Nasa’s all-electric X-57 plane is preparing to fly; All you need to know

NASA's "all-electric" plane X-57 is soon set to take off, the US space agency said on Tuesday. The plane has 14 propellers along its wings and is powered entirely by electricity.

Recently, NASA's X-57 Maxwell performed successful thermal testing of its cruise motor controllers.

Thermal testing is important because it validates the design, operability, and workmanship quality of aircraft controllers. The controllers have temperature-sensitive parts and must be able to withstand extreme conditions during flight.

The X-57 uses lithium batteries to run electric motors for its propellers.

The cruise motor controllers convert the energy stored in the aircraft’s lithium-ion batteries to power the aircraft’s motors. However, the energy of lithium-ion batteries is 50 times less than aviation fuel.

The controllers use silicon carbide transistors to deliver 98% efficiency during high-power take-off and cruise, meaning they do not generate excessive heat and can be cooled off by the air flowing through the motor.

The X-57 is a modified, four-seater, Italian-built Tecnam P2006T aircraft. It relies on a combination of lots of propellers, small motors, and many batteries spread out across an aircraft, known as “distributed propulsion”, The Conversation reported.

X-57's distinctive feature is that the wings are completely redesigned with propellers positioned to optimise airflow around them. When a propeller is not needed, its blades can be folded back to reduce drag.

Propeller technology generally is having a rebirth. Designs are becoming not just more efficient, but also less noisy and more affordable. The speed and pitch angle of propellers can even be changed during flight to adapt to the different aircraft speeds required for takeoff, landing, and cruising.

Battery technology

The X-57 uses off-the-shelf lithium-ion batteries. This is because the project is primarily addressing the potential for new propeller and wing configurations rather than developing the perfect battery.

But that will be an important challenge for electric aircraft developers to overcome. Lithium batteries are one of the best substitutes to fuel, but they are still heavy. Lithium metal is also hazardous as it catches fire easily.

There are advantages to using batteries. Their weight stays constant throughout the flight, meaning they don't need to be stored in the wings as aviation fuel traditionally has been.

With liquid fuel, the weight of the plane reduces significantly as fuel is consumed, and keeping the fuel in the wings ensures that the balance of the aircraft isn’t changed.

With a range of about 160 km and a flight time of about one hour, the X-57 is not expected to lead to a replacement technology for long-haul flying. Instead, short-hop flights with ten or so passengers are a good and potentially possible target for early, battery-powered flights.