At Farnborough Airshow, EADS Innovation Works presented the prototype of a portable Unmanned Aerial Vehicle (UAV) produced by Additive Layer Manufacturing (ALM) technology, also known as 3D-printing. The plane with a wingspan of approximately 1.5 meters has been designed by students from the University of Leeds. The small, portable drone will be capable of being controlled via wireless video communication over a short distance. Powered by batteries, it could serve as a tool for surveillance, search and rescue or disaster control.
Using ALM technology in the production of such a small drone opens new possibilities for aerodynamic optimizations such as wing twist, which would otherwise be difficult and expensive to realize for an aircraft of this scale. Different, detachable wings can be “printed” in a relatively short time to adapt the UAV to missions with different requirements.
The four students from the University of Leeds’ Faculty of Engineering have developed an initial concept of the UAV, created the design and performed an aerodynamic analysis under the supervision of EADS expert Martin Muir. In order to take advantage of the ALM technology the students carried out a detailed design of the wing through topology and aerodynamic optimisation. This allows building a pair of wings which are optimised in terms of weight, aerodynamics and stability and yet cheap to produce. Thanks to the tests performed, both the angle of incidence and the angle of twist could be optimized. Normally, manufacturing of such complex parts would be too expensive for a small UAV. With ALM, it is possible to produce several sets of – for example – wings tailor made for different missions at a reasonable price.
The students also performed a stability and control analysis of the whole system and produced assembly instructions for the print shop. A flight capable metallic version will be manufactured at EADS Innovation Works UK ALM facilities in Filton. This plane will be produced using innovative Direct Metal Laser Sintering (DMLS) technology. The plastic material UAV shown at Farnborough serves only for exhibition purposes and displays the design features made possible by ALM technology.
The UAV has been sized to take advantage of future propulsion systems, such as the Lightweight Hydrogen Fuel Cells (LwHFC) currently under development by EADS Innovation Works. A replacement of the existing battery system with the LwHFC would increase the endurance of the UAV from two hours of continuous flight, to approximately six hours. The sizing and optimisation of the UAV’s fuselage and wings was undertaken with the future use of LwHFCs in mind, hence the large open spaces and large profile wing.
The revolutionary manufacturing process known as Additive Layer Manufacturing (ALM) is based upon the principles of rapid prototyping and allows single products to be grown from a fine powder of metal (such as titanium, stainless steel or aluminium), nylon or carbon-reinforced plastics. EADS has developed the technology to the extent that it can manipulate metals, nylon, and carbon-reinforced plastics at a molecular level, which allows it to be applied to high-stress, safety critical aviation uses. Compared to a traditional, machined part, those produced by ALM are up to 65% lighter but still as strong as those would be. Simply put, a part is designed on a computer, which then directs a high-powered laser at material in powder form, melting it into a solid shape, repetitively, layer by layer, until the desired part is completed. The development of ALM is an activity that spans the entire EADS group, with early applications in the production of fixtures and tooling for Airbus, and flying applications being implemented by Eurocopter and Astrium. EADS’ UK research facilities have the lead in the group’s ALM activities.
Another piece of innovative ALM technology made in UK on display at the EADS’ stand is the Laminar Flow Device which can be mounted on the leading edge of an aircraft’s wing section. It enables laminar flow over large portions of a swept wing by removing the turbulent boundary layer of the attachment-line flow at the wing’s leading edge. Laminar flow causes less skin friction drag than turbulent flow and therefore helps to reduce fuel consumption.
ALM technology makes it possible to produce the complex contoured shape at a low cost. The device on the model on display at Farnborough is produced using the EADS proprietary ScalmalloyRP material, which provides exceptional mechanical properties useful in the production of complexly shaped structures.