Goodrich is moving the technology of dual-channel full-authority digital engine controls (Fadec) into smaller and smaller turboshaft engines. At Heli-Expo’09, the company (Booth No. 3241) is showing dual-channel Fadec systems like the unit installed on the 1,050-shp Pratt & Whitney Canada PW210S that powers Sikorsky’s new S-76D, which made its first flight on February 7. “This is the first dual-channel control on a turboshaft engine,” said Tony Gentile, Goodrich vice president of marketing and programs.
The company certified a dual-channel Fadec on Honeywell’s HTS900, which had been slated to power Bell’s canceled 417 and the Army ARH. The HTS900 Fadec received FAA certification last December. It is also developing dual-channel Fadecs for Turbomeca’s Ardiden, Arriel and Arrius engines, according to Gentile. The 1,000-shp power level is where most dual-channel Fadec development is taking place, he added.
Goodrich was among the first fuel-control companies to provide Fadec for small helicopter turboshafts, with the single-channel system for the then-Allison 250 (now Rolls-Royce). This Fadec features a mechanical backup, which is less capable and weighs about the same as a full hydromechanical fuel control. “The mechanical control will let you get home,” Gentile said.
Dual-channel Fadec development should accelerate because, he said, “Today dual-channel control costs less than single-channel with mechanical backup and far less than mechanical controls.” The operational advantages of dual-channel Fadecs make a compelling case for engine and airframe manufacturers to adopt the technology. Engine operation is much more efficient and protection is provided against over-temping and over-torquing. Dual-channel Fadecs also include detailed engine trending and diagnostic information, Gentile said, “allowing smart maintenance as opposed to hard-time component replacement.”
Engine and airframe manufacturers will eventually adopt dual-channel Fadecs for smaller engines and rotorcraft, according to Gentile, but one reason that hasn’t happened already is that Fadec prices don’t drop as the size of the unit drops. The technology is pretty much the same no matter the engine size. “The challenge is to take the control system on a 600- or 700-shaft-horsepower engine and get the cost down. We’re working on that. If I went to Rolls-Royce and said, ‘I can give you a dual-channel Fadec for no more cost than a hydromechanical system,’ there’s little doubt [they would buy it]. I do believe it will happen, and so does Rolls.”