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| Bennie Broughton |
Dr Bennie Broughton (33), a CSIR principal researcher and expert in aerodynamics and flight dynamics, works on challenges mainly associated with combat situations in hostile territories. The potential uses of unmanned aerial vehicles (UAVs) in this context, but also a myriad of civilian applications, are the rationale for investment in this research.
Challenges associated with combat situations in hostile territories range from the fear of being trapped in an ambush situation in a well-defended battle field and the threat of ground-to-air missiles that can destroy a fighter plane and fatally wound the pilot, to border and maritime patrolling and general crime-combating duties. All of these elements are linked to the development of unmanned aerial vehicles (UAVs) at the CSIR.
The CSIR's research into UAVs started in the early 1980s with what was then known as remotely-piloted vehicles (RPVs), and at the time mostly limited to military applications. The new generation UAVs has revolutionised this technology.
A UAV is an unmanned aircraft that can be operated via remote control or flown completely autonomously, based on pre-programmed flight plans or more complex dynamic scenarios. These are currently used in a number of military roles, including visual reconnaissance and other forms of aerial data collection, as well as for commercial and scientific purposes. Some countries are even using UAVs as offensive weapons, usually referred to as unmanned combat air vehicles.
UAVs are also used in a small but growing number of civil applications, police observation of civil disturbances and crime scenes, reconnaissance support in natural disasters, powerline and oil pipe inspections, border patrol and game counting. UAVs are often preferred for missions that are regarded as too 'dull, dirty, or dangerous' for manned aircraft.
Modern UAVs are equipped with an autopilot handling most of the aspects of the flight that allows the operator to either pre-program the route to follow, while he/she can still change the mission or waypoints once the UAV is in the air. This high level of automation, according to Broughton, is a major improvement over first generation RPVs.
Broughton says that anyone, including soldiers and police personnel on the ground, can operate the new generation UAVs. In the past operators were required to undergo training similar to that required of pilot-manned aircraft – automation has changed this expensive requirement.
These many potential applications for UAVs are what motivate researchers working on the challenge of keeping them in the air long enough to be useful.
“We also face other challenges: Making them more user-friendly, so that we don’t need specially-trained pilots, and ensuring the safe integration of UAVs into civilian airspace without them becoming a danger to manned aircraft.”
Designing UAVs to fly for longer distances and, more importantly, longer durations by building more efficient, low-drag airframes and developing better propulsion methods are other technical hurdles that Broughton and his team are hoping to conquer.
“About three years ago we designed a UAV called Indiza,” says Broughton. “This UAV used a very conventional aerodynamic configuration and was meant to demonstrate some of our capabilities, while it would serve as a vehicle to test some of the new technologies that we are working on.”
With that project being implemented, researchers decided they wanted to look at more advanced design and control methodologies and project Sekwa (which means 'duck' in Tsonga) was launched.
This UAV is one of the most sophisticated ever produced by the CSIR, despite its small physical size – it is a blended wing body with the fuselage part flowing into the wing. “One of the things researchers tried to do was to push this UAV to the limits in terms of efficiency.”
“We did this in part,” says Bennie, “by decreasing the natural stability of the UAV – usually aeroplanes need to be naturally stable for a human pilot to control it properly - but we decided to disregard some of the stability requirements to research the advantages this may hold for improved aerodynamic efficiency. This required the use of a very sophisticated control system to compensate for that instability. We have been working in partnership with the Stellenbosch University on the development of the control system, while we were making use of mathematical optimisation to define the optimal aerodynamic shape of the UAV,” he says.
At this stage Sekwa is ready for its first automated test flight. Researchers have already flown it in a stable configuration via a conventional radio control system to verify its overall performance and whether manual recovery of the UAV would be possible if the control system ever failed during the more advanced testing. The design allows them to adjust the level of stability or instability during flight, and any failure of the control system will automatically revert it to a stable configuration. The next test is to fly it with the control system active and the centre of mass pushed back so that it becomes unstable, which should lead to small but significant improvements in aerodynamic efficiency.
But the demand for UAVs is huge. Many military teams in the first world already deploy UAVs for all its platoons. African and other third world countries torn by conflict are following suit and applying this technology for peace-keeping missions. “There are many designs out there and this is where it is important to make sure you are more efficient than other players,” says Broughton, who also reveals that CSIR researchers aim to maintain their position at the forefront of UAV technology.
“We need to make sure that we are up there with the best and that our technology remains cutting edge.”
This is exactly what the man, who played a key role in the acceptance of the Gripen fighter aircraft into service in the South African Air Force (SAAF), has set himself out to achieve.
Broughton was an undergraduate CSIR bursar and did his first vacation work at the organisation in 1993. He graduated with BEng and MEng degrees in mechanical engineering from the University of Pretoria and a PhD in aerospace engineering from the University of Illinois in the United States.
He has also completed the SAAF's operational test and evaluation course. He has spent about half his time since joining the CSIR, on UAVs, and the remainder helping the SAAF with the evaluation of flying qualities of fighter aircraft.
“Here I get to work with the newest toys of the Air Force and I have even had a few rides in the back seat of one of its Cheetahs! Who can ask for more variety?” he quips.
Broughton says he does not experience one minute of boredom, except maybe when he has to write the occasional report, but it is all part of the fun.
How did he decide on becoming an engineer? “I built model aeroplanes since the age of about six and started flying and later designing my own radio-controlled models in high school,” he says. “The only other career I ever considered was to be a pilot, but I am very happy about how things worked out.”
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