As the US military recognises the advantages of flapping-wing technology, the man who has achieved in 30 years what Leonardo da Vinci failed to do in a lifetime talks to Rob Coppinger.
Leonardo da Vinci could only dream of flight using mechanical flapping wings, but James De Laurier has spent much of his engineering career making it a reality.
Bird-like aircraft, known as ornithopters, proved a dead-end for many pioneering aviation engineers of the late 19th century, but 100 years later flapping wing-powered robots are potentially the US military’s latest toy.De Laurier, a professor at the University of Toronto’s Institute for Aerospace Studies, can take much of the credit for making that possible and now sees a decades-long engineering obsession bearing fruit.
The amiable Canadian-American finds himself involved with some of the US defence establishment’s most cutting-edge research, while his university team has built a person-carrying ornithopter that ’hopped’ into the record books in 1999.
De Laurier started his endeavour to make da Vinci’s dream a reality in the early 1970s when fellow engineer Jeremy Harris, with whom he worked at Ohio’s Battelle Memorial Institute, introduced him to what was, by any standards, an obscure backwater of aeronautical engineering.
’The ornithopter was kind of a hobby at first,’ said De Laurier. ’It was what me and Jerry did to have fun – some guys go bowling, but we were a couple of nerd engineers that just worked on the problem of mechanical flapping winged flight. We didn’t know we were beginning a path that would lead us through two decades.’
With only rough ideas about how ornithopters could work, De Laurier and Harris set out believing they could solve the problems of flapping wing propulsion in a few years. Thirty years later there are still obstacles to overcome.
’We didn’t think it would take this long when we started, or that it would be a major part of my career. We thought we’d knock it off pretty quick,’ said De Laurier.
In fact, it turned out to be a formidable challenge, requiring the development of sophisticated computer code, systematic wind tunnel testing and structures analysis. A lot of this research formed the basis of De Laurier’s postgraduate students’ theses. This combination of ’tinkering’ and real research over 20 years eventually got the pair to the stage of a remote-controlled ornithopter.
’What we achieved in 1991 was the world’s first successful engine-powered, remote-controlled model. It had a 10ft wing span and was essentially a technology demonstrator for the full-size ornithopter.’
Eventually the designs had to be turned into actual machines, which took cash. While funding the model presented no problems, the full-size ornithopter was to prove a tougher prospect altogether.
Harris invested a substantial sum of his own money, while the Canadian government provided matching grants. Other donations included parts and materials, and the project also benefited from an annual grant of $20,000 (£12,000) from the Kenneth Mulson Foundation, which supports aviation.De Laurier appreciates the time and money that so many others have put into helping his dream become a reality.
’It’s really nice, but I’ve worked in industry and if this was an industrial project we’d be talking millions. The donations mainly paid for the materials and the ground crew, students and their theses are paid for by scholarships.
’What made this project possible is the fact that I am doing it in a university environment and I have student volunteers. But make no mistake, this has been run on an under-funded shoestring budget. That is why it has taken so long.’
With a final design completed in 1995 the full-scale ornithopter was built in the following year and began taxi trials that year prior to its first ’flight’ in 1999. If the aircraft itself seems bizarre, the story of its first pilot is equally so. UK-born Patricia Bowman-Jones was an amateur with an instructors rating. De Laurier explained the strange turn of events: ’She contacted us through her dentist. He had helped us build some jigs for the wing spars and happened to mention the project while she was having treatment.’
De Laurier would have been happy if the whole ornithopter project had no practical applications. In his view, it was simply curiosity-driven research, which he feels is no bad thing. For him history is littered with productive research that was originally curiosity driven.
In the case of the ornithopter project, spin-offs include potential solutions for aircraft roll control. This has led to the US government’s Defence Advanced Research Projects Agency (DARPA) getting involved with the initiative on morphing wings for aircraft.
And while the fixed-wing model will prevail for the foreseeable future for full-scale aircraft, the ornithopter has interesting potential for smaller, bird-size craft. In recent years micro aerial vehicle (MAV) projects have gained substantial research funding.
De Laurier explained: ’Since the beginning of the 1990s everyone has been starting to look at the utility of flapping wings for micro aerial vehicles.
’It’s interesting because the whole world, at least the research world, seems to be interested in flapping flight. But at the time we were working on it we were all alone – us and a few nutcases.’
According to De Laurier a mechanical insect or bird-like aircraft has very real advantages. At low speeds and at very small scale, traditional aerodynamics become very inefficient. This is where flapping machines become useful.
’With flapping wings you do things to the air, in the way of vortex generation and interaction, that can enhance your aerodynamic efficiency and enhance how much force you can generate.’
These vortices can come from the ’clap wing’ phenomenon. This is where wings flap to such a degree that they meet at the top and the bottom of the wing stroke, generating a lot of lift. It is how birds take off and explains why the full-size ornithopter only ’hopped’. It could not replicate ’clap wing’.However, the effect is successfully being replicated for flapping wing MAVs.
While other researchers around the world work on this problem, DeLaurier has already notched up a first. His Mentor ornithopter, developed with support from DARPA, is the only one to have achieved sustained hovering. It is also able to go into a damaged building, or area dangerous for humans, and when necessary make the transition to efficient high-speed flight.
Nature’s flapping wings come in many shapes and sizes, and engineers are learning from them all. De Laurier even has a favourite: ’My dream flapping-wing aircraft is the dragonfly. Those things are just so amazing, how they can hover precisely yet can execute high-speed flight – incredible manoeuvrability.’
And De Laurier may have more time to work on such a vehicle. Though he is 62, and facing enforced retirement at 65, the Ontario government is now thinking of repealing its mandatory retirement law.
Whether or not he remains at the Institute, De Laurier can only chuckle about the outcome of his life’s hobby: ’With this resurgence of interest I’m kind of like the father of flapping-wing technology, which I find hilarious. But people are referencing my early work and I feel very gratified by that.’