Why are we writing about this topic:
When you think of aviation in the Netherlands, you quickly think of Schiphol. But while at Schiphol you mainly stand in line for your suitcase, Twente is working on the future of aviation. For this article, we spoke to three parties, each doing this in their own way.
The aviation industry still has a major sustainability challenge to face. In 2020, the Dutch aviation sector emitted 7.6 billion kilos of CO₂. The more kilos that enter the air, the higher the CO₂ emission. So: the lighter the aircraft, the lower the emissions. The Enschede ThermoPlastic Composites Research Center (TPRC) researches the application of thermoplastic composites to aircraft structures.
The latest planes from Boeing and Airbus already consist of half the weight of composites. Thermoplastic composites – fiber-reinforced plastics – are light, strong, easy to process and recyclable. In the transition to a more sustainable industry, it sounds promising. However, much is still unknown about the physical mechanisms, especially in connections between different materials such as metal and thermoplastic composites.
Lightweight design for more sustainable transport
When Technical Director Sebastiaan Wijskamp started at TPRC in 2015, the research was in an exploratory phase. “Then we looked at how we could incorporate the material into less stressed parts of an aircraft. Now our focus has shifted to use in the primary structure in heavily loaded parts. In recent years, there has been some sort of shift in acceptance. An aircraft must be reusable and produced in a sustainable way. ‘What do we do with production waste?’ is a much more important issue for aircraft manufacturers now than it was ten years ago.” It is now known that thermoplastics can be processed more energy-efficiently into a final product.
The TPRC consortium now consists of 21 partners from the Netherlands and abroad. About seventy to eighty people attend the biennial Technical Advisory Board (TAB) conference. “You can see that knowledge is gaining ground. We cooperate with each other’s competitors. It is possible because we are an independent research center that solves fundamental problems.”
“In recent years, there has been a kind of shift in acceptance. An aircraft must be reusable and produced in a sustainable way. ‘What do we do with production waste?’ is a much more important issue for aircraft manufacturers now than it was ten years ago.”
Sebastian Wijskamp, TPRC
TPRC originated from the production technology department at the University of Twente, which was particularly active in plastics and thermoplastics. Aircraft component manufacturer Fokker and Toray Advanced Composites funded the university’s research. “For example, thermoplastics have become a spearhead for Twente, and we have built up a wealth of specific knowledge and companies in the region,” explains Wijskamp.
When the airline Boeing also reports, they decide to establish a research center together. Partners invest together in research that they would otherwise have to carry out independently.
There is an increasing focus on sustainability. Nevertheless, Wijskamp notes that there is a gap between basic research and application. It takes time to translate all the knowledge that TPRC gathers into large-scale applications. “It works best in the places where the planes are actually built. But with companies like Fokker, the expertise from the University of Twente and Twente Airport, we have a very solid ecosystem. Both nationally and internationally. It also radiates Kennispark Twente, of which our research center is a part. We all benefit from that. We share knowledge and progress with each other.”
H2 Hub Twente
Fuel is another important point of attention in the transition to more sustainable aviation. H2Hub Twente is a physical place where entrepreneurs and education work together on research, development and application of hydrogen technology. Here, too, the aim is for the 25 partners to work together in relation to the technical development within hydrogen, so that not everyone has to reinvent the wheel for themselves. Five projects are now running, of which the H2 Big Drone project is one.
Start-up Drone4, part of Machinefabriek Boessenkool, is leading the way. The name says it all: At Boessenkool, they mainly develop machines. “Drone4 is really an outsider,” admits Eelco Osse, owner and CEO of the company. “We work a lot with farmers, for example with the development of an electric tractor. They prefer that as little earthwork as possible takes place on their fields. Then there is only one solution: the tractor must be airborne.”
Hydrogen: cryogenic or ‘under pressure’
The drone must fly on hydrogen. Fossil fuel is actually “no longer an option” in this day and age, according to Osse, and battery development is too slow. Hydrogen also has a high energy density, so it is not difficult to transport a lot of energy.
And so the start-up, together with Saxion University of Applied Sciences, is developing a drone with a wide range for agricultural applications, defense, transport and logistics. The focus is on increasing the reach.
The company has not yet decided whether they will use pressurized hydrogen or cryogenic (very cold, liquid hydrogen). Volumes are still quite high under pressure. As an illustration: a drone now has a diameter of about four meters, in order to carry enough fuel, a tank twice as large must hang below the drone. But cryogen also has disadvantages. It is more expensive and riskier.
Legislation and regulations as a major obstacle
One of the biggest challenges Osse faces is legislation and regulations. “An electric variant of the agrodrone has been technically ready for two years. But commercially nothing is allowed. On the one hand, we are at the forefront of development, but at the same time we are also lagging behind due to regulations.”
According to European laws and regulations, only drones weighing up to 25 kilos can get a certificate, while Boessenkool’s drones are already heavier than that without cargo. So the company is at the mercy of use-case certifications. “We have to describe in detail to RDW what we want to do with the drone. And then we haven’t even dealt with hydrogen as a fuel in terms of regulations, that phase has not yet come. The hydrogen hub plays an important role, for the authorities, who decides the rules, also sits at the table there.”
Twente Airport wants to be a testing ground for innovations in aviation
Twente airport laid the foundation for the region’s strong offer in aviation. Between World War II and 2008, the airport was used as a military airport. After the site was closed, it was bought in 2010 by the province of Overijssel and the municipality of Enschede. Today it is called Technology Base. It was not possible to use the airport as a commercial airport for holiday flights, but in 2015 it was decided to keep the airport open as a smaller airport for business jets, the flying and gliding club and aircraft dismantling. In 2017, Twente Airport opened as a civil airport.
In the adjacent business park, the Technology Base offers entrepreneurs space and opportunity for the development of innovations, industrial research, testing of manned and unmanned aviation systems and the establishment of companies in advanced materials & manufacturing and safety & security.
The big advantage is that the site is completely closed, you can only enter with a number plate or a QR code. “Recently, a number of students from Drone Team Twente from UT tested their drone there. It went wrong, the drone crashed on the runway. The amazing thing is that this is possible without creating unsafe situations for spectators. Air traffic reports at least 24 hours in advance, so there is plenty of time to clear the runway even after an unexpected crash. Here, literally and figuratively, there is all the room to test and experiment,” says Marieke Vizée, communications advisor at Technology Base.
Technology Base has installed three thousand solar panels on the hangars. Because the airport was part of the Royal Netherlands Air Force for many years, it has an independent energy network with a large capacity. The E-Flight Academy, where pilots learn to fly electric, recently installed a mobile charging station for a pilot. Vizée: “Electric cars can now land with us and charge quickly.”
“Recently, a number of students from Drone Team Twente from UT tested their drone. It went wrong, the drone crashed on the runway. The amazing thing is that it is possible… There is literally and figuratively all the space here to be able to test and experiment.”
Marieke Vizee, Technology Base
‘Something regularly burns here’
Space53 – the first test, training and development site for unmanned aircraft in the Netherlands – also established itself on site. The cluster of companies, authorities and knowledge institutions, of which the drone from Machinefabriek Boessenkool is also a part, often works together with the fire service.
“Twente is one of the first corps that used drones to put out a fire, like eyes in the sky. They use this extra information to make their implementation more efficient. Unfortunately, laws and regulations do not yet allow drones to fly out of sight of the pilot, but at the Technology Base experts from the fire service, Saxion University of Applied Sciences and the University of Twente are already extensively testing unmanned flight with a sniffer drone. As soon as the legislation allows it, the fire brigade can already send the drone on so that it can ‘smell’ if, for example, dangerous substances are released, without the firefighters having to be exposed to this,” explains Vizée.
The Battery Safety Lab tests batteries and battery storage systems at the Technology Base. “Energy storage is still risky and must be done very safely. That is why they are also on site with us. Here, things regularly catch fire, but we are quite used to that”, smiles Vizée.
Strong laws and regulations
But despite the fact that Twente Airport is completely closed, the H2 Big Drone project is not allowed to make test flights there with drones weighing more than 25 kilos. Osse: “If it’s not allowed there, where? You have to start somewhere and gain experience.” He sees that companies in countries with more flexible laws and regulations move much faster. “It would be such a shame if we miss the boat. Twente has all the facilities to do more test flights in any case. The only solution is more flexible laws and regulations.”
“If it is there [Twente Airport, red.] if not where? You have to start somewhere and gain experience.”
Eelco Osse, Maskinfabrik Boessenkool
Vizee agrees. “Our location is perfectly suited to this kind of experimentation and could actually contribute to a relaxation of laws and regulations. We have plenty of space to perform test flights with the H2 Big Drone. Here it can be tested under realistic conditions until it is proven that it can be flown safely. If something goes wrong in that test phase, the man is not needed. The Twente Safety Campus is located on our website. They specialize in fire safety, including when it comes to extinguishing the relatively new hydrogen.”