The theme of this year’s Aeronautical Society of South Africa Annual Conference was African Aerospace: Innovation and Passion and it examined local and international developments, from additive layer manufacturing, test flying the F-35 to local advances in satellite components manufacture.
The conference, held at the CSIR earlier this week, allowed for big ideas from South African industry to be put on the table. Sias Mostert, Executive Chairman of SCS Aerospace, a satellite design company based in Somerset West, proposed African countries join together to launch small satellite mini constellations. Mostert estimates that a constellation for real time coverage for communications would cost in the region of 400 million euros and a constellation for high-resolution earth observation would cost about 500 million euros.
South Africa is one of a tiny handful of countries to have launched rockets into space and developed its own satellites, with SCS Space, CubeSpace and the Cape Peninsula University of Technology (CPUT) developing (mostly small) satellites.
Another South African space company, New Space Systems, which is also based in Somerset West, presented their design for a fluid actuator to change the attitude of satellites. The fluid actuator changes the craft’s direction by pumping a dense metallic liquid contained in an enclosed ring in a particular direction. A company engineer working on the design, Rudi Glatthaar, told the conference the company plans to deliver a system within about a year. It will help lower costs, by reducing weight and space on satellites. Presently, reaction wheels, magnetic torquers, and thrusters are used to change the attitude of a satellite, in order for example to point a camera in a desired direction.
Vernon Davids, the Co-founder and CEO of startup SA space company, LambdaG, which is developing a number of sub-assemblies for satellites, gave an update on his company’s developing product range. The company uses metallic 3D printing to produce light weight parts for components and sub-assemblies.
3D printing/additive layer manufacturing was a prominent topic at this year’s conference. Niel Agenbag, Stress engineer at Denel Aerostructures, looked at metal 3D printing done by Denel Aeronautics and the Aerospace Industry Support Initiative (AISI) using a selective laser melting system from local additive layer manufacturing company Metal Heart. Their machine allows metal printing, using lasers and metal powder, up to 280x280x365 mm.
Agenbag said several specimens were printed in aluminium, in different directions/angles in order to test their properties. A total of 60 specimens were printed and results found they were on average comparable to mild steel. Some specimens weren’t good enough for aerospace applications, but others had very acceptable results.
He said that it is viable for aluminium components to be manufactured locally using selective laser melting, although some further research is necessary. Agenbag believes that 3D printing can be used as a tool for accelerating technical progress, with the technology able to liberate and democratise engineering. Some of the advantages include fast turnaround times for parts and quick feedback. He said 3D printing/additive layer manufacturing could bring as much change to the industry as the printer did to the written word.
On a similar note, Dr Louis Tredoux, Senior Expert, composites innovation and portfolio at AAT Composites, gave a case study of how 3D printing helped AAT quickly develop more cost-effective moulds. The company used to use wood and other materials to create its composite moulds, but when it switched to 3D printed moulds, this reduced lead time by 50% and significantly reduced costs. For instance, a prepreg mould would take about eight days to complete while a 3D printed mould takes only three days.
AAT designs and manufactures composite solutions, specialising in aircraft parts for the export market, including bucket seats, interiors, structural parts, as well as high-end automotive work. The Cape Town-based company was established locally but was subsequently bought out by Germany’s Recaro Aircraft Seating. ATT Composites has 550 employees and has the capacity for 3 000 mouldings per week using 2 000 kg of materials.
Speaking on the innovation and passion theme of the conference, Major Nandi Zama, the South African Air Force’s first black woman C-130 Hercules transport aircraft Commander, argued that change of various types could be a source of innovation, with a re-alignment in thinking. Apart from her role in the Air Force, Zama is actively involved in encouraging young girls to take up science and maths subjects and fly.
Chief Test Pilots from Lockheed Martin and Boeing gave keynote addresses on the first day of the conference on 15 October and also touched on innovation and technical progress. Billie Flynn, the Senior F-35 Test Pilot at Lockheed Martin, described how in the face of much public scepticism about the cost and capabilities of the most advanced and costly fighter project ever, as well as setbacks, credibility had been restored. Mitigating risks in flying the aircraft, through hours of work on a simulator to establish the best routines in the event of multiple failures and the use of experienced “Mother Hens” for pilot guidance was key to establishing safety and changing the critical conversation about the plane, he said.
Among the key capabilities that make the F-35 a game changer is “sensor fusion” and stealth, according to Flynn. The ability of the F-35 to integrate into a wider network of fighters and draw information from a range of sources as well as its stealth has meant a fundamental change in fighter aircraft procedures. Sensor fusion has reduced the pilot workload and allowed far better focus on threats.
The extensive use of algorithms for the operation of the F-35 has meant that older and more experienced pilots have had to adapt to a very different environment. Youngsters with a little over 100 hours in flying time have often showed themselves to be more capable F-35 pilots because of their ability to adapt and their deep familiarity with screen-based systems. Younger pilots are now demanding more information and more screens, he said.
The new technology has also brought about changes in the command structure in the air. Due to messaging with visual representation on screens and helmet displays, there is little use of radio, and pilots are afforded far greater independence and decision-making in the air.
In another keynote address, Ricardo Traven, Boeing’s Chief Test Pilot for the 787 Dreamliner Programme, swept through aeroplane design history from a Darwinian evolutionary perspective in trying to answer the question of what makes for the survival or extinction of a design. The C-47 Dakota, used as a military transport during World War II, remains in use in South Africa to this day, and the US Air Force’s B-52 Stratofortress bomber, with an average age of close to 60, remains in service. The C-130 Hercules transport is another example of long survival, due to performance and the right characteristics. All these indicate the key to survival is a “balanced design” which can flourish in changed environments, according to Traven.
Traven said it was difficult to make design decisions that would ensure survival, but the best advice was to repeat that given by a US Admiral on what he required for an unmanned aerial vehicle that could deploy from ships. The Admiral said he wanted an “airframe and lots of USB ports” for updates.
But is there an optimal design for aviation structures? This was an issue tackled by University of Pretoria Mechanical and Aeronautical Engineering Faculty member, Joachim Huyssen in his conference address. Results from his study on “Testing the Natural Dominant Configuration for Aviation,” show this to look somewhat like an Albatross.