Flame Aegis is a fire-fighting drone designed to combat high-rise building fires in urban areas. This product has been requested by the Gezamenlijke Brandweer, and certain stakeholder requirements have been imposed. There are further regulatory constraints at both national and European levels. A 150 kg drone with a capacity of 40 L of water was designed in the end. The water can be delivered by spraying at a rate of 150 L/min through a nozzle or by dropping the contents of the tank within 2 seconds. The drone is able to perform a 15-minute mission with a 5-minute turnaround time.