NBAA Convention News

Textron, GE Report Progress on Cessna Denali Turboprop

 - October 8, 2017, 8:01 AM
Cessna is making progress on assembling the Denali test articles. Shown: upper left cabin section of test article three.

In the year since Textron Aviation unveiled its new $4.8 million Cessna Denali single-engine turboprop here, both Textron and engine maker GE Aviation have made steady progress toward a projected first flight in next year's fourth quarter. Brad Thress, Textron Aviation senior vice president of engineering, and Brad Mottier, vice president  and general manager BGA, GE Aviation, recently gave an update to AIN on the program's progress. 

Thress reported that just over half of the aircraft's 7,500 detailed airframe and systems parts have been released into the factory, approximately 4,000 parts total. From that number, about 10,000 parts have been manufactured, including multiples of certain part numbers. “Some of the larger components are coming to fruition, which is always nice to see. We've got the cabin door complete and the large cargo door completed, and those are going in a door test article. Just a couple of days ago we had our first fuselage skin come out of the metal bond shop, so the fuselage skin runs back from the cockpit to where the empennage starts. It's a really large assembly so it's exciting for our folks to see that. So a lot of good progress on the airframe design,” Thress said. “We're generating actual airplane parts and that's fun. You have that time early in a program where you are doing a lot of stuff on [engineering drawing software] Catia and on paper but you are not seeing parts flow out, so this is an exciting time for us so we are staring to see large assemblies come out of the factory and into full-scale test articles.”

Textron Aviation is continuing its human factors work on the aircraft, hosting customers to solicit feedback and employing advanced modeling and simulation tools, Thress noted. “We have a human factors lab where we use virtual reality to take customers through the cockpit and make sure we get their feedback on where things are located. We use flight control iron birds and pilot iron birds as well.”

Thress said Textron's McCauley division has made substantial progress developing the Denali's 105-inch-diameter all-composite propeller that features scimitar-shaped blades. Completed tests include full rpm runs for extended hours and centrifugal loading of the hub, including an out-of-balance condition that simulates blade loss. “The hub has done very well. We've also done blade fatigue testing. Every time a blade goes around it experiences a load cycle. As part of our development testing we do 100 million load cycles, and we've completed that testing on the blade.” Thress said the blade has also been tested to maximum static load and that propeller development testing is nearly ready to give way to certification testing. An example of the new propeller will be on display here at AirVenture. 

The Garmin G3000 avionics system for the Denali is not expected to ship until next year's second quarter, but Thress does not foresee any significant integration issues given Textron's extensive experience with it on the Cessna M2 and Citation CJ3+. “It's a pretty integrated system. You do a lot of neat things through the Garmin touch controller. We're right on track with that,” he said. He also said that Cessna is developing and will be manufacturing its own proprietary cabin seats for the Denali. The aircraft will be available with a standard modular aft lav that can be removed to increase cargo space or an optional permanent lav that can be serviced externally.

GE's Brad Mottier said the Denali's new ATP (advanced turboprop) engine is on schedule for first engine test run by year-end. “All of the initial design work is complete. The detailed parts have been released. And the ATP team has printed all the additive parts. We've taken 855 individual parts and through an additive design and manufacturing process we have reduced that number to 12 and those parts are complete. We also started writing the first engine assembly and disassembly procedures,” he said. The ATP software and fuel controls have been tested on a GE H80 engine at the company's facility in Prague.

Both Mottier and Thress think the ATP engine is the feature, above all others, that will make Denali a real game changer in the single-turboprop space. “The Fadec not only provides a much simpler operation of the engine controls but—because it automatically optimizes the propeller and the engine together as a system—it also provides more power at altitude while burning less fuel than engines that are in the marketplace today, “ Mottier said. “The Fadec also has a digital twin feature for data analytics." The company already uses the feature in its commercial airline engines, using data from every flight and running a computer simulation to know how each individual engine serial number is performing. The result, he said, is lower ownership costs and extended service periods.

“The ability to go to a detent and let a computer do its thing is really revolutionary in this class of airplane,” said Thress. “That's really enabled by the efficiency of the engine. Lower fuel burns and lower direct operating costs.”