MILITARY, AEROSPACE & DEFENCE INDUSTRY FOCUS


The traditional fleet of airliners and business jets is set to be joined by electric vertical take-off and landing (eVTOL) taxis, and the next generation of supersonic aircraft. What they all have in common is a


requirement for high-performance precision motors. Julian Del Campo, senior industry manager at Portescap, looks into the solutions


SPECIFYING MOTORS FOR AEROSPACE APPLICATIONS


n the aerospace industry, there are multiple design considerations when it comes to selecting motion control solutions for use outside the cabin. For a start, during take-off, flight and landing, commercial aircraft must contend with shocks and vibrations, yet every system and its subcomponents must meet long- term reliability requirements. To meet demands, the motors can be reinforced, with potting for slotted designs or by using advanced laser welding when assembling components. Additionally, a commercial aircraft will


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repeatedly face temperatures ranging from -55˚C to 125˚C. Here, motor designers can ensure reliable operation by tailoring electric current to provide similar operation across this entire temperature range. Specifying custom bearings with low outgassing and extreme temperature lubrication helps ensure consistent performance. As an aircraft repeatedly travels up to 30,000 ft. and back down, the repeated temperature cycles can cause moisture to build up on surfaces, raising the risk of oxidation and damaged electrical components. However, by choosing corrosion resistant materials for metallic parts and applying special printed circuit board (PCB) coatings that combat corrosion and resist absorption, this can be mitigated.


MOTOR APPLICATIONS On aircraft, propulsion systems generate the power to propel planes through the atmosphere, while fuel systems manage the efficient delivery of kerosine to power the engines. Both are essential for enhancing performance, range and reliability. Motors are used to operate fuel valves outside the cabin, and with extreme temperatures and vibrations present, a robust design is essential. Power and torque density are critical, as performance must be balanced with space and weight savings to improve the characteristics of the aircraft. Consequently, BLDC slotted and slotless


motors are preferred. These are also highly customisable, allowing them to perform in a wide range of operations. Furthermore, flight control systems allow


aircraft to safely maintain stability and manoeuvrability in the air. Sensors, computers and actuators allow highly accurate piloting and command of flight parameters like altitude, heading, and attitude. Multi-facetted systems are designed to reduce human workload while improving efficiency and safety, with side sticks, yokes, autopilot actuators and flight control surfaces working in harmony. From pilot controls to smart trim actuators,


precision motors are utilised across flight control systems. All must quickly and precisely respond to inputs from the pilot or sensors, especially when paired with feedback devices like encoders and resolvers. For use outside the cabin, temperature and vibration resistance must be built in. The variance in possible applications means a myriad of possible solutions, from complex flat motor systems with redundancies for autopilot systems, to commercial-off-the- shelf (COTS) designs for side stick feedback.


CABIN COMFORT Environmental control systems are crucial for the comfort of the passengers and the crew. While cruising in the jet stream, these systems manage temperature, humidity, and pressure in the cabin. Motors used here need to be power and torque- dense, suiting the characteristics of BLDC designs. Efficiency is also key as, after clicking in their seatbelt, passengers usually turn their attention to air vents. Frequent usage of the valves in the HVAC system can be balanced out by a motor that reduces power drain on the overall system. Though located inside the aircraft, these motors often encounter refrigerants and other caustic substances, so some form of protection and robust system design are required. With the precision needed to regulate


conditions in the cabin, stepper motors are often


used here. Whether operating as standalone or in a complete motion system with custom housings and integrated geartrains for an easily installed assembly – both must be suitably modified to application requirements. Miniature precision motors are also seeing


increased use in window shades and seat actuation applications. Beyond the advantages of small size and reduced weight, key things to consider include smooth and quiet operation. Furthermore, ensuring that motors produce low electromagnetic interference (EMI) helps safeguard the operation of key systems on the aircraft. Ultimately, DC motors are ideal for both


applications. Quiet, efficient and power-dense, these meet the criteria for use inside the cabin. Motors can be incorporated with gearboxes and encoders as a complete motion system, while EMI protection and thermal fuses help safeguard system performance and reliability.


MEETING INDUSTRY STANDARDS Two industry standards support the design methodologies required to supply to aerospace: RTCA DO-160G ensures that all devices used


on aircraft can withstand the harsh environmental conditions during operation, encompassing temperature, shock and vibration. Brushless DC (BLDC) and DC motors can be designed to meet these criteria, as well as varied customer performance requirements.


Another is AS9100 – a set of guidelines that aerospace suppliers must meet to ensure the quality and safety of their products and services. Attaining this standard means manufacturing motion solutions in a highly controlled manner within a rigorous quality management system, resulting in extremely proficient products. Portescap’s Mumbai, India, facility attained AS9100 certification in 2023.


Portescap www.portescap.com


FEBRUARY 2025 DESIGN SOLUTIONS 49


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