The Decathlon was designed by the Champion Aircraft Corporation, and is a derivative of the 7-series Citabrias. While the Citabria designs were and remain successful, and the 7KCAB variant of the Citabria had even added limited inverted flight capability, the Citabrias are not capable of “outside” maneuvers, those requiring significant negative-g loads. Pilots wanted an aircraft capable of more maneuvers, and the 8KCAB Decathlon was Champion’s answer.
Here's the manufacturer's specification page. Those who want to know a little bit more about the science and mathematics of search patterns can look here. It's not as simple as one might think. Nothing follows.