More Electric Aircrafts

I am writing this post from the studies I am doing these days on Actuator Technologies, part of TSG group for the company I am working with.

For years engineers have dreamed of an all-electric aircraft. They have envisioned a concept called "Fly-by-wire," in which electrical power moves aircraft flight surfaces. Gone would be the complex, heavy, maintenance-intensive, and (in combat) vulnerable hydraulic systems with their flammable liquids operating at high temperature and pressure. Gone, too, would be the miles of tubing, the pumps and valves. Weight could be shifted from plumbing to passengers, fuel or mission payloads.

The transition to an all-electric aircraft is still many years in the future. But aircraft engineers have tested electrohydrostatic actuators (EHAs), which combine electrical and hydraulic power. Hence the evolutionary "more electric aircraft" idea. EHAs are electrically powered but use small hydraulic pumps and reservoirs that transform electrical power into hydraulic power.

To move the huge Primary and Secondary surfaces of the aircraft hydraulically, only, was considered but was discarded in favor of a hydraulic-plus-electric flight control architecture in the past.

The use of electrically powered actuators, however, allows designers to efficiently segregate power distribution channels and save weight. Increased hydraulic pressure in the remaining hydraulic circuits–from 3,000 psi to 5,000 psi–also saves weight. It reduces the size of components, generation equipment, tubing, and the amount of fluid required, and makes installation easier. Overall, the benefits are clear: improved reliability and maintainability; reduced weight and increased cost savings; and increased safety margin because of the use of dissimilar power sources. "Because of the dissimilar [flight control] architecture, if we lose hydraulic power, the aircraft does not lose any flight handling capabilities. "There will be no impact on the performance of the aircraft."

Electrohydrostatic actuation will generate large weight savings. "The combination of the higher hydraulic pressure and the ‘more electric’ flight control architecture led to a weight reduction of approximately [3,307.5 pounds] 1,500 kg for the aircraft. For variable-frequency power generation, "weight was not the driver". That decision "was more oriented to reliability and maintenance cost." "It’s clear that we are oriented more and more toward the ‘more electric aircraft,’" these days.

More to follow soon. Stay Tuned!