by Matt Thurber
- October 29, 2016, 1:00 PM
Now that the first engine developed by the GE Honda Aero Engines joint venture is
powering dozens of in-service HondaJets, the new turbine engine manufacturer is
looking to the future, not only for the HF120, but new
engines that could grow into a family of powerplants.
Two
other companies had announced plans to use the HF120, but neither program has
advanced very far. Spectrum Aeronautical was the first to formally announce an
agreement with GE Honda Aero for an airplane powered by
the HF120–prior to the HondaJet–but
the company’s S.40 Freedom never made it into production. Earlier this year,
there were rumors about restarting the Freedom program, but so far nothing has
transpired. “There’s a glimmer of hope in [Spectrum founder] Linden Blue’s
eyes,” said GE Honda Aero president Steven
Shaknaitis. “He’s talking to the Mexican government about potentially building
in Mexico. We had committed to doing the engine on the S.40 if it ever
restarts.”
The
other program was the Sierra Industries Sapphire, a re-engining of the original
CitationJet, CJ1 or CJ1+ with the HF120.“We did some integration
work, and we have a hope of someday powering CitationJets,” he said. The HF120 has already flown on a CitationJet
testbed during engine testing, but according to Sierra’s new owner Innova
Aerospace, the Sapphire program will now use a different engine.
The HF120 grew out of the HF118 that Honda designed and built and that
powered the first proof-of-concept HondaJet. After the establishment of the
50-50 joint venture company, engineers from GE and Honda developed the more powerful
2,095-pound-thrust HF120, which has
a 5,000-hour TBO and no hot-section inspection event.
“The
state of the joint venture is very healthy,” Shaknaitis said. “One of the key
things we see is that the engine was designed by people who put commercial
engines in the air. It might have been over-designed, but it’s a hell of a
reliable engine with a high life limit.” As of early October, GE Honda Aero had delivered 120 engines.
There
are some key attributes that give the HondaJet its outstanding performance (max
cruise speed of more than 420 knots), and one that is significant is the HF120’s higher thrust at altitude.
This is due to the wide-chord blisk-type fan with 3-D compound swept blades
that enable a higher fan pressure ratio, according to the company.
The HF120 also features a high-pressure-ratio
core, which is facilitated by the design of the compressor and its titanium
alloy construction. This “enables the engine to minimize thrust loss during
climb,” thus helping the HondaJet climb quicker and cruise faster at the
mid-30s flight levels.
The HF120’s specific fuel consumption
is relatively low, and this is because of the laser-drilled multi-hole
combustor design, which “provides low pressure drop across the combustor and
efficiently transfers compressor energy to the turbine,” and air-blast fuel
nozzles providing better fuel atomization, which yields better fuel-to-air
combustion, according to the company.
The
unique over-the-wing-engine-mount scheme on the HondaJet does reduce vibration
and noise in the cabin, but aspects of the engine design also help with those
parameters. “A lot is due to our engine design,” said Daniel Harris, director
of marketing and programs for GE Honda Aero. “We put a lot of effort
into core and fan vibration, and we’ve got stringent standards that we agreed
to with Honda Aircraft.” Some initial production engines didn’t meet the
vibration standard due to the way the fan blisk was made, but that was fixed.
“We had to craft assembly processes so the engines stay within the vibration
limits for delivery,” he said. “You simply don’t hear and feel the engines.”
These
low noise and vibration characteristics, said Shaknaitis, “will translate to
fuselage-mounted engine too.”
With
its airliner engines, GE is famous for on-condition maintenance
programs where engines stay on the wing for tens of thousands of hours. While
that isn’t likely for a business jet, which doesn’t fly nearly as much as an
airliner, the HF120’s long 5,000-hour,
no-hot-section TBO also contributes to lower operating
costs. Design features that make the TBO so long include using super alloys to
manufacture turbine blades so they can run hotter and last longer.
Comprehensive engine monitoring is also an important factor.
“We are
getting to an on-condition kind of [situation],” Shaknaitis said. “We’re
looking at data to help the industry understand how you can get there. Taking
an engine off when you hit 4,999 hours, that’s not [efficient]. There’s so much
data, so many sensors…can you capture that and do something with it that will
benefit the owner?”
At its
Burlington, N.C., factory, he said, “We’ve got a really good team, a
state-of-the-art facility, and we’ve made tremendous gains coming up the
learning curve. We’re ready to double down with this joint venture. We have a
solid business, support infrastructure, spare engines, distribution centers,
and everything you need we have put in place. Now we’re ready for the next
step.”
That
step could include new engines developed by the joint venture company. “We want
to do another engine or two to serve other sectors in this business jet arena,”
Shaknaitis said. “We believe the sweet spot is a 3,000- to 4,000-pound thrust
engine. We are studying it, but we also need to have a home for it. We’re
talking to people and trying to collect market intelligence. The Phenom 300 is
the best-selling business jet now, and that’s the area we think is the place to
play. We’re looking at key characteristics and requirements for the next
engine, but we will not walk away from the best performance, quality and
5,000-hour TBO without a hot-section inspection.
That’s where we’re not going to compromise.”
Original post: ainonline.com
GE
Honda HF120
Image honda.com
Wide-chord blisk-type fan
Source honda.com
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