performs required tasks on the course. A sound system technician, an emcee, a technical inspector, and a support team keep the whole process running smoothly.
Students learn some of the logistics and basics behind engineering, and they get good experience working with teams and equipment.