Tiger Transit Takes to the Skies

Academic year 2017-18 was Princeton Radio Control Club’s first year to participate in the Design-Build-Fly (DBF) competition hosted in Kansas by the American Institute of Aeronautics and Astronautics (AIAA). The challenge: to design a robust, serviceable aircraft capable of carrying a variety of payloads in a wide range of mission profiles. The competition: 100 other collegiate teams from all over the world.

Flight videos from previous competition years revealed that around half of all teams crash their airplanes. This is often due to a poor, unstable or weak design or an aggressively optimized design with unfamiliar flight characteristics. These planes need only a gust of Kansas winds or an inexperienced pilot to send them down. So we set a goal to design a stable, conventional aircraft with predictable flight qualities.

Our aircraft, named “Tiger Transit” after Princeton’s shuttle buses, has a wingspan just over 3 feet and a gross weight of about 3 pounds. It has seats for 6 “passengers” (represented by 1–2-inch diameter bouncy balls) and can carry a half-pound payload block. It was constructed with laser-cut balsa wood and birch aircraft plywood in high-stress areas. The wing planform has a taper ratio of 0.5, which nearly maximizes the lift generated for the wingspan. Per the contest rules, it is powered by a Nickel-Metal Hydride battery, and cruises at roughly 30mph.
The competition has an exciting atmosphere of both competition and collaboration. Each team is optimizing their plane to maximize its scoring potential, but everyone is friendly and teams frequently assist each other. On the first day, we were hurrying to finish the final details of the plane and repair damage from a test flight. Embry-Riddle Aeronautical University’s team offered to help us, and they expertly applied Monokote covering to our spare wing. We really enjoying seeing the wide variety of aircraft and discussing design strategies, software, and materials with other students.

The competition was held at Cessna Aircraft Field in Wichita, Kansas, from Thursday, April 19 to Sunday, April 22. After passing Technical Inspection on Friday, we flew Mission 1, the demonstration flight. Saturday brought rain, but also calm winds, and we completed Mission 2: a high-speed delivery of all six passengers. On Sunday, the winds were a little higher, but we decided to attempt Mission 3: a long haul of passengers and cargo. During the propulsion system run-up, the battery appeared to be dead despite charging it overnight. We quickly reset the motor controller to let it run on lower voltage, and took off. The plane lazily climbed to altitude and completed one lap, after which we decided to land. Though we did not fly as many laps as we wanted, just completing the final mission bumped our score up into the top quarter. As a rookie team, we were just happy to have completed all missions while keeping our plane
intact. Tiger Transit has an easy retirement ahead as a club promoter, performing leisurely demonstration flights to show off what the Princeton Radio Control Club can do.

PRCC is about the design, construction, competition, and enjoyment of all types of model vehicles. The name “Radio Control” in Princeton Radio Control Club was chosen over “Model Airplane” or “Aerospace” intentionally to include model cars, trucks, boats, helicopters, or even battle bots in the scope of where the club may go in the coming years.

We would like to thank the Keller Center for funding our project materials, and the MAE department for providing travel funding and wonderful facilities for designing and manufacturing Tiger Transit. We would also like to thank Luis Gonzalez, our faculty advisor. Finally, we thank the AIAA, Cessna/Raytheon Missile Systems, and all the contest administrators that make this event possible.

Tristan LaCombe
President, PRCC