It was a common love of flying that led to Barbara Barbieri and Joachim Huyssen meeting and falling in love. And it is this passion that led to the couple, now Dr and Dr Huyssen, each graduating with PhDs in Aeronautical Engineering from the University of Pretoria (UP).

But that’s the beginning and end of any similarity between them. Barbara convulsed with laughter at the mere thought of their being alike. “I am Italian; he’s German,” she says in her heavily accented English, as if that explains it all.

Her German-South African husband concurs. “We only agree that we have to complement each other on all our differences,” Joachim says.

“I think we just love adventure,” Barbara adds. “That is the only thing that unites us; otherwise, we are completely different.”

They met 23 years ago at an Aeronautical Society event at a missile test facility in Cape Agulhas in the Western Cape. It was during the last few weeks of Barbara’s five-month stay in South Africa. She was here to do research at the Council for Scientific and Industrial Research’s wind tunnel facilities for her master’s in Aeronautical Engineering, which she was doing through Italy’s University of Pisa.

Barbara was desperate to visit Victoria Falls in Zimbabwe on her last weekend in Southern Africa, and it was Joachim who flew her there. That cemented their relationship. She just loved “the crazy pilot” who “likes risk and is always on the edge”, she recalls.

Today, the parents of a 15-year-old son, the Huyssens both lecture in UP’s Aeronautical Group, a postgraduate specialisation that falls under South Africa’s largest Department of Mechanical & Aeronautical Engineering, one of 14 departments in UP’s Faculty of Engineering, Built Environment and Information Technology.

Despite teaching in the same discipline, their interest in aeronautics, the science of aircraft and flight comes from different perspectives. For Barbara, flying represents freedom. It’s about the magic of seeing reality from above which, even without the small details, means “you can see another view of the world”, she says. For Joachim, it’s all about the physical challenges of flying.

“As a keen observer of what’s going on in nature, I was always fascinated by the flight of birds and the differences to human flight,” he says. Both can travel through what he terms “the ocean of air that connects all places on earth”, but humans are “bound to runways and ground infrastructure”. “I needed to understand the differences in design, and that became the core of my PhD,” Joachim says.

Today his illustrations in academic articles about reconfiguring the shape of aircraft resemble the shapes found in nature. It was already the subject of his master’s at UP, which he obtained cum laude and for which he designed a full-scale tailless aircraft. Later, it became the testbed for his PhD titled ‘The existence of a family of ideal aircraft configurations’, supervised by Professor Geoff Spedding of the University of Southern California (USC).

It has been a long journey. Construction of the full-scale aircraft began in 1994, after Joachim’s master’s, and experiments were well under way – until what he terms “the destruction”. Describing it as a “publicity stunt for funding”, Joachim needed to show the prototype aircraft in real flight. It was dropped from a hot air balloon at 2 500m above the ground, but it crashed and ended up with a broken wing.

As the test pilot, Joachim was not injured physically, but he says the accident “destroyed the experimental set-up needed for the PhD”. He was out of funding and had to let his team members go. He resumed his PhD as a part-time candidate only in 2015.

That was also when Barbara started hers, which took a very different path. “My passion is teaching and engaging with students – that gives me a lot of satisfaction,” she says. Her PhD involved “experimental research into endwall film cooling in a linear cascade of filleted veins”. The endwall is the surface holding the blades of an aircraft’s turbine engine and her research, supervised by Dr Gazi Mahmood, looked at how to optimise the cooling of these blades, taking into account the distribution, size and shape of the cooling holes on the surface.

The Huyssens continue setting new goals; their doctorates are just one step in the type of challenges they thrive on, like the time they walked to the base of K2 in the Himalayas, the second-highest mountain on earth after Everest.

They would also like to establish a research fund of R5 million. Joachim will manage the technical aspects of the research, which will involve developing the technology for the gull-configuration aircraft, for which UP has registered a patent in Europe, the US, China and Canada. Barbara will focus on student development; she wishes to enable more aeronautical students to study full-time. This research will build on their international collaboration with USC.

But first it’s time for a party.

Unbeknown to Joachim, Barbara has invited 60 colleagues and friends to their home to thank them for their support and to celebrate their achievements. And the menu? Home-cooked Italian food, “of course”, she says, because this aeronautical engineer not only boasts a PhD, but is also a brilliant ambassador for the culinary delights of the country of her birth.