“E-Flying”: quieter, greener planes with electric drives
The NASA engineers plan to devise a nine-passenger plane with a 500-kilowatt power system ready for flight by 2019. Even before this date, the researchers intend to take off with an experimental electric plane, called Sceptor. The acronym stands for Scalable Convergent Electric Propulsion Technology and Operations Research and is based about a small conventional P2006T plane from Italian manufacturer S.R.L. Costruzioni Aeronatiche Tecnam, modified for electric propulsion. The design modifications focus on the wing that will replaced by a completely newly designed wing with 18 (yes, eighteen) albeit rather small propellers.
This idea goes back to NASA’s Leading Edge Asynchronous Propeller Technology (Leaptech) research activities started in 2015. The experimental carbon composite airfoil integrates 18 electric motors that drive the same amount of propellers. The energy is stored in lithium iron phosphate batteries.
Tests so far have shown that the distribution of thrust among the 18 motors creates more than twice the lift at low airspeeds compared to conventional systems, said Sean Clarke, Sceptor co-principal investigator at NASA’s Armstrong Flight Research Center at Edwards Air Force Base in California.
The R&D works include testing the experimental wing on a truck as well as developing a simulator to investigate control and handling characteristics of an electric airplane and the related verifying tools.
The experimental wing, called Hybrid Electric Integrated Systems Testbed (HEIST), will initially be mounted on a modified truck and is used for a series of research projects intended to integrate complex electric propulsion systems. The testbed functions like a wind tunnel on the ground, accelerating to as much as 73 mph (118 kmph) to gather data. Researchers have used the testbed to measure lift, drag, pitching moment and rolling moment that can validate research tools.
Other R&D activities include integrating the Sceptor aircraft systems with a flight simulator for pilots to evaluate the handling properties. The researchers will also be able to study balancing the power demands of the motors with batteries and then a turbine, because they are interested in learning if a hybrid of distributed electric motors and gas-powered turbines could provide power to extend the aircraft’s range.