Chinese researchers said they have developed a drone with wings made from bamboo, making it 20 per cent lighter and considerably cheaper than a carbon fibre device, according to state news agency Xinhua. The bamboo-based unmanned aerial vehicle (UAV), which completed its maiden flight in the northern Chinese city of Tianjin last month, costs about a quarter of the price of carbon fibre cloth, it said. The savings meant that the overall structural costs of a drone made with the new material could...