Honeywell is sketching out a small/mid-power turbine engine strategy for light single and twin commercial and military helicopters, as well as unmanned air vehicles, around a two-pronged approach based on technology from the Small Heavy Fuel Engine (SHFE) demonstrator, and a growth derivative of its latest turboshaft dubbed the HTS900X.

The exact path is still evolving, and depends on the given application and power required within the 500-1,500shp (370-1,120kW) range, says Honeywell technical sales director Rick Buchanan, adding: "We just don't know yet."

The HTS900X will be based on the HTS900, the -2 version of which is due for certification in the third quarter, infused with technology from the SHFE demonstrator. The 900X could be available from 2010-11, while the current timing for applications based around the SHFE itself is from 2013.

"The SHFE is a great science and technology programme and may morph itself into the -900X," says Buchanan, who says the "SHFE is working on getting technology to TRL6 [technology readiness level 6, or pre-full-scale development], and in the longer term we could develop SHFE itself into a next-generation engine."

Honeywell completed the first full-engine test of the SHFE demonstrator in Phoenix, Arizona in late February. Two previous tests in September 2005 and October 2006 focused on the core engine, including assembly, starting and operating functions as well as aerodynamic and mechanical mapping.

The SHFE programme began in 2003 and is a 46-month, $46 million equal partnership between Honeywell and the US Army to demonstrate technology for 500-1,500shp engines with 50% higher power-to-weight ratio, increased turbine temperatures and reduced noise and emissions over today's engines (Flight International, 27 February-5 March).

"We're aiming at applications like light commercial twins and UAVs, as its low weight and size makes it very good for these," says Buchanan. Strategic decisions yet to be taken include choosing the most suitable architecture. "Right now the HTS900 has a single-power turbine stage, while the SHFE has a dual-power turbine," he says.

The SHFE otherwise shares several features with the higher-power HTS900-2-1D under development for Bell's ARH-70 armed reconnaissance helicopter, such as dual centrifugal-compressor stages and a single-stage high- pressure turbine.

Source: Flight International