Unmanned aerial vehicles (UAV) or drones, being able to easily fly over mountains, rivers, lakes, etc., are very attractive for many applications. However, there is still a major drawback, power limit. Currently the UAVs or drones are mainly powered by either gasolines or batteries. The gasolines are highly dangerous for the possibility of explosion and cause sever damages if the drones accidentally crash. Batteries are relatively safe, but only provide very limited time of flight, mostly less than 30 minutes for vertically taking-off drones. Hence, it is very crucial to develop the technologies that enable multi-copters to continuously fly several hours. In this product, we combine the domain knowledge in the areas of photovoltaics, control, and communications to significantly extend the flight time of drones. We expect to achieve several hours of continuous flight, so drones can be used to explore the frontiers that people have never gone before.