UAV-1 is the first of a series of CUAVA test campaigns using UAVs. The mission will assist in the verification and validation of the HyperSpectral Imager and Air@Wave payloads before their launch on CUAVA-1. An experimental GNSS receiver, designed to analyse reflected GNSS signals, and a commercial hyper-spectral sensor will also be flown on the mission. This talk will present a preliminary design of the payload, including a systems engineering overview of the requirements and subsystems as well as a detailed mechanical design of the payload adapter.