Honeywell gamme civile

Honeywell is exploring a raft of new aerodynamic, material and design technologies for a possible “next-gen” TFE731 family, as well as for growth versions of its HTF7000 series, the latter of which “maybe could go up to 9,000- or 10,000-pound thrust,” says Jim Kroeger, director of engineering for propulsion. “10 K is an area we are paying a lot of attention to, even though there aren't any competitions,” he adds.

Honeywell's original HTF10000 concept was shelved because “the platforms we were targeting seemed to grow away from 10,000 pounds and it was tough for us to change it without a radically different architecture,” says Kroeger. Since then, the market has continued to evolve, and concepts in the 10K arena are once again in the offing. “There seems to be a gap in the market there with long-range platforms, bigger cabins and high speed. The original equipment makers see all that market growth in the Asia-Pacific region, but what will come in below that? What sort of engine will that be? That's where our attention is focused.”

The company is studying more-efficient, forward-swept, blisked rotor fans which “would apply frankly to the whole range” as a possible means of developing that next-gen TFE731 or HTF7000-series engine, says Kroeger. Also known as integrally bladed rotors (IBR), the blisk concept could be used to boost existing architectures to higher bypass ratios of 6:1-plus without any increase in overall fan diameter. “This is important for business jets, which like to direct climb to 43,000 ft. and cruise at Mach 0.8 for one to two hours. Engine frontal area becomes part of the total equation,” says Kroeger, who adds that “a number of blisk fans are under test.” The fans are sized for the TFE731-60 Falcon 900EX engine. “Next will be an HTF7000,” he says.

Along with fan changes, Honeywell is also working a series of technology programs to improve compressor efficiency. “As we push power density we will see centrifugal compressor engines go up to higher thrust levels.” Together with weight-reduction efforts through increased use of composites and other non-metallics, Honeywell also continues to test new thermal-barrier coatings for higher temperatures as well as innovative turbine-cooling approaches. Further developments of its Saber (singular annular combustor for emissions reduction) combustor technology are also under way to reduce nitrous oxide emissions beyond the reductions provided by the initial Saber 1 standard in the HTF7250G for the Gulfstream G280 and the Saber 2 in the HTF7500E-powered Embraer Legacy 450 and 500. Saber 1 can also be retrofitted into HTF7000 engines on the Bombardier Challenger 300