Scientists working on a drone development programme created a “game-changing” methanol-powered fuel system that kept their UAV in the air for 12 hours.
It took them more than two years to get the FY-36 unmanned aerial vehicle to the flying prototype stage, said Zhang Wenyu, general manager of Feye UAV Technology, a Tianjin-based drone manufacturer that collaborated with the Dalian Institute of Chemical Physics, under the Chinese Academy of Sciences, in northeastern Liaoning province.
At 15 kilograms (33 pounds), the low-noise FY-36 can be lifted by an adult or transported in a pickup truck, and designers said its hybrid aerodynamic shape – with four vertical propellers – can allow it to cruise at speeds as high as 90km/h, or 56mph.
With a payload of up to three kilograms, the FY-36 was designed to perform tasks such as power line inspection, search and rescue missions, geological mapping and military intelligence gathering, but its power source is what stands out.
Its methanol fuel cell was designed to generate enough electricity for a flight time of up to 12 hours per charge. By comparison, a low-cost lithium-powered Chinese DJI Spark “selfie drone” can stay in the air for 15 minutes, while the professional-grade DJI Inspire 2 can barely top half an hour using a lithium-ion battery pack.
“There were tons of problems which had to be solved on the ground” before the FY-36 took its maiden flight in November, Zhang – who described the technology as a “game-changer” – said on Monday.
Fuel cell research at Dalian began in the 1960s, when the People’s Liberation Army launched a programme to develop an orbital spacecraft. That effort was scrapped in mid-1970s because of the high cost and complexity, but fuel cell development using substances including methanol, hydrogen and magnesium continued.
Over the years, the work provided long-term energy supplies for military platforms, including an unmanned submersible that can operate at a depth of more than 10,000 metres (32,800ft), according the institute’s website.
Meanwhile, developers tried to diversify into civilian sectors such as public transport and, most recently, drones.
Batteries that run on methanol – a plentiful fuel – are simple. When the colourless alcohol flows through the battery cell, its molecules are broken apart by a catalyst into carbon dioxide and water, a process that releases a huge amount of electrons.
Methanol, in theory, can store 70 times more energy than lithium-ion.
Achieving the real-life application of methanol fuel cells presented Dalian scientists with huge obstacles. Conversion of chemical energy to electricity was inefficient; methanol flow depended on air temperature, meaning a battery might struggle when there was a sudden increase in demand for power, and the cost of components, which used precious metals such as platinum, was high.
It took them decades to overcome these obstacles.
Before the FY-36’s maiden test flight, ground temperature fell to freezing and wind shear generated lots of turbulence. Whether the new power source could function properly in such adverse conditions was uncertain, but, according to Zhang, by Monday the FY-36 had completed 15 test flights.
“We still need to collect more data,” he said. “The result so far is very encouraging.”
The team expected to fine-tune the drone’s performance in flight before a commercial launch next year. The cost of the FY-36 was not clear, but Zhang said the price would be competitive for customers who ordered in bulk.
“We are definitely interested in the methanol battery,” said Xiao Yan, a manager at drone service provider Eagle Brother based in Shenzhen, southern Guangdong province, which was not involved in the project.
Endurance – time in the air – was a big issue in the UAV business, he said, and most of the drones in Eagle Brother’s lithium-powered fleet had to change their depleted batteries every 30 minutes.
The company – which provides drones to agriculture – had considered fossil fuels, Xian said. On a small drone, engine cooling was a challenge, especially under the summer heat. Adding a cooling system to a petrol engine would not only increase the cost of the drone, but cut the size of its payload.
To join the Eagle Brother fleet, drones were expected to lift as much as its lithium-powered models and come in at an “affordable” price. The company’s website showed drones capable of lifting 16kg.
“The current [FY-36] 3kg specification is too small for us,” Xian said.
China is not the only country developing fuel cell technology for flight. In Germany, Lange Research Aircraft has built the Antares E2, a 1.5-tonne methanol-powered plane designed to be piloted by humans or computer.
While it has not flown, the E2 was expected to carry more than 200kg (441lb) of payload at up to 40 hours aloft.
“In this weight range we are no doubt leading the world,” Zhang said of the much smaller FY-36.
Chinese companies have dominated the global drone market. Industry estimates suggested that DJI controls a share of more than 70 per cent.
In the military sector, Chinese drones are catching up with their US counterparts. The Rainbow series developed by the China Aerospace Science and Technology Corporation has been exported to customers including Saudi Arabia, the United Arab Emirates, Egypt and Pakistan by virtue of their low cost and competitive performance.
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