Textron Aviation currently has 19 aircraft in production and is continuing the progression with the development of two new turboprops – the single-engine Cessna Denali and twin-engine Cessna SkyCourier. Differing in design and mission, the products represent new opportunities for the company.
We recently visited with Textron Aviation’s Martin Tuck (technical marketing advisor), Matt Warner (turboprop communications specialist) and Brian Rohloff (vice president of sales) to obtain the latest progress and specifications for both aircraft.
Cessna Denali
The Cessna Denali, first announced at the 2015 EAA AirVenture, is a clean-sheet design from tip to tail. The aircraft is a pressurized single-engine turboprop, with a maximum operating altitude of FL310, cruise speed of 285 KTAS and high-speed range of 1,600 nm (with one pilot and four passengers). The Cessna Denali inherits many design traits from Textron Aviation’s latest jets and has a list price of $5.35 million. The closest competing turboprop aircraft in current production is the Pilatus PC-12. From strictly a price perspective, the Cessna Denali will also compete with light jets such as the HondaJet Elite, Phenom 100EV and Cessna Citation M2.
New Powerplant
While the PC-12 and the TBM 940 utilize versions of Pratt & Whitney Canada’s PT-6A engine, the Cessna Denali will be the launch aircraft for GE Aviation’s new “Catalyst” turboprop engine. General Electric’s Catalyst makes extensive use of modern additive manufacturing (technology highlighted in our August 2019 issue). In talking with Paul Corkery, turboprop manager for GE Aviation, this manufacturing technique allows GE to reduce 855 parts that might have previously been manufactured using traditional processes to 12 by way of 3D printing. The resulting component is a single piece which not only reduces complexity and weight but can also increase cooling efficiency. In July, I had the opportunity to inspect a 3D printed model of the Catalyst engine as well as an actual Inconel 718 alloy component with an intricate internal design. The internal channels and structures would have been difficult, if not impossible, to duplicate using previous processes.
I also discussed the design with Simone Castellani, systems manager at Avio Aero – a GE Aviation company. Avio Aero had the opportunity to optimize the operation of the Catalyst based on years of experience designing larger commercial turbine powerplants. In addition to a substantial reduction in the engine’s part count, GE will use innovative designs to eliminate the traditional propeller governor as well as incorporate a jet-like dual-channel FADEPC (Full Authority Digital Engine and Propeller Control). This feature will control virtually all aspects of the engine and propeller operation from start to cruise to descent. The pilot will move the single-power lever to idle position, press the start button, and the FADEPC will take over the start process. This system will offer pilots and owners advantages in efficiency along with protection from exceedance of temperature or torque limitations, reducing potential engine damage.
The engine will turn a McCauley Blackmac five-blade composite propeller and provide 1,300 shaft horsepower. With the new design, GE is offering a 4,000-hour TBO with no fixed hot section inspections between overhauls. The engine also incorporates a sophisticated trend monitoring capability. As GE gains operational experience with the engine, the TBO is planned to increase to 5,000 hours.
As of this writing, the Catalyst has undergone more than 1,200 hours of operation in test cells and recently completed high-altitude testing in a chamber that replicated a flight altitude of FL410 – extremely impressive for a turboprop. This fall, GE will mount the Catalyst on one wing of a Beechcraft King Air 350i for in-flight testing.
Flight Deck
The Cessna Denali will utilize the widely-implemented Garmin G3000 avionics suite. Textron Aviation has taken advantage of the integration features of the G3000 to integrate most of the systems into the GTC (Garmin Touch Controllers). This will provide pilots a very clean cockpit, with fewer switches and controls than traditional flight decks.
After spending time in the Cessna Denali mock-up, I found the flight deck to be very comfortable, even for tall pilots. It is easy to get into the seats, and once in them, you have ample room and excellent visibility.
Textron Aviation is including AReS, their automated systems diagnostics capability, standard. If operators wish to have in-flight transmission of the data, they can opt for the Garmin GSR 56 Iridium transceiver. With this capability, maintenance staff would be prepared to address any in-flight anomalies before the pilot even lands.
Cabin
The Cessna Denali will offer best-in-class pressurization of 7.55 PSID (Pounds per Square Inch Differential), which will provide crew and passengers a cabin altitude of 6,100 feet at FL310, the maximum operating altitude. This alone will provide a significant amount of passenger comfort, especially on long-range flights.
The Cessna Denali will initially have two seating configurations: A six-seat executive option with a forward refreshment center and optionally-belted aft toilet; or a commuter option with nine seats in the cabin, but no refreshment or toilet installation. The toilet can either be a permanent externally-serviceable option or one that is self-contained and removable. Operators cannot switch between the executive and commuter cabin implementations.
In the cabin, which incorporates styling features from the Citation line, I was impressed by the large windows and expansive view. The Pilatus PC-12 and Cessna Denali have the same cabin length, while the Cessna Denali is taller by 2 inches and wider by 5 inches. The forward door will offer a stair design that is similar to Cessna’s newest jets. In addition, the airplane will have a standard rear cabin door that is the same width as the PC-12, but a few inches taller. I’ve used the large door of the PC-12 to load an X-ray machine on a pallet during relief work in Haiti, and I can envision the Cessna Denali will be equally useful in such situations.
Next Steps
I’ve viewed the construction of the Cessna Denali prototype, as well as the two production test articles that will be used in the certification. It is impressive to see the design using many processes that Textron Aviation utilizes in their newest jets, including monolithic machining (machining components from a single piece of material rather than forming them). With first test flights expected by the end of this year and production in late 2020, it will be exciting to soon see a new single-engine turboprop in the air.
Cessna SkyCourier
When the need is to move large cargo over short distances, many operators including FedEx opt for the Cessna Caravan. From its first flight in December 1982, the Caravan has proven itself to be a versatile aircraft, giving operators options from freighter and executive transport to amphibious operations.
With the success of the Cessna Caravan, and the increasing need for similar transportation but increased cabin payload, Textron Aviation embarked on the development of the Cessna SkyCourier, a high-wing twin-engine turboprop. FedEx is the launch customer with an initial order for 50 aircraft.
Performance
The Cessna SkyCourier is designed to be a workhorse, with the ability to fly multiple flights in a single day into a variety of airports. The airplane has an MTOW of 18,560 pounds and will be certified under the updated Part 23 category requirements. With a maximum cruise of 200 KTAS and typical high speed cruise of 190 KTAS, the Cessna SkyCourier will be able to fly up to 900 nm at maximum range speed of 165 to 170 KTAS.
Textron Aviation is utilizing Mainten-ance Steering Group (MSG-3) design principles which were created to specifically improve the engineering, and subsequent maintenance, of aircraft. These principles are instrumental in reducing ongoing operating costs for owners. The Cessna SkyCourier will offer extended inspections in comparison with other comparable aircraft using these techniques. Fewer inspections result in a significant decrease in maintenance costs for operators.
Powerplant
The engine will be a Pratt & Whitney Canada PT6A-65SC, with the “SC” standing for SkyCourier. The PT6A-65SC will include a torque limiter and maintenance-related improvements and offer a TBO of 6,000 hours. The SkyCourier will also utilize PWC’s FAST trend monitoring. FAST, which stands for Full Flight Data Acquisition Storage and Transmission, will be able to transmit engine operating data within minutes of engine shutdown. This extensive monitoring will enable maintenance on-condition rather than specific cycles or hours. The new engine will offer 1,100 shaft horsepower driving the McCauley four-bladed aluminum propeller and remote oil level sensing directly on the Garmin G3000 for easy inspection. For operators desiring more extensive systems monitoring, the Textron AReS diagnostic system is an option.
Cabin
Initially, the plane will be offered in either a dedicated freighter configuration (with no cabin windows, or a flexible design with windows and the capability to carry passengers), or cargo, or both. The advantage of the latter is the aircraft can be used to carry up to 19 passengers during the day then quickly transformed for cargo at night. For passengers, the Cessna SkyCourier offers expansive windows and USB power ports at each seat. Both configurations will have the same large cargo door in the rear, as well as forward crew doors on each side for easy access to the flight deck and cabin.
In the cargo configuration, the Cessna SkyCourier will have a maximum cargo payload of 6,000 pounds. If the operator configures the aircraft in the commuter configuration, the maximum payload decreases to 5,000 pounds due to the weight of the different interior.
The SkyCourier will be equipped with the latest G1000 NXi integrated flight deck with 12-inch displays. Since FedEx is the launch customer, this configuration will provide continuity with similar avionics in the Cessna Caravan. As with the Caravan, the Cessna SkyCourier will offer FIKI as an option, which dramatically reduces costs for those operators where in-flight icing is not an issue.
For the targeted operations, most flights will be at lower altitudes, however, the unpressurized Cessna SkyCourier does have a maximum operating altitude of FL250. Since the aircraft is designed to be rugged, it offers a fixed-gear as well as single-point refueling to speed the turnaround process for high utilization.
First flight is expected in 2019, and the current list price for the freighter version is $5.5 million with the commuter version sitting at $6.5 million. As with the Caravan, I wouldn’t be surprised if the possibilities for the Cessna SkyCourier continue to expand as the plane develops and customers see the potential capabilities.
