Honeywell says a second generation low-emissions upgrade for the HT7000-series engines could be available as a retrofit option within a "couple of years" if planned durability tests on the company's Tech7000 technology demonstrator engine prove the product is ready.

Called SABER 2 (singular annular combustor for emissions reduction), the technology combines changes to the combustor, fuel nozzles and fuel scheduling to reduce nitrous oxide emissions beyond the 25% cut provided by today's SABER 1 technology in all new HTF-family engines, including the HTF7250G for the Gulfstream G280 and the HTF7500E for the Embraer Legacy 450 and 500. SABER 1 can also be retrofitted into HTF7000 engines on the Bombardier Challenger 300.

Jim Kroeger, Honeywell's director of engineering for propulsion, says engineers are also experimenting with third-generation SABER technologies that he calls "the next breakthrough" in emissions reductions. "With SABER 3 we have gone more radical in the aerodynamic design of the combustor to get the [nitrous oxides] down another significant step," he says.

Other advances Honeywell is pursuing with the Tech7000 include increasing allowable turbine temperatures to boost engine thrust output without increasing engine size.

Kroeger says Honeywell is testing "sporty new" thermal barrier coatings for aerofoils and stators to manage temperature as well as "radical new cooling schemes" inside the turbine. "It's panning out," he says. "We're seeing some growth opportunities in this motor. I think we can get [the thrust] up to over 8,000lb [35.6kN] in the same chassis." The target represents at least a 7.5% increase on the 7,445lb-thrust available for the HTF7250G and HTF7500E engines.

"Customers will keep wanting more thrust," Kroeger says, adding that upgrades would likely be available as a retrofit option, possibly at a "breakpoint" for model improvement.

Source: Flight International