Phoenix-based engine and avionics manufacturer Honeywell says its 10,000-pound-thrust engine contender is well under way. Ron Rich, the company’s director of advanced technologies, told AIN that parts for the company’s HTF10000 demonstrator have already been ordered, with the core engine expected to be operational by the end of next year.

According to Rich, the new engine borrows heavily in architecture from its smaller sibling, the HTF7000–which powers the Bombardier Challenger 300 and currently has more than 200,000 hours of service. “Architecturally, the engine is quite similar to the -7000 and that is on purpose, to minimize the risks associated with new engine to new aircraft,” he said.

Honeywell is using the Tech 7000, a research version of the proven smaller engine, 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. “Fuel-burn improvement, noise reduction and 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 uses what Rich describes 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 believes this configuration will significantly reduce the engine’s generation of NOx emissions as well as carbon monoxide, unburned hydrocarbons and smoke. The new combustor will use the company’s latest advances in wall and dome cooling in an effort to increase component durability.

Engine Innovations
Another innovation is a new forward-swept fan that the company believes will improve fuel burn while at the same time 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–that 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 categorizes 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,” he said. “In the end it will increase the service life of the component, but it enables the engine to run faster; this technology enables us to run at higher pressures and higher temperatures.”

All of these advances are expected to yield benefits not only for the HTF10000 but also for other programs. “The technology will be applicable to all turbofan engines that Honeywell builds, including our TFE731 and also the HTF7000, as well as any other variants that we might build from the HTF7000, such as possible development of an HTF5000 engine–lower in thrust that would be a complementary improvement to our TFE731 line in the future,” said Rich.

Honeywell believes the stakes are high for this class of engine, which has sparked competition from Snecma, Rolls-Royce, GE and Pratt & Whitney Canada. The company’s 2007 10-year business aviation forecast predicts that the number of super-midsize to large aircraft that could use this class of engine is on the rise. European operators Honeywell surveyed last year reported that the need for a more spacious cabin is driving their desire for replacement aircraft.

“There’s an opportunity showing itself with the OEMs, with the airframers, that there’s a new class of aircraft that wants to be built that needs engines in the 10,000-pound-thrust class. We have a significant business interest to be part of that and we have shaped our plans to meet what we believe are the customers’ needs,” said Rich.

Honeywell said it is in discussions with airframers to find suitable aircraft designs for the new engine as it begins 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 2008, and we feel at that point we’ll be ready to move forward based on the business conditions to launch a new program.”