Tech Briefs Magazine - August 2022 - 32

Aeronautics
Fixed-Wing Angle eVTOL
New design removes the need for mechanisms to perform active tilting of the wings or
rotors, reducing system mass.
Langley Research Center, Hampton, VA
C
urrent electric vertical takeoff and
landing aircraft (eVTOL) configurations
for Urban Air Mobility (UAM)
applications often require performance-hindering
equipment only used
for a specific operation (e.g., takeoff or
cruising). The need for such equipment,
such as separate lift and thrust mechanisms,
often stems from the challenge
posed by transitioning from hovering
to forward flight. For example, tilt-wing
eVTOLs have complex transition periods
that can result in large pitching
movements or wing stalling without adequate
propulsion, potentially causing
catastrophic loss of control.
Increased equipment requirements
for eVTOLs also increase system mass,
negatively impacting performance. Innovators
at NASA's Langley Research
Center recognized this issue and have
developed a novel eVTOL solution design.
The technology is a distributed
electric propulsion, modular wing aircraft
capable of vertical takeoff and landing,
without requiring near 90° wing tilt.
Instead, NASA's eVTOL uses large flaps
and a fixed slight wing tilt to generate
upward force, enabling VTOL operations,
benign transition from hovering
to forward flight, and increased safety
and simplicity of operations.
NASA's design instead uses a slight
Image Credit: NASA
NASA's eVTOL uses large flaps and a fixed slight wing tilt to generate upward force. (Image: NASA)
wing angle and large flaps designed
to deflect slipstream generated by
the propellers to create a net positive
force in the vertical direction, all while
preventing forward movement. This
unique configuration allows for takeoff
and landing operations without
the need for near 90° wing tilt angles.
After takeoff, the transition to forward
flight only requires a slight change in
attitude of the vehicle and retraction
of the flaps. Similar solutions require
large changes in attitude to accomplish
this transition, which is often undesirable,
especially for air taxi operations
that involve passengers. Given the effectiveness
of this configuration for
generating upward force, the requirement
for wing angle tilt has been reduced
from near 90° to approximately
15° during takeoff.
Further iterations may reduce this requirement
even further to 0°. By eliminating
the need for near 90° wing tilt,
NASA's eVTOL design removes the need
for mechanisms to perform active tilting
of the wings or rotors, reducing system
mass, and thereby, improving performance.
Flaps represent the only components
that require actuation for takeoff
and landing operations.
NASA's LA-8 UAM testbed vehicle used to design and test this unique configuration. (Image: NASA)
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32
Innovators at NASA leveraged the
Langley Aerodrome 8 (LA-8), a modular
testbed vehicle that allows for rapid
prototyping and testing of eVTOLs, to
design and test this novel concept.
NASA is actively seeking licensees to
commercialize this technology. Please
contact NASA's Licensing Concierge at
Agency-Patent-Licensing@mail.nasa.gov
or call at 202-358-7432 to initiate licensing
discussions. For more information,
visit https://technology.nasa.gov/patent/
LAR-TOPS-338.
Tech Briefs, August 2022

https://technology.nasa.gov/patent/LAR-TOPS-338 http://www.techbriefs.com

Tech Briefs Magazine - August 2022

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