Story ID: 041
Nexus eVTOL Progressing at Textron eAviation
By: Matt Thurber
Caption: Four-passenger aircraft could enter service in the 2030s
Word Count: 2137
In a building called the Glass House next to McConnell Air Force Base in Wichita, Textron’s eAviation division is forging ahead with construction of the first Nexus eVTOL aircraft. The 35-foot-long backbone of the wing—one of the largest composite parts the company has ever made—is being assembled on a jig and the fuselage unveiled earlier this year is taking further shape although separately from the wing.
Textron eAviation is leveraging the skills of experts at its sister companies to build not only the first Nexus but also the infrastructure needed to support the program. This includes Textron Aviation and its McCauley Propeller subsidiary, as well as parent Textron’s Bell and eAviation’s Pipistrel division, along with various internal resources and machinery. For example, the autoclave in which the airframe’s composite parts are cured was originally installed for the Beech Starship airframe and Premier 1/1A and Hawker 4000 composite fuselages.
Pipistrel is contributing batteries, battery management systems, and charging technology that will use the CCS1 (Combined Charging System 1) protocol for the U.S. and CCS2 in Europe. 
The program is also tapping Bell’s expertise in tiltrotor design and fly-by-wire flight controls. Now Nexus is bringing all these together to create an electric flying machine that could pave the way to an era of sustainable flight.
It is only when seeing the hardware that one appreciates how big the Nexus is; its footprint extends to about 50 feet fore and aft and side to side. This is no small lightweight aircraft, and it will take a considerable amount of power to loft it vertically into the air—namely 2,000 pounds of liquid-cooled batteries mounted inside the wings. (The Pipistrel Velis Electro uses liquid cooling for its in-house-developed battery system.)
These batteries will power four forward-tilting motors fitted with McCauley four-blade propellers—one on each wingtip as well as two tilting motors mounted on the forward end of a boom on either side of the cabin. Two other electric propulsion units oriented for lift balance out the back of each boom, and these aft proprotors are Bell designs, for a total of six propulsion units.
Each McCauley propeller is about 12 feet in diameter, the largest ever built by the company and the same diameter as the Bell proprotors. The booms are joined in the rear by the V-shaped empennage, which is designed to minimize vibration, according to JD Terry, Textron eAviation's director of engineering.
While the fuselage employs carbon fiber as a composite outer skin, some aluminum bulkheads are used where appropriate. Textron eAviation isn’t using the fiber-placement machines that wound material onto a metal form to manufacture Premier and Hawker 4000 composite fuselages.
The wing is all-composite and will extend to about 50 feet once the tilting propulsion units are installed. Wichita State University’s National Institute for Aviation Research (NIAR) assisted with construction of the wing.
With Textron Aviation’s longtime reputation for conservative yet practical aircraft design, it’s no surprise that entry into service of the Nexus isn’t scheduled in the near term. “I think we're very pragmatic about this space,” said Textron eAviation president and CEO Kriya Shortt. “Our plan for entry into service would be in the 2030s, which we think is the culmination of technology, of the regulatory environment, and of the market itself.”
Capable of carrying four passengers and one pilot up to 60 miles with the current battery system, Nexus will—like all of Textron Aviation’s products—be available for whatever use case the customer desires. This could be an air taxi business model, air ambulance, or for special missions and military uses, Shortt acknowledged. The cabin interior has more cabin volume than a Cessna T206 single-engine airplane, according to Terry, although the overall airframe footprint is larger.
“We want to have a vehicle that is multi-mission-capable, that answers the needs of our customer base,” said Shortt. “One hundred plus years of experience across the Textron business units in the aerospace sector gives us the opportunity to make sure that the product is going to have broad appeal, which we think is what our customers expect from products that are designed and manufactured by Textron.” 
NIAR is also hosting the ground test facility for Nexus. Planned to be operational by the end of this year, the facility includes a control station and a ramped structure on which Nexus will be restrained during testing of its propulsion systems.
“It’s funded by the state of Kansas to help strengthen aviation industry technologies” under the Kansas Aviation Research and Testing Growth Initiative, explained Andi Meyer, manager of engineering. “It's going to allow us to test the aircraft in a fully restrained manner, so it's a controlled environment. We can assess how that aircraft behaves, what the performance is like, what the thrust characteristics are like, all from the safety of not leaving the ground. We'll be able to test everything we need to test before we go to flight test, so it's a really important milestone on our path to certification and on our path to flight testing.”
The 15-foot-high, 20-foot-wide elevated ramp’s design has a specific purpose: to allow testing high enough to eliminate the influence of ground effect, which amplifies lift when a wing is near the ground. Data from the aircraft and load cells built into the ramp will be sent to a mission control station on the NIAR grounds. “We’ll be able to watch all of this testing occur from very nearby,” she said.
Housed in a moveable trailer, the ground control station will also be used for remote piloting during flight testing. The trailer has two levels, one with equipment and workstations, then a stairway leads up to a piloting platform with large windows where test pilots can view the action. Being mobile, the trailer will travel with Nexus when remote operations are underway.
Bell, Textron Aviation, and Textron Systems contributed to the telemetry and triple-redundant radio datalink equipment, as well as live video feed. Each datalink operates on different frequency bands, Meyer explained, “so that we have high-integrity communications with the vehicle. It also has redundant inputs for AC power, as well as backup battery power for the AC power and the low voltage that powers avionics equipment.”
Once sent to the trailer, data is fed to workstations in the trailer and elsewhere to engineers monitoring the flight-test activity. “This is like an order of magnitude more complicated than earlier [telemetry systems],” she said.
While Shortt couldn’t offer a timeline for the first untethered flight of the Nexus, she did say that the first contained tethered flight is scheduled for the second half of 2025. “Once we have satisfied ourselves there, [then] we’ll move to the remotely piloted flight, which is the step process. Stay tuned.”
Nexus Simulator
Unlike Textron eAviation’s Pipistrel Velis Electro, which is a conventional airplane powered by a battery-driven electric motor, the Nexus will have fly-by-wire flight controls and envelope protection features that will keep pilots out of trouble. This is similar to the unified flight control concept that other advanced air mobility designers have adopted.
In the Nexus simulator, there are two hand controls and no pedals (what looks like pedals are just a resting place for the pilot’s feet). I gave the simulator a try during our pre-NBAA-BACE visit.
The right stick or inceptor moves the aircraft in three axes. From a hover position, pushing forward or aft, right or left, moves the Nexus in the direction of inceptor movement, while maintaining the hover altitude and level attitude. Twisting the inceptor induces yaw left or right. 
“This is the hover mode,” said Terry, “and our control laws and our software are pretty mature in the hover mode. It flies pretty much like you'd expect, like a highly augmented drone.” Once you’ve flown to where you want Nexus to be, just remove your hands from the inceptors, he explained, “and it's going to go and latch onto your position and altitude. The idea is it's really easy to fly as a pilot, so if there's wind or disturbances, the control laws will handle that. You just tell it where to go, and the control laws handle the rest.”
To change altitude, I just move the left inceptor forward to climb or aft to descend (straight up or down). “If you leave the stick in the detent or don't touch it, it'll hold your altitude as you make all your other changes,” Terry said.
When I pointed out that it seemed unintuitive to have the vehicle climb with a forward push of the left inceptor, he explained that a video game grip is used on the left side. This will be replaced by a thrust-lever-style grip, which will respond to a push by increasing thrust. But this all has to be integrated with what’s going on with the propulsion units, with the two forward and two wingtip propulsion units able to convert from vertical to forward lift.
“The control law is pretty mature,” Terry said. “In hover, we can do the conversion and go to forward flight…but we intend to make it a lot easier to fly as we keep working on it.”
To enter the conversion mode in the current setup, I pushed full forward on the right inceptor and the Nexus maxed out at 20 knots. After moving a small switch on the inceptor to engage the conversion, I could then let go of the inceptor. A display showed the position of the forward and wingtip nacelles as they shifted from vertical to horizontal, while I managed pitch guidance on the primary display that guided me “through the conversion corridor,” as he explained it.
Now Nexus was flying in a more traditional airplane mode, and pulling aft or pushing forward on the right inceptor induced pitch changes while left and right moves induced bank. Turn coordination is automatic so there was no need to twist to induce yaw, and Nexus automatically compensates for lift changes during the turn so I didn’t have to pull the inceptor aft while in a turn as I would in a normal airplane. 
“Eventually we intend to add additional loops on top of this,” he said, “so it'll be extra augmentation. The idea is it's going to be really easy. A lot of that manual flying that you normally have to do as a pilot is handled by the control laws, and so the pilot can focus on [what’s necessary].”
To convert back to hover mode, I pulled the thrust offset back to 20% power then toggled the inceptor switch and let go of the controls, and the simulated Nexus settled back into a hover. “That's been the focus of the control law development—for hover—since our first testing is going to be on the hover,” Terry said.
Expansive eAviation 
There is much more to Textron eAviation than the Nexus eVTOL. Pipistrel, for example, has more than 2,500 airplanes in service, including light sport and ASTM-qualified training airplanes such as the Velis Electro, which is now FAA-approved for sale in the U.S., and the high-performance piston-powered Panthera.
A retractable landing gear single-engine airplane, the speedy Panthera should achieve EASA CS-23 certification in the second half of 2025, and plans call for simultaneous FAA validation. “It'll go 15% further, 10 knots faster, and burn 30% less fuel than its closest competitors,” said Shortt.
Pipistrel’s engineers are also developing the hybrid Nuuva V300 uncrewed aircraft, which will take off and land vertically under electric power and then fly horizontally powered by a Rotax piston engine. Capable of carrying 700 pounds of cargo about 300 nm, the Nuuva features fly-by-wire flight controls, but it will be operated by a ground-based pilot. Eventually, one operator will be able to manage multiple Nuuvas, and the goal is to achieve autonomous operations.
“We see this being an air vehicle that can be used both for disaster relief, where maybe you were unable to get people into a space because of infrastructure, but with its electric vertical takeoff and lift capability, you could deploy a Nuuva,” she said. “[You could] have it be unloaded by people who are on the ground and then return it back for additional provisioning. We see it being very capable for the armed forces and forward deployment of provisions as well as commercial opportunities.”