Tom Batchelor looks at a top-secret drone inspired by Cornwall’s seagulls
The skies above Cornwall will be that little bit busier soon, with the launch of a new drone. And while most of us consider seagulls to be pests, this drone simulates the birds’ flight by harnessing the wind – meaning that it can remain in flight up to ten times longer than conventional battery-powered vehicles.
The Hover Bird project, established by Falmouth-based aerospace engineering graduate Patrick Maletz, seeks to learn from nature by mimicking how birds gain altitude and cover great distances simply by using energy from wind currents. Most conventional drones struggle in even moderately unstable conditions, but in designing an unmanned aerial vehicle (UAV) that uses wind to its advantage, Maletz hopes his prototype could soon help serve some of the most remote and inhospitable parts of the world.
Not a normal drone
Falco Drone Technologies’ prototype has several characteristics that set it apart from regular UAVs: it can fly for much longer, therefore covering greater distances, and it achieves this even in strong wind conditions that would leave many of its competitors grounded. According to Maletz, the drone is as easy to control as a conventional quadcopter, and will include intelligent features that enable it to benefit from any wind strength or direction.
“The main thing holding back drones in key areas such as search and rescue, flying in mountainous terrain, some forms of agriculture as well as things like renewable energy inspection, is that they are really limited by how long they can fly for and what sort of weather conditions they can go out in,” Maletz told AIR International. “Hover Bird uses technology that allows the drone to make use of local wind and air currents to stay in the air, essentially flying a bit like a bird would. So instead of fighting gusts, the drone is able to supplement the lift it gets from its motors using wind and air currents, which dramatically increases its airborne time.”
While it undergoes testing, the drone will be controlled by a human being. But eventually, there are plans for all the controls to be fully automated.
“The eventual goal is that the drone will know which way the wind is coming from and know how to best optimise orientation in the air to fly as efficiently as possible,” Maletz explained. “There are some other challenges, such as control problems. For example, achieving stability in gusty winds is tricky, but they are technical challenges that should be easy to overcome with more time.”
The detailed design package is being kept under wraps while Maletz applies for a patent. He submitted an initial proposal to the patent office last year, but must wait until October until it is approved – in the meantime, any information about its design which becomes public cannot be added to the patent application. So for now, the exact look of the drone, and any photos of it, must be kept secret. But what we do know is that it is a quadcopter design, meaning there are four propellers enabling vertical take-off and landing, as well as hovering capability. The difference is that the drone has an extra wing mounted in a “novel way” that allows it to supplement the lift from its four propellers using wind and local currents. But the wing itself does not change shape during the flight. “I came up with the idea by taking inspiration from nature,” explained Maletz, whose day job is in humanoid robotics. “My initial proposal was to make a drone that would be good for ski patrollers. That was quite a few years ago. It was a vague idea that it would be able to look for people in the mountains or drop dynamite for avalanche control.
“But I didn't get very far because I quickly realised that the mountain environment was very harsh on the drone and you wouldn't be able to take off reliably.” He continued: “I live in Cornwall and spend a lot of time in or near the sea. You tend to see a lot of seagulls and other birds fly around and just from watching them you realise how efficient they are. If you actually watch birds, they tend to make use of the wind currents and updraughts to stay in the air, and they are barely using any energy at all. So I pursued that and came up with the initial Hover Bird design from those first principles.”
In the spring, work was completed on the first prototype of the drone, and land-based testing has been under way with “pretty good success”. The next stage in the process is to gather the data, refine the design and then next year put the drone through application-specific testing.
This will include a test flight in collaboration with Marine-i, which helps grow marine technology businesses in Cornwall and the Isles of Scilly. It will see the UAV conduct an inspection flight of a turbine in Scotland.
Located off the coast of Fife coast, ORE Catapult’s Levenmouth Demonstration Turbine (LDT) is an offshore wind turbine dedicated to helping companies to research and develop innovative technology to support the renewable energy sector. It is hoped the Hover Bird’s unique abilities will demonstrate that it can fly with the required stability around the structure for longer than other drones are able to.
Use and stumbling blocks
Once proven, the technology could be leased out to companies that want to integrate it into their operations, primarily in agriculture, energy and the emergency services. “We're not developing full end solutions, there are a lot of people already doing that well. What we are aiming to do is provide people with more capable flight vehicles that they can integrate into their own payloads,” said Maletz, who has worked on the project single-handedly since the company was formed last April.
Time and money continue to be the limiting factors for the project, although Falco Drone Technologies has received a grant from Agri-tech Cornwall to develop the first prototype, alongside support from AeroSpace Cornwall, a research, development and innovation fund, and Marine-i. Maletz has received more than 12 hours of one-on-one business consultancy, including time with an academic from the University of Plymouth and help with the submission of a provisional patent application. “I've got my normal job as a mechanical engineer as well so between those two things I'm quite busy!”
The drone is electrically powered, though there would be nothing to stop developers integrating it into a hybrid propulsion vehicle. Manufacturers of conventional drones must weigh up the additional flight time that a larger battery offers with the associated reduced payload. But the Hover Bird’s design allows it to overcome that problem. “Drones use about 95% of their energy just to hover and stay in the air which means they tend to have a really low flight time,” Maletz explained.
“Twenty minutes or half an hour tends to be the norm these days, and it's incredibly difficult to increase that because if you add a bigger battery for longer flight times you get diminishing returns, with the bigger battery being heavier meaning you need to reduce your payloads. You would come up to what is quite a hard limit which is linked to the energy density of modern batteries.
“However, if you can supplement any of the 95% of energy – or even all of it – with wind, you're looking at really big increases and some of the simulations show that the initial prototype of this drone should be able to achieve around three-and-a-half hours of flight time in optimum conditions. That is a huge increase potentially.” With design tweaks, the drone’s endurance could be even higher.
Swift but safe
The majority of commercial drones can operate safely in winds of 10-30mph, with the top speed of the UAV determining exactly what the maximum wind tolerance of each vehicle is. However, because the Hover Bird is designed to actually benefit from the air currents, it can fly in much stronger winds, with the prototype expected to achieve an upper wind speed limit of at least 45-50mph. “Quite how close to that this drone will be able to achieve depends on the control system,” noted Maletz. “But 50mph is very achievable, and potentially even more. As you have supplemented all of the lift that the motors need to provide [with the extra wing], you can use all of your motor power to fight against the wind, which really increases the upper limit of what you can fly in.
“Normal drones tend to struggle in 20mph wind and most are pretty much grounded in 25mph winds. There are some that can handle more, but they tend to be really big and heavy and extremely inefficient. At the higher limits you start reducing the flight times quite a lot because you are fighting against the drag of the gusts of wind.” By blending the benefits of fixed wing and multirotor aircraft, the Hover Bird may soon offer a solution for companies operating drones in some of the harshest and most unpredictable environments. If all goes to plan, and tests this summer yielded the results Maletz was hoping for, his UAV could revolutionise the drone market with increased flight times, higher payloads and unmatched
Drones at sea
Marine robotics company Ocean Infinity, which is based between Austin, Texas, and Southampton in the UK, is working on a project that would allow aerial drone swarms launched from an uncrewed ‘Armada’ of marine robotic vessels to carry out offshore wind farm inspections.
The programme, running in partnership with the University of Portsmouth, Airborne Robotics and Bentley Telecom, will rely on 5G and satellite connectivity to provide drones that assess turbines out at sea, removing the cost and safety risks associated with human inspections.
The robotic vessel will act as a launchpad for the drones and will enable the aerial vehicles to recharge and transmit their data to shore. Oliver Plunkett, Ocean Infinity’s CEO, announced in August that the company had acquired Oxfordshire marine geotechnics specialists Geowynd, which he said would help it “move closer to mobilising Armada”. He added: “There is no question that renewable energy is the key to a sustainable future. Striving for a cleaner and greener future is hugely important to Ocean Infinity; it drives everything we do.”
The company plans to expand its fleet to 17 robotic ships over the next two years, and the £1.6m Drone Swarm for Unmanned Inspection of Wind Turbines (Dr-SUIT) project will be ready for a full demonstration as early as 2022.
Drones in archaeology
Drones are a particularly useful tool for archaeologists. They enable stable, low-level aerial photography and can be rigged with specialist cameras and sensors, including multispectral imaging units and even laser scanners, helping researchers uncover archaeological sites and landscapes like never before.
UAVs are increasingly deployed to carry out tasks such as monitoring sites and recording excavated features, as well as helping generate accurate 3D models.
Historic England, the public body that looks after the country’s oldest buildings and monuments, has supplemented photos obtained using masts, kites, balloons, helicopters and aeroplanes with drone-acquired imagery for more than a decade.
In the US, Professor Jesse Casana, who chairs the Department of Anthropology at Dartmouth College in New Hampshire, was part of a team that used UAVs to observe an archaeological site in southeastern Kansas believed to be the location of Etzanoa, a major settlement reportedly encountered by Spanish conquistadors.
Using drones, the team captured high-resolution thermal and multispectral imagery, revealing a large, circular earthwork that researchers said may have been a ritual or defensive structure.
Speaking to AIR International, Casana said archaeologists had been “early adopters” of drone technology, which had now become “fully integrated in the standard part of our toolkit. In terms of very close-up, frequent, high-resolution mapping and imaging features, the imagery that you can get out of a drone makes it ideally suited for the needs of many archaeologists”. He added that new, more advanced sensors fitted to UAVs were giving archaeologists a much clearer view of their excavation sites.
“If you just take a picture of the ground with a normal colour camera, you see what you would see if you were in a plane looking down. But there’s a lot of archaeological features that you might not be able to detect with your eyes. A dry stone wall, or a ditch, or an old house base, they might be below the ground. And there are subtle differences in the way that archaeological features might affect the growth of plants on top of them, so that is something that you often can’t really see just in a normal aerial photo.
“Also, a lot of the things that we’re looking for are temperamental in terms of when they are visible. So you have to be there just at that right moment, at night, or seasonally, in order to record it. And if you’re reliant on scheduling a plane or something like that to fly, then you might miss that window. So the drones allow us to collect whatever resolution we want, whenever we want. And that’s really critical to making it work,” he explained.