“It’s been a good exciting year,” said Rob Scholl, Textron Aviation senior v-p, sales and marketing, at a pre-NBAA show briefing at company headquarters in Wichita, Kansas. “We’ve seen market conditions improve, and across the product line we’ve enjoyed good activity."

Since 2013, Textron Aviation has delivered more than 900 jets and 1,100 turboprops and certified 10 new airplanes, backed by an investment of more than one billion dollars in new products, he said. “We really do stand by business aviation and general aviation.”

As of mid-September, Textron Aviation had delivered 136 Citation Latitudes, which have logged more than 115,000 flight hours. “It’s outselling the competition by four to one,” Scholl said. “We couldn't be more thrilled with how this airplane has been received and how it's performing.”

The newest and largest Citation, the 3,500-nm Longitude, was close to achieving certification before to the start of NBAA-BACE, with deliveries to begin shortly after approval of the new jet’s type certificate. At the Wichita factory, the 20th Longitude was already on the assembly line.

During a recent demonstration tour, the Longitude flew a leg of 3,603 nm with five passengers, from Columbus, Ohio, to Paris, aided by 52-knot tailwinds.

Progress continues on Textron Aviation’s newest designs, the single-engine turboprop Denali and the twin-turboprop utility SkyCourier. Cabin mockups of both airplanes are located at Textron Aviation’s NBAA-BACE static display exhibit at Orlando Executive Airport. The entire Textron Aviation fleet is also on display, including the Longitude with a production interior.

VR Prototyping

During the pre-NBAA-BACE visit, journalists took a tour of Textron Aviation’s Industrial Design Studio, where preliminary work is done to refine new airplane designs.

One of the first steps in the prototyping process, before any metal is cut, is to develop a virtual reality (VR) version of the design. Engineers, pilots, company managers, and potential customers can put on HTC Vive VR goggles and view a virtual representation of the cabin and flight deck.

With the goggles on, I could see what it looks like to look through the cabin windows outside the virtual SkyCourier. I could sit in the flight deck and reach out to virtually touch controls and buttons with digitally represented hands, which looked like colorful bony virtual appendages when looking through the VR goggles. In this VR version, the user sits in a chair and doesn’t physically move around. There is no haptic feedback for the virtual hands, but it’s still helpful to see which controls can be reached.

“You can start to interact with this thing before it's ever been built and get a feel for what it looks like,” said Chris Pinkerton, an engineering manager in the design studio.

An example of how this helped designers was the pilot’s view of the wings and what it looked like with the ice light shining for to check for ice accumulation. “Initially we thought we had a problem,” he said. “It was the prop that was obscuring the visibility to the wingtips. We did a whole study here in the shop with plywood and replicas to confirm that we had the sight lines that were necessary. It’s kind of a fun example of how we can use this tool to identify things we need to work on or things that are working well.”

Another tool in the studio is augmented reality, where people can don Microsoft HoloLens augmented reality (AR) glasses and walk around the outside of a rough mockup of portions of the airplane to see how it looks in true scale.

“You can see through the lens so when you're looking at the models, you're bringing them into your space instead of viewing them in a purely digital space,” Pinkerton explained.

The AR tool is useful for human factors evaluations. For example, engineers 3D printed a mock battery that they pretended to install and remove from the SkyCourier to test maintenance procedures. “They get inside the augmented model and practice the routine to see if it was too hard to reach,” he said. “What you'll get [with the AR tool] is the sense of scale. Since the model is in the room and you're seeing the context of the room, then you start to understand how tall things are, how wide they are.”

Another way that engineers use the AR tool is to add animations of doors opening and closing, which is a useful way to see how the SkyCourier’s cargo door operates. Voice commands are incorporated in the tool so engineers can quickly swap from the SkyCourier’s passenger interior and cabin to the freight version, which has no windows or cabin seating.

“We get feedback as to what people like and don’t like and iterate on the design,” said Pinkerton. “We deal with the aesthetic world. Disciplines that are represented are industrial design, mechanical engineering, electrical engineering, aeronautical engineering, and an array of skilled craftsmen that can then take some of the ideas and build replicas and prototypes.”

These early prototypes take further shape in a physical mockup of the cabin, called Aimee, which is phase two of the process in the studio.

Textron Aviation has patented the design of the Aimee mockup tool, which is made of wood and equipped with adjustable clamps that hold vertical wooden stakes on the outside. The stakes move in and out to change the cabin dimensions, so any size cabin can be replicated. Inside this model are fabric “walls” that move along with the setting of the adjustable stakes. The mocked up cabin is also fitted with items that typically fill the space inside a real aircraft, such as representations of seats, divans, consoles, overhead valences, etc. “The point is to iterate as easily as possible,” said Pinkerton, “and make the design better.”

Once the shape is settled on, then engineers turn that into aesthetic designs that can be crafted into a mockup of what the real cabin will look like, and this is what is on display at shows until the actual airplane makes its debut.

Denali Details

Meanwhile, three Denali airframes are well under way in the Wichita factory. The fuselages for the prototype and first flight-test articles are nearly complete, as are flight controls, with wings starting construction in assembly jigs.

Metal bonding is a key technique, especially for wings, which helps lower the number of potential fuel leakage pathways. Another assembly technique that is well-proven in Citation jet manufacturing is automatic drilling, which saves many man-hours and prevents injury. A crawler-driller from the old Beechcraft factory used on the Hawker 4000 program is employed for this purpose on the Denali program.

Modern assembly techniques, including careful routing of edges where major assemblies are attached together and pin-locating tools, make for extremely precise mating of the cabin to the nose and tailcone and other structures. Many large parts are either monolithically machined from a single aluminum billet, such as the wing spar and main entry door, or chemically milled, as is the titanium firewall, cutting down on hole drilling and the number of fasteners needed.

GE will be flight testing the Denali’s Catalyst 1,240-shp engine on a King Air 350, including the engine’s single-lever power control. All work in on schedule for first flight in early 2019, followed by certification in 2020.

The $4.8 million Denali is designed to cruise at 285 knots and it will have a full-fuel payload of 1,100 pounds, giving it a range of 1,600 nm at high-speed cruise with one pilot and four passengers. Avionics are Garmin’s G3000 suite, which includes ADS-B Out, TAWS, and solid-state weather radar.