General Electric (GE) is developing the HF120 engine jointly with Honda for the small HondaJet and midsize Spectrum S40 Freedom business jets. According to GE, the engine is on track for certification but neither it nor Honda would confirm the date for this. GE could not give a firm target period either this year or next year.
In ground tests so far, the partners have run eight engine cores and 11 full engines. Testing and rebuilds of the complete turbofan have been under way at Honda’s aircraft engine research-and-development center in Japan for more than 18 months.
This year, the 2,095-pound-thrust engine is to undergo flight tests on a flying testbed. The certification program is understood to also include tests on the HondaJet itself but it is unclear when this will happen. By service entry, the HF120 is expected to have accumulated some 15,000 hours of ground and flight testing.
HF120 engine production is to begin this year at GE’s Lynn, Massachusetts facility. Production will then transition to Honda’s new factory in Burlington, North Carolina, which is slated to open for engine deliveries in 2010. The GE Honda Aero Engines joint venture was formed in 2004.
The HF120’s fan is a bladed integrated disk (blisk) and has wide-chord, swept blades. The fan’s design was subject to competition between GE and Honda teams and the two proposed designs were eventually merged.
The two-stage booster is made of blisks, too. Downstream, it is followed by a single-stage centrifugal compressor. The impeller builds on Honda’s experience in developing turbochargers for racing cars.
The reverse-flow combustor features advanced materials for its laser-drilled multihole cooling arrangement. The single-stage high-pressure turbine has single-crystal blades that will help reach the 5,000-hour TBO target. The low-pressure turbine has two stages and its two spools are counter rotating.
The noise target for the new engine is “Stage 4 with margin.” The engine’s thrust falls below CAEP 6 compliance limits but GE (Booth No. 1063) and Honda (Booth No. 7021) still want to have emissions within extrapolated CAEP 6 numbers. As for fuel burn, GE Honda designers want it to be “better than that of same-class engines.”
GE Honda is promising that all components will be accessible for maintenance. Line replaceable units will be one-deep. The engine weighs less than 400 pounds and its bypass ratio is 2.9.
GE Working on GEnx-Based Core
General Electric has a core engine demonstration program that could form the basis for a 10,000-pound engine development. Dubbed eCore, it is a starting point for business, regional and narrowbody commercial jets, as a GE official put it. It covers quite a wide thrust range–10,000 to 20,000 pounds. GE’s CF34 replacement plan is code-named NG34 and is expected to use eCore technology.
The eCore builds “to a great degree” on that of the GEnx, which is to power the Boeing 787. Thanks to advanced materials (such as ceramic-matrix composites) and three-dimensional aerodynamics, the compressor’s pressure ratio is expected to be improved to 20:1.
The bottom line is targeted to be a 16-percent better fuel efficiency over GE’s best engines in operation. A time frame for NG 34 certification depends on aircraft makers but a GE official suggested that it could be ready in 2015.