There are two successful business strategies an aircraft manufacturer might follow when creating a new product. One assumes the new airplane is so innovative that it will create its own market. In the other, an OEM watches a specific market develop until the day it’s ready to launch a competing aircraft, a machine incorporating lessons learned from years of observing competitors in the marketplace. The latter is the strategy Textron Aviation took when preparing the new Denali single-engine high-performance turboprop.
Some might call the single-engine turboprop market a bit crowded if they look only at the last decade’s worth of delivery numbers from the General Aviation Manufacturers Association. The more appropriate word is consistent, with more than 200 airframes delivered almost every year. OEMs love consistency.
The largest single-engine turboprop seller is Cessna’s Caravan series, with 1,062 delivered from 2008 through the second quarter of 2018, followed closely by the Pilatus PC-12, at 901 delivered; Daher’s TBM series, with 535; Piper’s M500/600, at 371; Quest’s Kodiak, at 245; and Mahindra’s Airvan 10, with 52. Prices range from $1.7 million for the Mahindra turboprop to $5 million for a typically equipped PC-12. In between, it’s $2.53 million for a Grand Caravan, $2.98 million for a Piper M600 and $4.22 million for a fully equipped TBM 930. While the Epic 1000 is not yet certified, the company is taking orders for $3.25 million. Cessna is currently taking Denali orders at $4.8 million apiece.
Of course, comparing single-engine turboprops on a head-to-head basis isn’t exactly fair to any OEM, except for the fact that these other airplanes are flying, while the Denali for now is just a sweet mock-up and a collection of parts back home at the factory in Wichita, Kansas. Textron first showed a rough Denali mock-up at AirVenture 2016. For Rob Scholl, Textron Aviation senior vice president of sales and marketing for all commercial products, confidence doesn’t seem to be an issue. He notes that Textron Aviation’s two main divisions, Cessna and Beechcraft, have a long history of delivering impressive aircraft. When it comes to the Denali, “There’s lots of single-engine pilot interest too, including a very strong worldwide special-mission interest. Internationally, the turboprop market has been really strong lately, especially for some of the commercial operators in Europe.”
Scholl says Textron looks for strong markets in which to invest. The company likes the single-engine turboprop market because “it offers a lot of capabilities that customers want. A CJ4 customer saw the mock-up at AirVenture this year and bought one to supplement his jet flying. I think that shows the kind of confidence people have for what we create at Textron, Cessna and Beechcraft. We’ve walked a lot of people through the mock-up over the past few years and gathered lots of customer feedback that led to the current mock-up at AirVenture 2018.”
Where the Denali fits in a market with a half dozen other turboprops, however, is a fair question. Some of the singles offer vast cabins and impressive load-carrying capabilities but fall somewhat short on speed for personal transportation, like Cessna’s Caravan or Quest’s Kodiak. There are smaller-cabin aircraft offering blazing cruise performance, like the TBM 930, Piper’s M600 and the Epic 1000, but these airplanes feature cabins some operators might consider tight. The Piper M600 offers the smallest cabin, at 197 cubic feet, followed by the Epic, at 237, and the TBM 950, at 246 cubic feet. The TBM 930’s cruise speed tops at 330 knots, while Piper’s M600 offers a 287-knot machine. The Epic is expected to offer a max cruise speed of 325 knots.
Where’s the Bull’s-Eye?
There are machines that fall somewhere in the middle as well. The Pilatus PC-12, with a 2,257-pound max payload, cruises 100 knots faster than either the Kodiak or the Caravan. The PC-12’s cabin is 405 cubic feet, larger than the others, although the Denali’s cabin is designed to be 5 percent larger than the PC-12’s. Of course, at 287 knots, the PC-12 is not as speedy as the smaller-cabin turboprops, but at a similar 285 knots, neither will the Denali. Both the PC-12 and the Denali come equipped with pressurization, huge cargo doors and trailing-link landing gear for rough-field comfort. The PC-12’s certified ceiling is 30,000 feet, versus the Denali’s 31,000 feet. The PC-12’s 1,845 nm maximum range (1,680 nm with one passenger) outdoes the Denali’s, at 1,600 nm. The Denali will weigh less than 12,500 pounds to prevent the need for a type rating, but at the moment, Cessna hasn’t released a gross weight number, nor any performance figures. Those won’t be made public until after the Denali’s first flight next year. Like all the other models, the Denali will be certified for operations by a single pilot.
At $5 million, the PC-12 is priced a bit higher than the Denali, no small sum for either single-engine turboprop considering that for the same amount of money a customer could buy an Embraer Phenom 100EV, a HondaJet or two Cirrus SF50 Vision Jets, all of which are also single-pilot certified. The PC-12 is powered by a 1,200 shp flat-rated Pratt & Whitney Canada PT6A-67P, while the Denali will use the new GE Catalyst engine flat-rated to 1,240 shp.
Denali’s cockpit comes with Garmin’s G3000 avionics suite, which offers three 14-inch diagonal widescreen LCD displays, as well as two touch-screen control panels. The G3000 system will deliver synthetic vision, dual flight management systems with WAAS-enabled GPS receivers, dual transponders with ADS-B In and Out, and digital weather radar. The Garmin G3000 system includes a terrain awareness and warning system, traffic collision and avoidance system, dual air-data computers and a digital cockpit audio system. A Garmin spokesperson says the Denali’s G3000 will also add engine instrumentation and CAS messaging depicting operating parameters, in addition to voice recognition and Bluetooth connectivity for the flight deck. The Denali’s Garmin Voice Command uses automatic speech recognition technology to reduce pilot workload for some common cockpit tasks.
The Denali’s interior design efforts are a product of the same Textron teams in Wichita that create the rich feel inside Cessna’s high-end jet aircraft. Entering the mock-up’s cockpit, the lush beige leather seats caught my attention. I found them quite comfortable and easy to adjust. Cessna worked hard to eliminate as many switches and knobs in the cockpit as possible, allowing the touch-screen controller to handle many tasks, such as radio communications and flight-data entry and updating. The instrument panel is all black, as are the lower side panels, making the cockpit’s clean lines resemble those of an expensive sports car. Once seated in the mock-up, everything I’d need to operate the airplane was in easy reach, such as the landing-gear handle on the left side of the power lever. The Denali features both an electric and a manual trim system. Cockpit visibility should be good from what I could see in the mock-up, but a final judgment will need to wait until a first flight. An important Denali feature is the single power lever and propeller control used to manage the 1,240 shp GE Catalyst engine that Cessna says will deliver a jetlike experience to pilots.
Inside the Airplane
Looking closer at the Denali, it will be 48 feet 9 inches long by 15 feet 2 inches high, with a 54-foot-3-inch wingspan. The aircraft’s forward airstair door comes standard with a gas-spring counterbalance and a solid folding handrail, while the cargo door’s closing mechanism is electrically controlled. The basic Denali cabin comes with seating for six in the back and two in the cockpit, as well as a refreshment center. A belted lavatory seat is optional, as is the external lav servicing unit. Why anyone would not choose external service is a mystery. The Denali’s quick-change interior options allow for as many as nine seats in the cabin or the ability to completely remove all and configure the aircraft for cargo duty.
Carrying four passengers, the Denali will fly 1,600 nm at a max cruise speed of 285 knots. At the aircraft’s 31,000-foot service ceiling, the Denali’s 7.55 psi cabin differential will mimic an aircraft flying at 6,130 feet. It will also maintain a sea-level cabin up to 18,500 feet. The size of the Denali’s fuel tank will be determined by altitude test data after first flight.
The aircraft’s square-oval-shaped fuselage uses all-metal construction to create a flat-floor cabin 4 feet 10 inches tall and 5 feet 3 inches wide. The Denali will use a few composite components, including the winglets, weather radar housing and a number of fairings. The wing is a new Cessna design of primarily aluminum construction with a few titanium components. The wing features four large, electrically driven Fowler-type flaps for good low-speed handling during short takeoff and landing operations.
Scholl speaks to what Textron, Cessna and Beechcraft have learned about aircraft design over the years. “A lot of things in the Denali are a natural progression from the Latitude and the Longitude, such as monolithic machining. Instead of creating hundreds of individual parts, we take a single piece of metal and machine it out. While the cost of the final part is a bit higher, the overall weight is somewhat less, and we get a much better fit.”
Cessna used this kind of manufacturing on the Latitude door and with the Longitude wing skins. The Denali, Scholl says, is going to take this to a new level, with even more monolithic machining and more automation in the manufacturing process. He adds that the new construction system allows for a quicker build of each airframe, although the company won’t disclose that precise figure. The Denali’s warranty numbers include five years on the airframe, avionics, engine and propeller, three years on aircraft parts and two years on paint and the interior.
Under the Hood
A significant part of the Denali’s performance will be due to the new GE Catalyst engine, which the company has been working on for the past five years. The Denali will be the first certified aircraft to fly with the new 1,240 shp turboprop power plant. Paul Corkery, GE’s general manager for turboprops, says the Catalyst engine is “the first clean-sheet turboprop designed to be mass manufactured in 30 years,” adding that certifying a new engine today is a much more complex process than it was a few decades ago.
For GE, a clean-sheet design meant just that, Corkery says. GE is leveraging the knowledge the company has gained over the past few decades of building engines for the commercial airline side of the industry, such as versions of the Boeing 777 and 787. “We decided to build a brand-new [turboprop] engine because we wanted to be a player in this market space.” With the Catalyst, “We’re bringing a higher 16-to-1 compression ratio to this engine — 50 percent greater than competing engines — as well as variable geometry to maintain tighter performance over a given flight profile.” Corkery says the higher compression ratio should deliver a 15 percent better fuel burn. In addition to more power available at higher altitudes with the Catalyst, there’s also a 20-pound weight savings over an engine created using conventional construction techniques. More important, Corkery says, “We simply could never have created an engine like the Catalyst using older traditional methods of construction.”
GE is building the Catalyst engine using additive technology, more commonly known as 3D printing, similar to what’s in use at Cessna. Corkery says, “In fact, this is our first engine to use a significant amount of additive parts.” So effective is the additive manufacturing process that Corkery says, “We took about 800 traditional engine parts and reduced that number down to just 12.” The new additive manufacturing system “helps us reduce our design cycle.” Updating the engine as it develops is also much simpler because software changes represent the major updates, not manufacturing of new parts.
The Catalyst uses dual fully automatic digital engine controls to provide the proper fuel flow and propeller control to the five-blade reversible-pitch 105-inch-diameter composite McCauley prop. The engine also includes an electronic backup to the dual-channel fadec. The fadec not only offers engine over-speed, over-temperature and over-torque protections, but also eases pilot workload by offering a single-button engine start and, of course, that previously mentioned single-lever power control. GE is currently ground testing two Catalyst engines and is scheduled to begin high-altitude and icing tests over the next six months. When asked about the engine’s timetable, Corkery says GE is in sync with Cessna’s production team and is on schedule to receive FAA certification in the first quarter of 2020.
Corkery says the Catalyst represents a huge investment for GE, a gamble the company hopes to turn into a profitable product by placing these engines on other aircraft too, such as those in the modification market for existing turboprops. With the engine’s upper thermal limit of 2,000 shp, “it would be fair to say there will be a family of Catalyst engines coming down the road,” he says. So successful has development been to date that GE has created more than 100 patents on the 98 new technologies used in the Catalyst. The new engine’s schedule calls for no overhauls or major inspections during the first 4,000 hours.
The Denali structural test aircraft, the first flying prototype and the first two production aircraft to be used in the flight-test program were built in Cessna’s experimental hangars W2 and W3 on the east side of Wichita’s Dwight D. Eisenhower National Airport. Textron says final production of the Denali will eventually be moved to Textron’s Plant 4 on the east Wichita campus, where the Bonanza, Baron, King Airs and Citation Longitude are built.
The Denali’s first flight is expected early next year, with an entry into service during the first half of 2020. TRU Simulation + Training, another Textron subsidiary, will handle Denali training and is already at work on a simulator that might be located either in Tampa, Florida, or Carlsbad, California, a TRU spokesperson says.
If you visit the Pilatus website, you’ll notice a slogan that reads: “Nothing else compares” to a PC-12. Perhaps not in every detail, but if the Denali lives up to its performance expectations, it should give the PC-12 quite a run for its money.
Note: This story was updated since the print edition appeared.
|Engine||GE’s catalyst delivers 1,240 shp|
|Propeller||McCauley five-blade composite|
|Seats||8 to 11|
|Fuselage Length||48 ft. 9 in.|
|Fuselage Height||15 ft. 2 in.|
|Wingspan||54 ft. 3 in.|
|Cabin Length||29 ft. 6 in.|
|Cabin Height||4 ft. 10 in.|
|Cabin Width||5 ft. 3 in.|
|Cargo Door||4 ft. 2 in. by 4 ft. 3 in.|
|Max Gross Weight||TBD|
|Full Fuel Payload||1,100 lb.|
|Max Usable Fuel||TBD|
|Max Operating Altitude||31,000 ft.|
|Max Cabin Differential||7.55 psi|
|Sea Level Cabin Up To||18,700 ft.|
|Cabin Altitude At||31,000 ft. 6,130 ft.|
|Max Speed||285 kts|
|High Speed Cruise||285 kts|
|Max Range||1,600 nm with 1+4 pax|
|Takeoff Distance||2,900 ft.|
|Engine TBO||4,000 hours|