Silent, Solid-State Propulsion for Advanced Air Mobility Vehicles

Graphic depiction of Silent, Solid-State Propulsion for Advanced Air Mobility Vehicles. (Credits: Steven Barrett)

by Douglas Messier
Managing Editor

NASA is funding research into how to reduce noise levels produced by the next generation of vertical takeoff and landing (VTOL) air mobility vehicles.

The space agency is providing Steve Barrett of the Massachusetts Institute of Technology with a NASA Innovative Advance Concepts (NIAC) Phase I grant worth $175,000 to develop an electroaerodynamic (EAD) propulsion systems that would allow VTOL vehicles to fly much quieter.

“EAD produces thrust through collisional ion acceleration without any moving surfaces. As such, EAD thrusters are nearly silent, enabling missions that would not otherwise be possible due to community opposition to noise,” the proposal abstract said.

“Example missions enabled by silent EAD propulsion include those near noise-sensitive urban communities, or time-critical delivery missions at night (e.g. for critical medical supplies), when community opposition to noise is most severe. Novel multi-stage ducted (MSD) EAD thrusters, in which multiple EAD thruster stages are enclosed inside a duct, will be used to increase thrust enough to enable VTOL operations,” the document added.

The project abstract follows.

Silent, Solid-State Propulsion for Advanced Air Mobility Vehicles
Steven Barrett
Massachusetts Institute of Technology
NIAC Phase I
Amount: $175,000
Length: 9 months

Advanced air mobility (AAM) is an aviation ecosystem that envisions small, electric, vertical takeoff and landing (VTOL) aircraft operations in urban areas. Community opposition to noise is likely the biggest obstacle to the widespread adoption of AAM vehicles.

We propose to overcome this obstacle via designing electroaerodynamic (EAD) propulsion systems for AAM applications. EAD produces thrust through collisional ion acceleration without any moving surfaces. As such, EAD thrusters are nearly silent, enabling missions that would not otherwise be possible due to community opposition to noise.

Example missions enabled by silent EAD propulsion include those near noise-sensitive urban communities, or time-critical delivery missions at night (e.g. for critical medical supplies), when community opposition to noise is most severe. Novel multi-stage ducted (MSD) EAD thrusters, in which multiple EAD thruster stages are enclosed inside a duct, will be used to increase thrust enough to enable VTOL operations.

Under this effort, we will design a VTOL-capable, near-silent aircraft powered by MSD thrusters. The aircraft would enable package delivery missions in noise-sensitive areas or at night, where operations would otherwise not be allowed due to community opposition. This effort would be in support of the long term goals (1) to build and fly an MSD-powered aircraft, and (2) to assess the applicability of MSD thruster technology to other AAM use cases, including intra- and inter-city passenger transport.