GE Aviation is progressing toward the installation of its new Catalyst turboprop engine on the new Cessna Denali following the completion of ice testing of the powerplant, the engine maker said this week. In the past two winters, the company has been running the engine in below-zero temperatures in what it calls “icing critical point analysis” at the National Research Council in Ottawa, Canada.
Using a 10-meter-long wind tunnel connected to the outside, engineers draw in outside air and mix it with super-cooled liquid droplets sprayed inside the tunnel. This generates atmospheric conditions and in-flight temperatures that are channeled to the engine as clouds comprising small drops at sub-zero temperatures and simulates the variability of altitudes up to 30,000 feet. GE Aviation senior engineer for inclement weather Paolo Vanacore explained that when temperatures fall below -20 degrees C, ice crystals that form in the clouds and at higher altitudes and certain speeds are like stones.
“We conducted tests that led these clouds to flow against the engine at extended vertical or horizontal trajectories,” Vanacore added. “This simulated flight maneuvers with variable density and consistency, depending on the temperatures but also on the speed or angle of impact.”
Engineers used eight non-intrusive micro-cameras to verify that the accretion or shedding of ice didn’t affect the engine’s mechanics or operation and performance. “The results were excellent,” said Vanacore. “We even simulated the restart after long inactivity at polar temperatures. The engine’s responses have exceeded expectations. And its anti-ice system demonstrated a high level of reliability even under such extreme weather conditions where an aircraft in service is rarely found.”
In December, GE installed a Catalyst on a Beechcraft King Air 350 flying testbed. Textron Aviation expects the first flight of the Denali turboprop single later this year.