Phoenix, Arizona-based engine and avionics manufacturer Honeywell (Booth No. 1606) says its entry in the 10,000-pound-thrust engine sweepstakes is well under way. Ron Rich, the company’s director of advanced technologies, told EBACE Convention News that parts for the HTF10000 demonstrator have been ordered, with the core engine expected to be operational by the end of next year. He said the new engine borrows heavily from its smaller sibling, the HTF7000–installed on the Bombardier Challenger 300–which currently has more than 200,000 hours of service.
“Architecturally, the engine is quite similar to that of the 7000, and that is on purpose, to minimize the risks associated with new engine on new aircraft,” Rich said. Honeywell is using a research version of the proven smaller engine, called the Tech7000, as a testbed for new “green” technologies destined for the HTF10000.
“There are three aspects of green when you really get down to it,” said Rich. “One is fuel burn improvement, one is noise reduction and one is emissions improvement. The -10000 will incorporate all three. That’s the suite of technologies we are working on today.”
Among the components to be validated are a new low emissions combustor Honeywell calls Sabre (single annular combustor for reduced emissions), which utilizes what Rich described as rich-quench-lean technology. “What we do is run rich fuel/air ratios in the primary zone of the combustor, then we introduce cooling air rapidly along the combustor axial length to quench that rich air/fuel ratio to lean the combustor out as it enters the turbine,” he said. Rich said he believes this admittedly simple configuration will significantly reduce the engine’s generation of NOx (nitrogen oxides) emissions as well as carbon monoxide, unburnt hydrocarbons and smoke.
The new combustor will use the company’s latest advances in wall and dome cooling to increase component durability. Another innovation is a new forward swept fan which the company believes will improve fuel burn while lowering noise levels. The fan is undergoing engine tests at Honeywell’s acoustic research facility before being scaled up for the HTF10000.
In the turbine section, the company’s metallurgists have developed a new stronger powder nickel-based alloy–being used in turbine discs–which will allow higher operating stresses, resulting in improved engine power density and reduced fuel consumption. According to Rich, the new discs will be running in test engines later this year.
Another metallurgical advance in the compressor resulted in what Rich categorized as an important piece of the HTF10000-class engine puzzle–advanced dual alloy impeller technology. “We are bonding two different alloys together to meet the design requirements for both life and temperature capacity,” said Rich. “In the end it will increase the service life of the component, but it enables the engine to run faster, as well as run higher pressures and higher temperatures with this technology.”
All of these advances are expected to yield benefits not only for the HTF10000, but for other programs as well. “The technology will be very applicable to all turbofan engines that Honeywell builds, including our TFE731 family and also the HTF7000, as well as any other variants that we might build from the HTF7000, such as possible development of an HFT5000 engine–lower in thrust–that would be a complementary improvement to our TFE-731 line in the future,” said Rich.
Honeywell believes the stakes are high for this class of engine, which has sparked competition from Safran’s Snecma division, Rolls-Royce, GE and Pratt & Whitney Canada. Honeywell’s 2007 10-year business aviation forecast predicted that the super-midsize to large aircraft which could utilize this class of engine is on the rise. European operators surveyed by the company last year listed the need for more spacious cabins as their most important reason for replacement aircraft.
Honeywell said it is holding discussions with airframers to find suitable aircraft designs for their new engine as they begin preparations for the full-scale HTF10000 development program. “The timing of that is tied to customer need,” said Rich. “We’ll be operational with our core demonstrator engine at the end of next year and we feel at that point we’ll be ready to move forward based on the business conditions to launch a new program.”