JAXA Aeronautics Magazine
Aeronautical
Technology
Directorate

2017

15/16

No.

Feature Stories
At the stage of delivering tangible results that benefit society

Challenge of the Next Generation Aeronautical Innovation Hub Center
The aFJR (Advanced Fan Jet Research) project

Taking aircraft engine development in a new directionJAXA Aeronautics Magazine

2 0 1 7 No .

3

15/16

Feature Story 1

At the stage of delivering tangible results that benefit society

Challenge of the Next Generation Aeronautical Innovation Hub Center[Related technology] Tactical lightning avoidance technology
8

Feature Story 2

The aFJR (Advanced Fan Jet Research) project

Taking aircraft engine development in a new direction[Related technology] The technologies of the aFJR Project15

PeopleTakeshi Fujiwara"Navigating activities for the certification of aviation equipment"

Yasuhiro Mizobuchi"To glean insight from simulation results, you need to understand the fundamentals of combustion phenomena."

17

Sky Frontier

Hydrogen-utilization technologies
18

Basic and fundamental technology

FaSTAR-Move: Analyzing the airflow around moving/deforming objects
Super-small turbofan engine technology
20

JAXA Aeronautics Symposium 2016

FLIGHT PATH No.15/16
JAXA Aeronautics Magazine
March 2017

Cover Image: Inside the cylindrical launch tube of
an impact resistance test device.
A gelatin ball, injected at a high speed, advances
through the launch tube and hits the target at theexit of the launch tube. In the very center of theimage is the test target, the leading edge (paintedblue) of a CFRP fan blade prototype.

Published by: Aeronautical Technology Directorate,
Japan Aerospace Exploration Agency(JAXA)
7-44-1 Jindaiji Higashi-machi, Chofu-shi, Tokyo 182-8522
Website: www.aero.jaxa.jp/eng/[All rights reserved] The contents of JAXA aeronautics magazine “FLIGHT PATH” may not be reproduced or
reprinted without prior permission from JAXA. For queries, please contact the JAXA Aeronautical Technology Directorate.

2

Leading edge

A CFRP fan blade prototype

Bringing together diverse human resources andtechnologies from a broad variety of fields, JAXA’s
Next Generation Aeronautical Innovation Hub Centertranscends the boundaries of industry, academia, andgovernment to fuel advances in aviation. Launched
in FY 2015, the Aeronautical Innovation Hub Center
facilitates open innovation and is now starting to
produce tangible results from its research activities.
This article introduces the scope and progress of theresearch activities at the Aeronautical Innovation HubCenter through an interview with Shigeya Watanabe,
Director of the Next Generation Aeronautical Innovation
Hub Center.

Shigeya Watanabe

Feature Story

Director
Next Generation Aeronautical Innovation Hub Center

Challenge of the Next Generation
Aeronautical Innovation Hub Center

At the stage of delivering tangible results that benefit society
WEATHER-Eye: Preventing aircraft
accidents caused by weather phenomena— Last year saw the launch of the WEATHEREye Consortium, in which members work together todevelop feasible technologies for preventing aircraft
accidents and delays attributed to weather—namely WEATHER-Eye (Weather-Endurance Aircraft
Technology to Hold, Evade and Recover by Eye). How
does that line of research fit into the AeronauticalInnovation Hub Center’s strategy?
Research and development activities at the AeronauticalInnovation Hub Center are managed under three basic policies:
addressing themes that can benefit society and industry;
driving “open innovation” to create innovation throughintegrated R&D with cross-sectoral and multidisciplinary
collaborations; and delivering high-impact results, eventuallygiving back to society through those outcomes.
The WEATHER-Eye Consortium perfectly fits with thosepolicies. The aeronautical Innovation Hub Center’s open
innovation framework helps incorporate a wider breadthof knowledge from areas outside aeronautics, which brings
about new ideas for better solutions in protecting aviationfrom weather disturbances. Plus, developed solutions makeaircraft safer while safeguarding operational efficiency, which
would make valuable contributions to society and industry.
— Specifically, which weather phenomena does
WEATHER-Eye Consortium deal with?
We’re focusing on technologies for ice and snow,

lightning, and volcanic ash. As for snow and ice, two
research initiatives are underway. The first one is the “snowand ice monitoring sensor technology.” Snowy runways cancause overrun accidents, diversions, and flight cancellation.
JAXA has been developing sensor technologies* thatenable the detection of runway snow and ice conditions inreal time through a partnership with a sensor manufacturer
and Kitami Institute of Technology. We are going to assess
the performance of the technology in outdoor settings thiswinter by embedding the sensor systems in the ground at
Kitami Institute of Technology in Hokkaido, Japan.
— What about the scenario after the evaluationof performance?
Once the ground evaluation has demonstrated thefeasibility and effectiveness of the sensor technology, we’ll
start receiving more detailed and specific demands fromthe prospective users: airlines, airports, and the Ministryof Land, Infrastructure, Transport and Tourism (MLIT), forexample. Users’ voices will help us improve technology
to make fur ther steps for ward toward launchingdemonstrations on public roads in FY2018 and, eventually,on actual runways. Being able to work toward a common
goal with users means a lot. Although it might create some
added pressure, having users on board in the consortium
allows us to gather valuable feedback and keep ourinnovations on course for society-wide implementation.
— Airlines must be excited about this technology,
which would help them greatly.
They definitely are—and we’re determined to deliver

what they’re looking for. Another driver is the plannedchanges to the international regulations on the runway
surface condition assessment, measurement, and reporting,which are going to go into effect in November 2020. In
the conventional approach, the friction coefficient of atarget runway is measured and then provided to passenger
aircraft pilots, but the figures don’t always match theactual runway surface conditions when the pilots maketheir landings. That’s why there’s a need to classify runway
surface conditions from a more comprehensive standpoint,
one that includes snow and ice type, depth, ambient
temperature, and other key indicators instead of just thefriction coefficient. The key is choosing the right typesof information to base that classification on. Our sensor
system can provide those types of data, which would help
the MLIT set Japan-specific grading according to the newinternational regulation.

Accelerating R&D— What’s the other part of the research on snow
and ice?
The other piece is an “airframe anti/de-icing technology.”
Icing degrades the overall performances of aircraft,
triggering causes of accidents. JAXA has been studying
a hybrid ice protection system that combines an icephobic coating and an electro-thermal heater. The initial
phase of the research was carried out under the EU-Japanframework project named JEDI-ACE (Japanese-European
De-Icing Aircraft Collaborative Exploration). Hoping to turn

* A snow and ice monitoring sensor, which enables real-time monitoring of runway surface conditions such as snow accumulation and slipperiness; see FLIGHT PATH No. 11/12 for details.

3that technology into a viable Japanese product, the second
phase of the research on the hybrid icing-protection
system is underway at the WEATHER-Eye Consortium.
— How's the progress on the hybrid ice protection
system?
We’ve been working with Fuji Heavy Industries Ltd. todevelop ice-phobic coatings. Currently, we’re examining
several types of the coatings that we’ve come up withrespectively—the JAXA coating and the Fuji Heavy
Industries coating—by applying them on to the airframeof JAXA’s Hisho research aircraft. To monitor and check if
the coatings experience any deterioration due to sunlight
exposure or the low-temperature and low-pressure
environments that characterize real flight conditions, theexperiment will continue throughout FY2018. Meanwhile, by
the end of March 2017, we’re going to perform experiments
on a small-scale hybrid system using the icing wind tunnel
at the Kanagawa Institute of Technology. Our plan forthe year 2017 also includes a performance evaluation of a
prototype system using a larger icing wind tunnel in the
United States that can simulate conditions close to in-flightatmospheric icing. As we continue gathering sets of data to
examine the feasibility of the technology, I’m confident that
we’ll be securely on our way toward a social contribution. I’m
excited about the prospects.
— That sounds like a fast-track eﬀort.
The “snow and ice monitoring sensors technology” and“airframe anti/de-icing technology” are two of the fastestmoving parts of the WEATHER-Eye Consortium. We’ll haveto do a lot more to deliver practical results to users aheadof international competitors.

The importance of understanding needs— What about lightning?

Our lightning-related efforts include two types ofapproaches. One is the “tactical lightning avoidancetechnology,” which makes it possible to detect lightning
hazard area in advance, and the other is the “anti-lightningtechnology,” which mitigates the damage to airframes
when they experience lightning strikes.
For “tactical lightning avoidance technology,” JAXA is
collaborating with the Meteorological Research Institute(MRI) to gather lightning-specific meteorological datafrom MRI’s weather radar and a lightning-monitoring
systems.
The coastline along the Sea of Japan tends to experience“winter lightning,” while the Pacific coast sees considerable
amounts of lightning in the summer. To accumulatea sizable amount of data, a series of meteorologicalobservations is underway at several places prone to thosephenomena—at Shonai Airport (located on the Japan Seaside) in the winters of 2016 and 2017, and at some places in
the Kanto region in the summers of 2016 and 2017.
In parallel, we are making collaborative efforts with
the MRI in developing software that uses algorithms todetect lightning hazardous areas in advance to estimate
which kinds of meteorological conditions are likely totrigger lightning strikes to airplanes. If we can develop a
viable solution for forecasting lightning strikes, passenger
aircraft will be able to avoid hazardous areas more easily.
—How about research on volcanic ash?
Japan is home to numerous volcanoes, and airlines
are sensitive about volcanic eruptions because they cancause severe damage to aircraft and operations. Especially,
engines can suffer severe damage if they ingest too much
volcanic ash, and, needless to say, the simplest and mostfundamental measure is to avoid volcanic clouds. There’dbeen very little research into volcanic ash at JAXA until weConventional system

The sensor is embedded here

The snow and ice monitoring sensor installed at Kitami Institute ofTechnology (Top: Construction in progress; Bottom: Installation site)

got into discussions about the WEATHER-Eye Consortiumand started seeing how important the issue was. For our
first step, we’re now looking into simulation technology tohelp elucidate what might happen inside the engine when
it ingests volcanic ash.
— It sounds like user needs are the driving
forces behind the research at the WEATHER-Eye
Consortium.
That’s the distinctive feature of the WEATHER-Eye
Consortium. Users obviously won’t be able to utilize
technologies or products that aren’t useful to them. That’s
why we’re building our effort as much as possible aroundreal and practical needs.
— Do you think the WEATHER-Eye Consortium isgoing to make a big impact?
I believe so. I already see a positive effect of open
innovation. We’re charting a much straighter course toward

Hybrid ice protection system
Secondary icing

Hot
air
duct

Leading edgeof the wing

Ice protection via bleed air
from the engine

Electric heater

Ice-phobic
coating
Electro-thermal
heaterArea applied with
ice-phobic coating

Supercooled
water droplets

Heating area

Ice-phobic
coating area
Heating area withelectro-thermal
heaterAir flow with water droplets

Electric heater-type ice protection

4

Preventing secondary icing with
ice-phobic coating

On-board system configuration

Applying a riblet coating to an actual-size aircraft
mockup (joint research with Tokyo Metropolitan
University; the red rectangle corresponds to thecoating area)

Challenge of the Next Generation Aeronautical Innovation Hub Centersocial implementation than the path in a conventional R&D
approach in JAXA.

Eco-Wing technology: Reducing theburden on the environment— What other research are you working on besides
WEATHER-Eye?
We have the “Eco-Wing” initiative, which focuses ondeveloping aviation technologies that reduce aircraft’s
environmental load by improving fuel efficiency, cutting
down on CO2 emissions, and reducing noise levels. I thinkit’s the area where open innovation should play a majorrole in developing practical solutions.
Here, let me introduce two research activities under
the Eco-Wing initiative. The first one is our “Flight
Investigation of skiN friction-reducing Eco-coating (FINE).”
Reducing air-induced skin friction on aircraft surfaces
boosts fuel efficiency, and researchers have found that
there are several effective ways to do that: You can coatthe surface of an airframe with a “riblet” pattern ofultra-fine streamwise grooves, for example, or cover theairframe with a sheet of such grooves. JAXA has studied
the riblet height and angle, investigated optimal riblet
configurations, and even applied for a patent. The big
issue for realizing the riblet is that knowing the ideal riblet
configuration doesn’t do much good if you can’t actually
apply it on an airframe—a step that requires the help ofa specialist in coating methods. That’s where the openinnovation approach of the Aeronautical Innovation HubCenter comes in, making it easier to get over that barrier
and create real, practical solutions for society at large. We
want to give manufacturers and users tangible results asfast as we can, so our plan for 2017 and 2018 is to use theeco-coating on "Hisho" and get some flight data on thedrag reductions.
The other research that can really benefit from open
innovation is our “High performance Optical fiber sensor
flight Tests for AirpLane Wing (HOTALW),” which centers ontechnology for measuring aircraft wing deformation. We
just completed our first HOTALW flight test in November
2016, actually. Aircraft wings have to be designed under adelicate balancing methodology: A wing naturally bends
due to aerodynamic force, but erring on the side of caution
and making the wing too strong can lead to increased
weight and inefficient fuel usage. To design the optimal
wing, then, manufacturers need to have a good grasp of
how much the wing deforms. That knowledge makes it
possible to develop thin, light wings capable of adapting

to situations where sudden gusts of wind create
increases in aerodynamic load. For our research,
we use optical fibers on the wing surface todetermine the distribution of the deformationthat the wing experiences—and that process,once again, involves drawing on assistance fromoutside the aviation sector. Our open-innovation approachhas enabled us to work with a sensor manufacturer
that boasts expertise in what we’re looking for, thereby
facilitating the overall effort.

Technologies for aircraft component
certification: A crucial area for theJapanese aircraft industry—Another point we’d like to hear your thoughts
on is your research for securing aircraft component
certification, an area where the AeronauticalInnovation Hub Center seems to start devoting a lotof energy.
Japanese aircraft component manufacturers boast
a wealth of sophisticated technologies, but getting
their products into actual aircraft entails obtaining
official certification—a step requiring an environment
for certification that few small- and medium-sizedindividual manufacturers have access to. For component
manufacturers, that’s a huge roadblock. To help companies
clear that hurdle, we’re going to keep developing software
libraries and other resources for companies to use on ashared, common basis. The challenges of the certification
process go beyond technological resources, too: It’s hardto navigate all the complicated procedures without a solidbase of experience. By working together with component
manufacturers, pooling together valuable experience,and sharing that insight with members of the component
manufacturer community in Japan, JAXA can lower thethreshold to successful certification.
—And that’s JAXA’s responsibility.
Yes—and it’s something that the AeronauticalInnovation Hub Center allows us to do. The certification
process hadn’t been a part of JAXA’s research agenda
until the Aeronautical Innovation Hub Center took shape.

Considering what the center should do, I knew thatcertification could be a great area to venture into. To boost
overall sales and keep performance climbing, the Japaneseaircraft industry needs component manufacturers to
expand their businesses.

Forward-looking technologies in longterm R&D— What other kinds of research efforts are you
hoping to see at the Aeronautical Innovation HubCenter?
I want to keep tackling technologies with a focus on
the long-term future. Emission-free aircraft technology,
for example, is something we might be able to do years
and years down the road. Imagine the breakthroughthat we could achieve if we succeeded in making aircraftcompletely electric and capable of running on renewableenergy—we’d have access to amazing, emission-free
air transportation. For these kinds of forward-looking
initiatives with the potential for significant social impact,
we’re going to rely heavily on open innovation with players
from other fields to get the cutting-edge technologies
we’re looking for. Future-oriented technologies likeemission-free aircraft are exactly what we envisioned
when we made delivering “high-impact” results one of ourthree policies.
— What are your hopes and goals for the future?
It’s important for the Next Generation AeronauticalInnovation Hub Center to produce a steady stream oftangible output, in particular, from FY2016 onward. As
we start producing tangible results, I’m sure we’ll startseeing new needs emerge. Likewise, as we bring in newtechnologies from other fields, we’ll be able to do things
we’ve never been able to do. We at the AeronauticalInnovation Hub Center can really make a real difference if
we keep those types of activities growing—and producing
results that benefit the world. That’s the kind of positive,
virtuous cycle we’re aiming for.
http://www.aero.jaxa.jp/eng/
about/hub/index.html

Airlines

Manufacturers

Universities

All Nippon Airways Co., Ltd.
JAL Engineering Co., Ltd.
Japan Airlines Co., Ltd.

Fuji Heavy Industries Ltd.
Nihon Tokushu Toryo Co., Ltd.
Sentencia Corporation

Kanagawa Institute of Technology
Kansai University
Kitami Institute of Technology
Nagoya University National Composites Center
Osaka University
Tokyo University of Agriculture and Technology
Tokyo University of Science
University of Tokyo
Yamagata University

Public research institutions
Civil Engineering Research Institute for Cold Region(CERI)
Japan Aerospace Exploration Agency(JAXA)
Meteorological Research Institute(MRI)

18 member organizations of the WEATHER-Eye Consortium(6 companies, 3 research institutions, and 9 universities)

5

Improving air safety with open innovation approach

The WEATHER-Eye Consortium
By incorporating diverse knowledge and insights across disciplines and sectors, the WEATHER-Eye Consortium aims at developing
integrated and practical solutions to protect aircraft from weather issues such as snow, ice, lightning, and volcanic ash.

Protecting aircraft from special weather conditions

The WEATHER-Eye Open ForumJAXA promotes open innovation, encouraging the flexible use of knowledge fromThe Consortium presented its future vision at the “1st WEATHER-Eye Open Forum:

outside the aeronautics field to tackle research themes at the Next Generation AeronauticalProtecting aviation from special weather conditions (snow, ice, lightning, and volcanic

Innovation Hub Center. An example of JAXA’s strategic approach to open innovation is theash),” held at the University of Tokyo’s Takeda Hall on September 27, 2016.

WEATHER-Eye technology.

Comprising of two parts, the Open Forum aimed to help identifying new partners for

Aircraft accidents often involve weather-related factors, including sudden airflow

aiding in the problem-solving process and locating latent and more diverse user needs.

changes like wind shear and microbursts. Meteorological conditions have a substantial

The first part introduced the WEATHER-Eye Consortium’s vision and addressed theimpact on aircraft operating efficiency, as well: Airframe icing can result in delayed

expectations of user representatives from the public and private sectors. Norio Okada fromtakeoffs, while runway snow can cause cancellations and diversions. Lightning strikes

the Japan Civil Aviation Bureau explored the possible benefits from the regulatory side,

also cause more damage to composite airframes than conventional metallic airframes,

speaking on behalf of Japan’s civil aviation authority, while Masami Ichikawa from therequiring longer repair times to fix. Minimizing and avoiding the effects of weather

Japan Airlines Co., Ltd. addressed weather-related technologies from a pilot’s perspective.

would thus not only enhance aircraft safety but also improve overall aircraft operational

The second part included a series of presentations that introduced ongoing research efforts

efficiency.

to develop solutions corresponding to various weather-related factors (see below).

To enable an integral and open approach in developing the WEATHER-Eye technology,

The Open Forum successfully drew even wider attention from various fields, including

the WEATHER-Eye Consortium was launched on January 15, 2016, upon the agreement of

information, communications, architecture, engineering, and electricity. The ideas

18 member organizations.

exchanged at the Open Forum will be incorporated into the discussion at the WEATHER-Eye
Consortium to create even better outcomes that benefit both industry and society at large.

Creating a shared vision to work toward a common goal
The WEATHER-Eye Consortium brings together a wide variety of knowledge and ideas
across fields and sectors, including airlines, manufacturers, weather-related organizations,and civil engineering institutions. To share the same vision for the future, the Consortium
has compiled a list of problems that occur under special weather conditions, evaluated thecorresponding risks, and used the results to lay out key themes (see the Table below). The
members have also formulated a road map for short-term (3- to 5-year), medium-term(10-year) and long-term (roughly 20-year) goals, moving from technological developmentin the near future to technological demonstration and, ultimately, social implementation.
Through the process, the members have also reaffirmed that efforts to develop the
WEATHER-Eye technology will be instrumental in helping Japan’s aircraft-related industries

The WEATHER-Eye Open Forum: lectures and presentations■ Preventing overrun accidents caused by snow accumulation
Hirokazu Ohmae (Sentencia Corporation)■ Ensuring safety through icing-prevention measures
Takeshi Yoshida (Fuji Heavy Industries Ltd. Aerospace Company)■ Preventing accidents caused by turbulence
Naoki Matayoshi (JAXA Aeronautical Technology Directorate)■ Mitigating the risks of lightning strikes
Ken’ichi Kusunoki (Meteorological Research Institute of the Japan Meteorological Agency)■ Safeguarding against airframe damage caused by lightning strikes
Tomohiro Yokozeki (The University of Tokyo School of Engineering)■ Protecting engines from ingesting debris (ice crystals, volcanic ash, and more)
Shigeru Tachibana (JAXA Aeronautical Technology Directorate)

sharpen their competitive edges.

Key themes for the WEATHER-Eye Consortium
Phenomenon
Runway snow/ice

Flight cancellations and overrun accidents, etc.

Airframe icing

Loss of lift and increased fuel consumption, etc.

Turbulence

Reduced flight control, etc.

Low-level wind shear

Reduced flight control, etc.

Lightning strikes
Ice crystal ingestion
Supercooled water droplet ingestion
Fog
Cosmic rays

6

Resulting problems

Structural damage, etc.
Sensor malfunctions and loss of thrust, etc.
Internal damage and loss of thrust, etc.
Flight delays and cancellations, etc.
Disabled equipment, etc.

Attended by 184 participants from a diverse mix of fields, the WEATHER-Eye Open Forum stimulated lively discussions
among presenters and participants.

Multi-sensor observation

Feature Story

Related Technology

Technology for detecting lightning-hazard areas and estimating potential risks

Tactical lightning
avoidance technology

JAXA’s research on tactical lightning avoidance technology focuses primarily on
feasibility studies of an airport-based support system that provides taking-off orlanding aircraft with lightning avoidance information. Eiichi Yoshikawa, researcher at
the Next Generation Aeronautical Innovation Hub Center, provides an overview anddiscusses the challenges of the tactical lightning avoidance technology, which forms apart of the WEATHER-Eye initiative.

How lightning affects aircraft operations
Everyone knows what lightning looks and feels like: a flashof light bolts through the sky as a rumble of thunder rattles theair. A bolt of lightning is more than just a visual and aural jolt,
however—the energy of a lightning strike is also powerfulenough to split a tree in two. Lightning is an electrical discharge
phenomenon that occurs because of an electric potential
difference. When ice particles in a cloud (hail and crystals)
collide, those particles are electrically charged, and the cloud
takes on positive and negative charges. When the charge
amount exceeds a certain threshold, a lightning discharge
occurs. Although most people probably assume that a bolt oflightning always extends downward from a cloud until it reaches
the ground, most lightning occurs entirely inside clouds—andsome can even strike airplanes.
An aircraft in the en-route phase can easily adjust its flightpath to keep sufficient distance from thunder clouds and avoid
lightning strikes. Even if the aircraft suffers a lightning strike,the event almost never causes a fatal accident because aircraft
are designed and built with strict certifications for lightning
endurance—but the phenomenon can be more challenging todeal with in other phases. “It’s harder to avoid thunderstorms
during takeoff and landing phases, first of all,” Yoshikawa
explains. “Even though a lightning strike may never be the directcause of an accident, the resulting damage still creates the needfor repairs that can hamper aircraft operations.”
Until very recently, research on the relationships between
lightning and aircraft attracted minimal attention among the
global community. Not only did observation equipment lackthe high-resolution capabilities to gather detailed readingsof thunderclouds, but the fact that lightning never directly
triggered a significant incident in civil aviation relegated thephenomenon to a relatively low profile in research circles.
However, the circumstances have been changing along with
the increase in the use of composite materials in aircraft. A
lightning strike can have a powerful impact on composite
materials, making the repair process much more timeconsuming for a composite material-based aircraft than it isfor a standard metallic unit. To ensure efficient operations,aircraft need to avoid lightning strikes wherever possible.

Taking-oﬀ aircraft

Landing aircraft

Path selection

Path selection

Timing decision

Timing decision
Holding-area selection

Lightning risk estimation
Integrated data processing/information transmission

through FY2015, JAXA has long been gathering input onaircraft lightning strikes from relevant parties such as airlines,
manufacturers, universities, other research institutes, theMinistry of Land, Infrastructure, Transport and Tourism Civil
Aviation Bureau, the Japan Meteorological Agency, andother sources. To turn that base of knowledge into a tangible
technology, JAXA has decided to launch a research initiative
named “tactical lightning avoidance technology” beginningin FY2017. With this initiative, we are going to develop an
airport-based support system that detects lightning-hazard
areas and estimates potential risks.
The tactical lightning avoidance technology is basedon a three-party collaboration of JAXA, the MeteorologicalResearch Institute (MRI), and the Electronic Navigation
Research Institute (ENRI). The MRI offers high-level knowledge
pertaining to atmospheric phenomena of all kinds, including
lightning discharge. What JAXA brings to the table, meanwhile,is its expertise in evaluating how discharge phenomena affectairframes and flight. Completing the collaborative structure
is ENRI, which is adept at assessing the effects of weather onaircraft operations. By gathering their resources, the threepartners have what it takes to address the issue of aircraft
lightning strikes from a comprehensive, integrated standpoint.
JAXA is planning to expand the collaborative arrangement
beyond the MRI and ENRI, as well, intending to get multiple
universities on board as the project moves forward. For
FY2017, the plan is to determine the feasibility of the target
technologies. Although the research effort is just getting off
the ground, the ultimate goal is clear: create a system that
integrates a wide variety of meteorological data, displays
lightning information on a map-based interface, and gives

Probability

users a clear, intuitive picture of potential lightning hotspots
without the need for any special technical knowledge.

Refining Japan's unique technology

In Japanese, lightning also goes by the name of inazuma,
a kanji compound that contains the character for “rice plant”(ina). The word is said to be derived from the fact that lightning
is most common during the period when rice plants are inbloom (summer to fall), but lightning can occur during otherseasons. “Winter lightning,” for example, is a relatively rare
phenomenon that occurs in just two areas in the entire world:
the Sea of Japan coastline and a portion of the Norwegiancoastline. Bursting with energy 20 to 100 times more powerfulthan normal summer lightning, winter lightning is thus a much
more potent threat to aircraft. That makes the ability to locate
lightning-prone areas particularly important in locations where
winter lightning occurs; as Yoshikawa explains, “JAXA’s lightning
detection system would definitely be a big help for airports
along the Sea of Japan.”
Although researchers abroad are also working on tactical
weather support, most of the projects focus on detecting rain
and clouds (for storms)—not the occurrence of lightning itself.
Even if the aircraft avoids cumulonimbus clouds, it can still
experience lightning strikes. Researchers are already awarethat aircraft-initiated lightning is a frequent occurrence—and
JAXA’s efforts will have to take those types of conditions into
careful consideration. The process of gathering massive volumesof data, analyzing the findings, and building a reliable system
will obviously be a challenge. If we can clear those hurdles
and develop feasible results, we will be able to showcase andcultivate the technology as a unique Japanese achievement.

ImpactRisk

Collaboration beyond aeronautics

JAXA has been addressing aviation weather information
technology. Although lighting has not been part of past
research initiatives such as the DREAMS Project, which ran

A conceptualization of the lightning weather information interface; “impact” refers to the potential intensity of a lightning strike or potential damage to the aircraft.

7

JAXA’s aFJR (Advanced Fan Jet Research) project isabout to deliver tangible results for both the fan andlow pressure turbine components as the team gears
up with industry players for its final demonstration
tests in FY 2 0 17. This article introduces a special talkon the latest project progress.
Special talkKuniyuki Imanari

Toshio Nishizawa

IHI Corporation

JAXA

Feature Story

Kuniyuki Imanari (IHI) (Left), stands with Toshio Nishizawa(JAXA) (Right)
in front of the RJ 5 0 0 engine

The aFJR (Advanced Fan Jet Research) project

Taking aircraft engine development in a new direction
Japan’s high-bypass-ratio engine
development began with the FJR710— Let’s take a look back at how jet-engine
development evolved up to the aFJR project. Was
the FJR710 the first step?
Nishizawa: It was. The FJR710 was a project by METI,
the Ministry of Economy, Trade and Industry (then MITI,
the Ministry of International Trade and Industry), and it
marked Japan’s first foray into developing high-bypassratio engines. The government invested a substantial
budget into the project, which produced an engine that
we eventually installed on the “Asuka”*1 experimental
STOL aircraft for flight tests. Through these initiatives,
many engine-testing facilities were built at JAXA (then theNAL), and the engine industry really started to grow. The
FJR710 paved the way for Japanese manufacturers to get
involved in the international project to develop the V2500.
Imanari: The V2500 is nearing the end of its run, with a newengine model set to take its place, but it had an impressive,
best-selling track record with sales of over 7,000 units.

Nishizawa: That’s a pretty amazing number, isn’t it? The
V2500 hit the market in the late 1980s, which means thatit took about 20 years to develop after the FJR710 project
got going in 1971.
Imanari: That’s generally how it goes in the aircraft
engine world. You normally have to put 20 years of
R&D into a project before it produces an actual engine.
Technological development starts to hit full gear about
10 years into the project, with engine development only
getting off the ground about 15 years after the launch of
initial research. Basically, you need to have good, viable
technology—something that people can see promise
in—a decade in advance. To get to the point where you
have advanced, globally competitive technologies a full
10 years before the final product takes shape, you have to
get the research process started 20 years out. That gives
you enough time to push things far enough forward andsteer the project through any complications.
Nishizawa: I don’t know how clearly the FJR710 teamwas envisioning the V2500 market when the project got
started, but one thing’s for sure: The timing was great.
Imanari: After the FJR710 performed extremely wellduring its test operations in the UK, Rolls-Royce cameforward with an offer to work on the engine together.
That laid the groundwork for the RJ500 project, which
later expanded to include collaborators in five countries
and become the V2500 development project. Once theV2500 was ready, Airbus signed on to install the engine.
Japan was lucky to be part of that joint-development
initiative—and without the FJR710, I don’t think thatluck would’ve ever come around.
— So the team wasn’t actually aiming toinstall the FJR710 on Asuka?
Nishizawa: Not as far as I know. The FJR710 was a MITI
project, but Asuka was an initiative at the Science andTechnology Agency—an NAL-led effort. The Asuka teamprobably had other engine options, I imagine, but they
ended up installing the FJR710 and using it for flightdemonstrations. That was a big step for Japanese engine
development.

The advent ofsupercomputer-based simulations— JAXA continued to press forward withresearch on the METI-led HYPR and ESPR engines
projects for supersonic transport. Did the FJR710
development initiative have an impact on thoseefforts?
Nishizawa: The HYPR and ESPR engines look different
from the FJR710 because of their different target speeds(Mach 5 and Mach 3, respectively), but they both utilize
technologies that came out of the FJR710 project. When
work began on the HYPR and ESPR, JAXA was just getting
started with supercomputer-based engine simulation—
something that didn’t exist during the FJR710 initiative.
I think the HYPR and ESPR came along right aroundthe time when simulations were occupying bigger andbigger roles in what we were doing.
Imanari: Around the time of the HYPR project, we wereactually working under joint-development arrangementswith some foreign manufacturers. When they saw theKuniyuki Imanari
8

Deputy Division Director
Research & Engineering Division
Aero-Engine & Space Operations
IHI Corporation*1 A short take-off and landing (STOL) experimental aircraft developed based on the C-1 transport
aircraft; equipped with four FJR710 engines, the aircraft completed 97 flight tests from 1985 to 1989.

The history of JAXA’s aircraft engine development

2010

2000

calculations from the NAL supercomputer, which wewere using at the time, they couldn’t believe how fast wewere coming up with our results. Those manufacturers
were world-class firms, too—and even they couldn’t
keep up. Japan was a cut above the rest when it came tocomputational fluid dynamics (CFD).
Nishizawa: At the time, the NAL supercomputer wasconsistently at the top of the world benchmark rankings.
That resource gave researchers what they needed to dosome really challenging, high-level work.
Imanari: We’re still using JAXA’s CFD software for ourdesign efforts. The low-pressure compressor for the
successor to the V2500 engine was one example. In
the new “geared turbofan” engine type, there’s areduction gear between the fan blades and the lowpressure compressor. To make sure that the gear in theengine moves smoothly, you have to supply and drain
oil through the frame. The lubricant—hot oil—flows
through the frame near the compressor’s upstream
sector. In designing the engine, we needed to figure out
how the heat transfer from the frame to the mainstream
would affect engine performance. That’s where JAXA’stechnology came in, allowing us to simulate theconditions and do a quantitative assessment of theresulting impact. Without that capability, the process
would’ve been much more challenging.
Nishizawa: Simulation technology is extremely valuable
when you’re dealing with special conditions that makeelement tests hard to do.
— The eco-engine research project came along
after that.
Imanari: The eco-engine was another METI project
where manufacturers got to pursue their own ideas fordifferent parts. For the combustor, though, there were
three companies vying for the spot. We had to makea competitive proposal, and we decided to use JAXA
facilities for our testing procedures. When I think backabout the connections between IHI and JAXA during theeco-engine project, that’s what I remember most.
Nishizawa: The project didn’t produce an actual
engine in the end, but it was instrumental in bringing
existing technologies into the new millennium. TheaFJR project
Asuka,
the experimental
STOL aircraft

1990
HYPR project
ESPR project

1980
V2500 engine
Image: JAEC1970

The FJR710 jet engine,
developed as Japan’s first-everturbo fan engine

low-pressure system at the heart of the aFJR initiative,
for example, wouldn’t have been possible without the
fan and simulation technologies that came out of theeco-engine project. That basis let us take the next step
forward—and that’s a pattern of progress that depends
on programs for passing technologies along.

Today’s R&D make tomorrow’s aircraft
engines possible— Why is JAXA working on the aFJR project
now?
Nishizawa: We’re targeting a small-sized aircraft for
150-passengers—a type that has a big share of today’s
aircraft market. We estimate that airlines are going to be
switching over to new fleets between 2025 and 2030. For
Japan to develop competitive technologies in the runup to that transition, we figured that we’d have to launch
the effort now. As we got talking with manufacturers, we
identified some target technology areas: low-pressure
system consisted of fans and low-pressure turbines. Our
meetings with different players in the manufacturingindustry helped us identify solid candidates and narrow
the field down to a smaller group of research elements.
— Does JAXA’s approach fit with the market
outlook from a manufacturer’s point of view?
Imanari: It sounds about right to me, yes. Assumingthat the transition is going to happen between 2025
and 2030, you’d need to give yourself 10 years for frontloading—which would mean starting now. Lowpressure systems are IHI’s biggest strong suit at the
moment, so we started thinking about how to get acompetitive edge in that arena. We eventually decided

to focus on composite materials: carbon fiber-reinforced
plastics (CFRP) for fans and ceramic matrix composites(CMC)*2 for low-pressure turbines. Another component
that we wanted to concentrate on was the metal “disk,”
the circular part that supports the fan blades. Developing
a good disk requires solid all-around technologicalcapabilities, especially considering that fan disk failures
can cause serious problems. When we were working on
the V2500, we didn’t have the kind of technical prowess
we needed. That shortcoming got to me, I guess; I knew
I wouldn’t feel comfortable until we could do the jobright ourselves. Then this project came along, giving us
the perfect opportunity to get where we had to be todesign and manufacture the metal disks on our own.
By focusing on composite materials and integrating
things like aerodynamic, structural, and noise-reduction
technologies, we wanted to put ourselves in position to
make our fan modules more competitive in the market.
— It’s important project for IHI.
Imanari: It is. Increasing the high bypass ratio leads
to a larger fan diameter in a turbofan engine, but
it also adds to the overall weight. That makes CFRP,
which boasts impressive strength levels in lightweight
configurations, an ideal material. Composite materials
are where IHI excels—we successfully used composite
materials for the fan exit structural guide vane and fan casingof the PW1100G-JM engine, an achievement that put us incharge of designing and manufacturing those components.
The fan blades are still metallic, and that just gives IHI
another target to shoot for. We’ve got our sights set on
making CFRP blades a reality as soon as we can. That last

An overview of the aFJR project
Global warming, the depletion of oil reserves, and other problems have led to stricter global environmental standards
in many fields, and the aviation sector is no exception. Aircraft engines, for example, now need to deliver improved fuelefficiency, reduce CO 2 and NOx emissions, and limit engine noise levels. Through the development of next-generation engine
technologies, JAXA is aiming to help reduce the environmental impact of future aircraft—and the aFJR project is one part ofthat mission.
The goal of the aFJR project is to develop and demonstrate technologies that can enhance the environmental compatibility offans and low-pressure turbines. Japanese manufacturers have extensive experience in these two components. The team will
aim for a technical level that can help Japan spearhead the design portions of joint international development projects fornext-generation aircraft engines. To achieve that goal, the aFJR project is a collaborative effort, with IHI as an industry player
and universities from academia playing important roles.

Toshio Nishizawa*2 Lighter than metal, resistant to heat, and resistant to oxidation, CMC material also includes
ceramic fibers that help prevent cracking. See FLIGHT PATH No. 9/10 for more information.

Project Manager
aFJR Project Team
JAXA

9

piece of the puzzle is the metal disk. If we can handle
the disk, we’ll be able to design every element of our fan
module.
Nishizawa: Disks are “life-limited parts,” which means thatthey have to be replaced after a certain amount ofservice time. The potential for profitable returns isthere, obviously, considering that disks will continue
to generate revenues through maintenance work afterusers purchase engines. In that sense, disks can help
expand the scale of the industry.

Taking advantage of the synergy
between JAXA and the manufacturingsector— Are materials the central focus of the aFJR
effort, then?
Nishizawa: Yes. In terms of the fan, IHI is handling the CFRP
material development, and manufacturers are alreadydoing work on the fan blade molds. The task for the aFJR
project team is to find ways of making the designs hollow.
For the disk, meanwhile, the effort is going to focus on
researching the trade-off between lightweight designs
and lifespan. JAXA’s in charge of getting the component
into proper position for manufacturers, who will then add
in extra features to get the design ready for the market.
It’s a collaborative arrangement between JAXA and the
manufacturing sector, one that can help the product reap
the benefits of synergy. Our effort is paying attention totrends abroad, too.
— Besides materials, what are the other key
technological features of the aFJR project?
Imanari: When you’re dealing with high bypass ratios
in this class, you can laminarize the fan flow to boost
efficiency. That’s exactly what we’re doing for thisproject. We’ve managed to show just how much ofa positive effect laminarization can have. From myperspective, it’s really important output.
Another one of our breakthroughs has to do with“flutter,” a type of vibration phenomenon that people
normally associate with fans. Theoretically, turbines
are also susceptible to flutter. We take steps to makesure flutter doesn’t happen, but the phenomenon getsharder to deal with in lighter designs—the lighter yougo, the more flutter you see. That’s where JAXA’s CFD
proved useful once again, allowing us to identify the
optimal countermeasures. The aFJR turbine also uses
CMC, an innovative new material. The only problem withusing a new material is that there’s no available data on
it. With CFD, we had a great solution for making better
predictions of how flutter would happen. It was amazing
how accurate the results were, especially compared towhere they used to be. I think we can be pretty proud ofthat progress. We’re definitely on a competitive playing
field with Europe and the United States now.
Nishizawa: The goal of predicting flutter with simulation

10

technology led the project team down an unconventional
path. We ended up using the altitude test facility,
designed for a totally different purpose, as a wind tunnel
for assessing turbine flutter. That transformed the test
setup into a kind of demonstration facility, giving thesimulations an even higher level of reliability.
— Where is the aFJR project at right now, interms of overall progress?
Nishizawa: We’re doing our final demonstrations foreach element. In early 2016, we finished validating
the foundations for the technologies that we need toincorporate into the prototypes for demonstration.
The stage we’re at right now involves designing each
prototype, one by one. JAXA’s done reviewing thedesigns for around 80% of the target components, whichmeans that we’ve started prototyping those pieces.
The design process for the remaining 20% is going towrap up by the end of FY2016. After that, we’ll test thevalidity of the developed prototypes and then go step bystep through the final tests during FY2017. That’ll bringeverything together at the end of 2017. We’ll do our final
evaluations to determine how the improvements in fan
and low-pressure turbine performance can boost thefuel efficiency of the complete engine. Right now, we’rebasically a step away from finishing the project off.
— How has the experience been for IHI?
Imanari: In a word, great. The project has been sucha valuable experience. The tough thing about aircraft
engine development is that you only get one chance ever
20 years or so. Timing is important. You need to makeeverything line up right in the end. Putting all your eggs
in one basket isn’t the only approach, though. There’s
always the potential for using the output of the project
in upgrades to the current engines. That’s another thing
we try to keep in mind. I think we’re almost ready topounce on any opportunity to use what we’ve come up
with. With long-term research on one side and shortterm applications on the other, we’re hoping to maintaina dual stance on making the most of our efforts.

An F7 engine as an engine test bed— JAXA is going to introduce a new engine test
bed, an F7-10 engine.
Nishizawa: The F7-10 engine is the 100% made-in-Japanturbofan engine that the Acquisition, Technology &Logistics Agency developed. It will take demonstrations
to the next level and help sharpen the competitive edgeof Japan’s engine component technologies.
Imanari: When you work with the major engine
manufacturers in the global market, they tend to
propose joint-development projects if the collaboration
can either generate new added value or bring
manufacturing costs down. Focusing on cutting costs
doesn’t make for good business, so we’re going to keep
pushing the added-value angle. Here, manufacturing

partners’ concerns center on whether new features arereally feasible in terms of performance and reliability.
The best way to put those concerns to rest is to install
the added-value component in an actual engine, run the
setup, and show the partners exactly how things went.
Technical demonstration results are huge differencemakers; if you can’t prove viability with hard, validdata, potential collaborators can get hesitant. The F7-10
engine to be installed at JAXA will be a big asset as a civilengine demonstration platform.
Nishizawa: You’re definitely right. We’ve known for along time about the difference between having and nothaving that kind of engine test bed. Why did the FJR710
evolve into the V2500? One of the biggest reasons wasthat we had Asuka, our own infrastructure, to do thedemonstrations on. If we were going to try to follow inthose footsteps, we needed an F7-10 engine test bed
that’d suit today’s technological levels.
— What kinds of outcomes has the aFJR project
had so far?
Nishizawa: I think it’s had two big effects. First of all, it’schanged the way JAXA tackles research and development.
We have usually based our operations around basic or
fundamental research, but the aFJR project embraces
a different approach. The end vision—making a jetengine, installing it, and flying the aircraft—is shaping
everything we’re doing. It’s a more applied style. Under
the aFJR framework, the demonstration data at theelement level is going to be an integral resource in thesubsequent, manufacturer-led phases.
The other thing we’ve seen come out of the aFJR
project is a new approach for projects to take. We’reworking with manufacturers and universities throughjoint-research arrangements. Whereas previous
collaborations have operated along the boundaries ofindividual research areas, with each project focusing
on one specific field, the aFJR project unites a variety offields together in the pursuit of a single goal: making aturbofan engine. JAXA hasn’t really done that type of
research and development before—and that makes it a
big step forward, I think.
Imanari: We joined the aFJR project because we wanted
to bolster our strengths in low-pressure systems. Being
part of the project has given us an amazing opportunity
to create an innovative model with such a diverse
makeup. We’re taking the technologies that the aFJR
team has created, the things we’ve developed with otherorganizations besides JAXA, and all the unique researchby different manufacturers and putting everything into
the F7-10 engine, validating the results, and making
proposals to Western engine manufacturers. It’s a reallydynamic process—and if it goes well, I think it’ll give
JAXA a blueprint for its next project. I hope JAXA keeps
the momentum going.

Lightweight, lowpressure turbine

High-efficiency, lightweight fan

Feature Story

Related Technology

Hollow CFRP fan blade andLightweight metal disk

Technologies of

the aFJR project
Creating lightweight, eﬃcient engines

Lightweight, sound-absorbing liner

The goal of the aFJR project is to develop technologies for a next-generation engine that has higher efficiency levels and weighs around 10% less than existing
engines. This section introduces four different technological endeavors of the aFJR project: high-efficiency, lightweight fan technology, lightweight disk
technology, lightweight, sound-absorbing liner technology, and lightweight, low-pressure turbine technology.

High-efficiency, lightweight fan technology
Making fans lighter through new
approaches to materials andStructures
Recent demands for more fuel-efficient turbofan
engines in various types of aircraft, including passenger
jets, have led manufacturers to pursue higher-bypassratio* 1 designs. Increasing the bypass ratio of anengine, however, generates larger volumes of air
intake—and thus leads to larger fan diameters. Whenfans get larger, engines get heavier; and when engines
get heavier, the airframes supporting the engines
follow suit, considering that they need the sufficientrigidity. As a result, the increase in overall weight canend up offsetting the improvements in fuel efficiency.

Tomo Takeda
Researcher
aFJR Project TeamTo create engines with high-bypass ratios and better
fuel-efficient performance, then, manufacturers needtechnologies for reducing engine weight.
“We’re trying to make engines lighter by replacing
metallic fan blade designs with carbon fiber reinforced
plastic (CFRP)-based designs,” says Tomo Takeda, wholeads the effort on lighter fan technologies at JAXA.
The project involves other goals, too: using a hollow
structure for the CFRP fan blade interiors, which makes
the engine lighter, and designing a structure capable ofwithstanding bird strikes and other forms of impact.
“For our impact simulations to estimate impactresistance performance, we started out by working
with several university partners to build complete
fan blade models,” Takeda explains. “We then used
computer technologies like JAXA’s supercomputers and
RIKEN’s ‘K’ supercomputer to do an enormous amountof calculations—more than we’ve ever done before.” Asthey conducted the many tests and calculations, JAXA
researchers drew on the results to modify the structureof the hollow portions of the fan blades and making
important advances toward a lightweight fan blade
design with good impact resistance.

Rethinking fan blade configurations
from an aerodynamic perspective
The aFJR project is about more than making fanslighter—improving overall aerodynamic efficiency
is another part of the initiative. With the “3D laminarflow blade design,” says Daisaku Masaki, who leads
the effort to enhance fan efficiency, “we’re working
to develop fan blades with better efficiency by
optimizing the configurations of fan blades from an
aerodynamic standpoint.” In concrete terms, theteam is working to improve aerodynamic efficiency
by creating a configuration that extends the laminarboundary layer on wider sections of the fan bladesurface. The air in a laminar boundary layer flows ina smooth, orderly fashion without turbulent eddy,
thereby reducing the resistance drag on the bladesurface and improving overall efficiency. While thetip of a fan blade also generates shock waves, higher
bypass ratios help neutralize that problem: A highbypass-ratio engine makes fan diameter larger, whichmakes optimum pressure rate ratio lower and reduces
the rotating speed of the fan, thereby weakening—oreven eliminating—the shockwaves coming from theblades and its loss. If the engine fan blade can keep tip
shockwaves under proper control through a 3D design,
the laminar boundary layers on the surfaces of the fan
blades last longer. JAXA is using the results of the Clean
Engine Project, which aimed to create a quiet, lowCO2-emission engine, to create a fan with world-class*1 The ratio of the amount of air bypassing (flowing outside) the core engine to the amountof air flowing into the core engine; a larger bypass stream leads to a higher bypass ratio.
11

Daisaku Masaki
Section Leader
aFJR Project Teamefficiency performance.

Establishing new technologies
through demonstrations in FY2017
The lightweight fan blade design is progressing. After
doing numerical simulations, the team built a halfscale hollow CFRP fan blade and conducted preliminary

tests on the prototype. The next step came in November
2016, when the team manufactured a full-scale hollow
CFRP fan blade and used it for preliminary tests toinvestigate impact resistance using a gelatin ballsimulating a bird strike. In addition to placing a strain
gauge on the fan blade and examining the readings,
the researchers also recorded instances of impact with ahigh-speed camera to observe the resulting changes. In
FY2017, JAXA is aiming to conduct final demonstration
tests on an improved hollow CFRP fan blade thatreflects the findings of the preliminary tests.
To evaluate the efficiency enhancements of its 3D
laminar flow fan blade designs, JAXA created a roughly
1/3 sub-scale model prototype in FY2016. The tests
involved installing an airflow-regulating device on theengine test cell and simulating the flow conditions withless turbulence at the intakes relative to what aircraft
experience during actual flight. Moving forward, JAXA
is planning to incorporate the results of its analyses into

a new sub-scale model and proceed with more testingin FY2017 to verify the technology developed under the
aFJR project.

technology and developing a design tool that
can accurately estimate the increases in fatigue
life resulting from shot peening. By applying theestimated increase in the fatigue life, based on the
results of both the shot peening simulation and theactual testing, to the design process, JAXA could findways of creating smaller, thinner fan disks while

maintaining the same fatigue life as conventional
disks.
The aFJR project team has been conducting its firstseries of fatigue tests on shot-peened sub-scale disks,simulating engine operation conditions with repeatedly
changing rotational speeds. In the planned second phaseof fatigue tests on sub-scale disks, the team is going to

A prototype of a hollow CFRP fan blade;the colors and lines are for observational
purposes.

Lightweight disk technology
The fan disk: An importantcomponent that works behind thescenesA fan disk must firmly support fan blades thatrotate at high speeds. Therefore, fan disks are “lifelimited parts,” which require replacement before
reaching the end of the defined fatigue life. The
larger the fan blade becomes, the larger the load thatthe fan disk must withstand grows. Herein lies thedemand for technologies to make fan disks lighterand tougher. To increase the fatigue life of fan disks,manufacturers often use “shot-peening” treatment—
a metal processing technique that involves impacting
metallic surfaces with small, hard balls of “shot” athigh velocities. By applying a compressive stress tothe surface of a metal, the shot-peening treatment
effectively delays the initiation and growth of cracks.
However, the increases in fatigue life that shotpeening treatment creates do not factor into thedesigns of fatigue life for conventional disks.
JAXA has been researching shot peening simulation

Shot-peening particles

Strain
Large

Small

A shot peening simulation (R) and analysis results (ex.) (L)12verify the accuracy of the fatigue life predictions of theshot peening simulations.

Fan disk

Lightweight, sound-absorbing liner technology
Resin: A lighter alternative toaluminum

JAXA’s advantages in evaluation
technology

The goal of JAXA's research on lightweight, soundabsorbing liners technology is to reduce the weight of theliner, which helps decrease engine noise, by making theliner with resin instead of metal (aluminum). According
to Tatsuya Ishii, “Resin is more than just a lightweight
alternative to aluminum; you can also cast resin into
single-piece configurations using molds—and thatmakes it a more cost-effective solution.”
A standard sound-absorbing liner panel consists ofa perforated surface sheet, a back sheet, and a hollow,
honeycomb-type structure between the two sheets.
When sound propagates through the small holes on thesurface-sheet side, it gradually decays as it passes throughthe sound-absorbing liner panel (the honeycomb-type
structure). Modifying the aperture ratio on the surface
sheet and the size of the honeycomb cells alters thefrequencies that the liner can absorb, thus making it
possible to specify target frequencies as needed.

JAXA is currently researching lightweight, soundabsorbing liners in a collaborative study with
manufacturers. For this research activity, JAXA is in chargeof a variety of evaluation tests on sound-absorbing liner
panels. The tests have two basic components: acoustic tests
and strength tests.
There are three stages of acoustic testing. The first stage
is “normal-incidence” sound-absorption testing, which
involves placing a small piece of a sound-absorbing liner on
one end of a duct, generating sound from the other end,
passing the sound through the duct, and determining how
well the liner absorbs the sound (the sound-absorptionrate) at a vertical (normal-incidence) angle. For the nextstage, researchers place a sound-absorbing panel in a flow
field, propagate sound through the field, and measure thecorresponding sound-absorption rate. In an actual aircraft
engine, the sound-absorbing liner is placed in a position
that comes into contact with airflow (on the nacelleinterior wall, for example); therefore, testing the liners
requires measurements of sound-absorption rates underboth static conditions (normal-incidence sound-absorption
testing) and grazing flow conditions. JAXA thus tests
liners using special a testing apparatus that places soundabsorbing panels inside a long duct with airflow running
through it. The last stage of the acoustic testing process is“fan rig testing,” which evaluates the acoustic performanceof a liner by placing a cylindrical sound-absorbing panels
in a test apparatus to simulate an actual fan setup. JAXA
uses a fan-testing apparatus from one of its joint-research

Researchers in front of the testing apparatus for evaluating the sound-absorption
rates of sound-absorbing liner panels in airflows

partners for the fan rig testing component—an important
step that helps identify practical issues to address, including
sound decay levels, frequency properties, airflow effects,
and structural integrity.
Strength testing verifies whether the resin soundabsorbing liner panel prototype is structurally strong enoughto function effectively under actual usage conditions.
Strength testing includes static load testing, which involves
slowly applying load to the component and evaluating
the component’s strength, and impact testing, which
confirms that damage resulting from impact (hail, etc.) on
the surface of the panel stays within an acceptable range.
For this portion of the research project, JAXA uses weightdrop testing—an approach that involves dropping weights
on the sound-absorbing liner panel to see if any breakage
occurs. The weights and drop distances that the researchers
use in their testing procedures are determined by the kinetic
energy of the impact.
Taking advantage of JAXA's
extensive range of evaluation
technologies, the researchteam continues to drive
progress in lightweight, soundabsorbing liner technologies.

Tatsuya Ishii
Function Manager
aFJR Project Team

Lightweight, low-pressure turbine technology
How ceramic components make seven stages. Each stage has a great number of rotor
turbines lighter
blades and stator vanes. Considering how many blades
A low-pressure turbine, which generates the power
necessary to rotate the fan rotor, generally has about

and vanes there are in a low-pressure turbine, reducing
the weight of the blades and vanes brings the overall

engine weight down considerably. Through the aFJR
project, JAXA is researching the possibilities of replacing
metallic low-pressure turbine blades and vanes withblades and vanes made of a Ceramic Matrix Composite

13

Takashi Yamane
Function Manager
aFJR Project Team

(CMC) in hopes of achieving the weight-reduction
targets: around 30% of the low-pressure turbine weightor 9% of the total engine weight.
“A CMC is a ceramic material, reinforced by ceramic
fibers, that has extremely low density and high heat
resistant characteristics,” Masahiro Hojo explains.
“Engine manufacturers abroad are already getting to
the point where they can equip engines with some CMC
components. It looks like CMCs are going to be playing
bigger and bigger roles in the future.” Nickel alloys are
currently used for low-pressure turbine material. If
CMCs were to replace nickel allows, they could cut theweight by a quarter to a third relative to the present
weight level—but CMCs come with their own share ofunique challenges.

Flutter and tangling design

According to Takashi Yamane, “We need to establish
technologies for flutter design and tangling design inorder to make CMC blades and vanes more reliable.”

Masahiro Hōjō
Associate Senior Researcher
aFJR Project Team

Flutter is a phenomenon that causes blades and vanes
to vibrate—the same type of thing that happens whenwind blows through the blinds on a window. Increasinglevels of flutter can cause damage, which means that
manufacturers aim for anti-flutter designs. Because
new materials like CMC have different characteristics,
it is necessary to identify and predict the flutter
margin accurately. In order to evaluate the accuracy of
prediction technology, it is also necessary to conduct
tests that cause a flutter. “We’ve developed some test
rigs for low pressure turbines and done some flutter
testing with aerodynamic vibrations,” says Jun’ichi
Kazawa, who is in charge of flutter research. In 2017,
JAXA is planning to conduct tests on actual-size models
and compare the results with CFD analyses.
“Tangling design” is a kind of structural design that
intentionally breaks low-pressure turbine rotor blades.
Jet engines require fail-safe designs in order to ensurethat no critical failures occur if the engine components
break. For instance, the low-pressure turbine disk—
sharing an axis with the fan—could lose resistanceand start rotating at extremely high speeds above
the designed rotating speed. The disk fragments fromthe breakage could penetrate through the engine
containment case and shoot out of the engine, exposing
the airframe to significant potential damage. Engine
manufacturers thus apply structural designs that caneliminate the torque power of the low-pressure turbine
in case of shaft breakage by intentionally breaking rotor
blades with stator vanes.
CMC rotor blades would need to conform to thetangling design methodology, as well. To date, thetangling design methods of breaking CMC rotor blades
at the root have emerged through a series of lowpressure turbine tangling simulations and preliminary
tests. The next step is to demonstrate the tangling
design methodology of breaking the high-speed
rotating CMC rotor blades through contact with stator
vanes using a spin tester.

Supporting Japanese industry
through CMC design technology

CMCs can increase the service temperature limit byroughly 100 to 200°C relative to metals. Although the
improvement of temperature-related performancelies outside the scope of the aFJR project, since low-

14

A low-pressure turbine
prototype for flutter testingpressure turbines do not currently require any cooling,
the extraordinary heat-resistant attributes of CMCs
could provide a significant benefit if future advances inengine performance lead to higher temperatures. JAXA is
currently studying the potential for utilizing CMCs in highpressure turbines, which operate at higher temperaturesand pressure levels than low-pressure turbines do.
CMCs continue to draw attention thanks to theirlightweight, heat-resistant properties. In addition topotentially revolutionizing engine turbine technologies,
CMCs could also find applications in gas turbine power
generation systems. Research projects along thoselines are already underway. There are two major CMC
material manufacturers—and both are Japanesecompanies, giving Japan a unique asset capable ofgiving the country an international competitive edge.
If the aFJR project succeeds in establishing CMC design
technologies, the results could both transform theaircraft industry and benefit Japanese manufacturingindustry as a whole.

Jun’ichi Kazawa
Associate Senior Researcher
aFJR Project Team

People"Navigating activities forthe certification of aviationequipment"
Takeshi Fujiwara
Associate Senior Researcher
Technology Demonstration Research Unit
Takeshi Fujiwara joined the National Aerospace Laboratory of Japan (NAL) in 1999
after obtaining a doctorate from the Department of Aeronautics and Astronautics at
the University of Tokyo’s School of Engineering. From 2007 to 2008, Fujiwara was avisiting scholar at Stanford University.
Fujiwara stands in front of the GPS experimentation dome* 1

Takeshi Fujiwara is an associate senior researcher who focuses mainly on developing air navigation systems. His current efforts also include
creating certification standards for developed avionics systems. In this story, he talks about what brought him to his current work at JAXA.
-Could you tell us a bit about your professional
background?
I’ve been interested in astronautics and robotics since
I was a little kid because I grew up with the popular TV
animation “Gundam,” where characters with robotic suits
transform into humanoid vehicles. I ended up followingthat passion all the way up to graduate school. As auniversity student, I learned about satellite dynamics
and interplanetary trajectories in the department ofaeronautics and astronautics, and my doctoral thesis wason satellite motion estimation. Ever since I joined JAXA
(which was then the NAL), I’ve been researching aircraft
navigation—technologies that help users understandthe aircraft position and motion.
Occasionally, I took part in various projects. For
instance, I was involved in the flight demonstration
project using a small supersonic experimental airplane
named NEXST-1*2. I was responsible for analyzing flightdata to help figure out how the experimental aircraft
flew. The experiments we did at the Woomera Test
Range in Australia left a lasting impression on me.
Another initiative I got involved in was the DREAMS
Project*3, which came up with technologies that we’re
now working to implement on a society-wide scale. Aspart of that effort hinges on formulating a system ofglobal rules, we’re currently proposing our ideas to theRadio Technical Commission for Aeronautics(RTCA), a
private, not-for-profit association in the United States.
I’m also assisting with airborne equipment certification
activities at the Next Generation Aeronautical Innovation
Hub Center, as well.
-What goes into airborne equipment certification?
All the equipment that makes up an aircraft needs toobtain certification from various authorities, including
the Japan Civil Aviation Bureau, the US Federal Aviation
Administration, and other aviation authorities. At
JAXA, we’re pushing to secure certification for a newly

developed inertial navigation system that combines
satellite navigation and inertial navigation technologies.
The new system actually operates on a softwarealgorithm that we originally developed for unmannedexperimental aircraft.
The interesting thing about the process, though, isthat there are no set standards for certifying this new
navigation system. Therefore, JAXA is making proposals
to the RTCA to help create the technical standards
ourselves for the system. That kind of approach, wherea product developer helps write the rules governing the
product, is actually fairly common abroad: Companies in
the US and Europe quite often use this approach for theirproducts. In that sense, Japan is gradually working its
way up to a position where it can make its voice heard in
rule-setting negotiations.
Size has a big impact on a company’s influence,
however. Considering that most Japanese equipment
manufacturers are much smaller than their foreigncounterparts are, it’s hard for them to hold much sway.
It’s JAXA’s job to create appropriate input to support
Japanese manufacturers, ensuring further benefits forJapan through being involved in the certification rulesetting process.
-Negotiation processes must be tough in manyways.
I think the toughest part will be software reliability
assurance operated under the US regulations. Oneof the problems is that the basic principles in theregulations sound abstract and vague to us, and there
aren’t any clear checklists or other resources that we
can use to check verification criteria or requirements.
US and European companies with long lists of successful
certifications often get through the process withease, but Japanese companies—which still lack thecredentials of their peers—often run into road blocks.
The new navigation system that we’re working on

is based on JAXA’s technology. Through developing
technical standards for the system, I believe we’ll be able
to take a step forward.
- What are the challenging and rewarding
aspects of your research on air navigation systems?
One thing about inertial navigation is that you canfigure out an aircraft’s position and motion using pieces
of indirect information, like acceleration and angularvelocity. I enjoy experimenting with those elements—
and the more you tweak a system, the more accurate theresults get. The challenges are worth it.
Today’s navigation systems have almost reached fullmaturity as standard flight technologies, which makes
it hard for new technologies to emerge. As GPS-based
satellite navigation has showed, however, compelling
new technologies have the potential to revolutionize theway the world works.
- What kinds of research do you want toaddress in the future?
I’d like to keep working on air navigation systems,
since I have plenty of ideas I want to try for improving
performance and usability. I’m also interested indeveloping a customized navigation system thatprovides optimal functionality and takes user needs andenvironments into accounts.
*1 The hemispherical dome is made out of a material that transmits
GPS signals, giving researchers an indoor environment where
they can conduct experiments without having to care about
weather conditions.
*2 An unmanned experimental airplane designed and built for
flight demonstrations of JAXA’s low-drag airframe designconcept; JAXA conducted experiments in 2002 and 2005 as partof its research on silent supersonic passenger transport.
*3 DREAMS (Distributed and Revolutionarily Efficient Air-traffic
Management system) is a project designed to develop the
key technologies for enabling next-generation air traffic
management systems; see FLIGHT PATH No. 7/8 for details.

15

People“To glean insight from simulation
results, you need to understandthe fundamentals of combustion
phenomena”
Yasuhiro Mizobuchi
Leader of the Combustion and Turbulence Section
Numerical Simulation Research Unit
After graduating from the Department of Aeronautics and Astronautics in the
Faculty of Engineering at the University of Tokyo in 1989, Mizobuchi went on to
obtain his master’s degree from the Department of Aeronautics and Astronautics
from the University of Tokyo’s Graduate School of Engineering in March 1992 and his
doctorate from the same department in March 1995. In April 1995, Mizobuchi joined
the National Aerospace Laboratory (NAL) of Japan’s Science and Technology Agency.

Mizobuchi poses with the automotive engine combustion simulation, which draws on aerospace technology-related input

In addition to fostering the younger generation as a section leader, Yasuhiro Mizobuchi constantly works to shed new light on how flames
behave, analyzing the various forms of combustion phenomena that occur in aircraft and rocket engines.
- Could you tell us a bit about your research,
past and present?
When I first joined the National Aerospace Laboratoryof Japan (now JAXA) about 20 years ago, most of mywork was on simulating gas combustion. The Laboratory
had a big computer capable of generating huge volumesof data, but I learned that technology alone isn’t enoughto produce insight: If you don’t have a solid grasp of thefundamentals at the root of a physical phenomenon,
you won’t be able to obtain new findings no matter how
many calculations you do. Whether or not you can glean
insight from a set of results depends on whether you
understand the basic physical principles and know theessentials of combustion phenomena. When you look at
something burning, you might just see a single flame—
but there are situations where the flame is actually a mixof different components with different properties. If you
analyze the structure of a jet lifted flame, for example,
you can see that the flame is a complex of three different
flame elements (see the Figure in the bottom-rightcorner). I actually made that discovery based on someadvice from one of my senior colleagues. The key tomaking new, eye-opening findings is having lots ofpeople look at the same thing from lots of angles. With
that diversity of perspectives, you get a better read on
the different sides of the phenomenon you’re studying.
These days, my research tends to focus on enhancing
simulation technologies for analyzing combustion
phenomena in aircraft engines and rocket engines.
I do detailed, large-scale numerical simulations
on supercomputers and, using that information
to understand the physical nature of combustion
phenomena, create models from the results.
Using the computational fluid dynamics (CFD)
technologies that we’ve cultivated in the aerospacesector, I’m also developing the core components ofsoftware that could eventually become a platform
for automotive engine combustion analysis inJapan. That project got its start when an automotive

16

engine researcher saw our analyses of rocket-engine
combustion and asked whether we’d be able to apply
our technology—which could produce analyses of thehigh-velocity combustion flows in rocket engines—
to automotive engines, too. The biggest difference
between the engines in cars and the engines in aircraftor rockets is that the automotive engine has moving
pistons and valves. JAXA happened to have a substantial
background in that area, having researched potential
methods for covering those types of engines. We then
got the opportunity to take part in the Innovative
Combustion Technology Project for the Cross-ministerial
Strategic Innovation Promotion Program (SIP)*1, whichbegan in 2014. The project unites multiple organizations,
including universities and automotive companies. JAXA’srole is to establish the basic framework for analyzing
automotive-type engines, and to integrate the individual
sub-models for the various operational processes inengines that other universities and organizations havebuilt. We call the software we are developing “HINOCA,”
naming it after a fire god in Japanese mythology.
-What do you find rewarding about your work?
Now, as a supervisor, the biggest reward for me
is seeing younger researchers in my organization dogood work. One of the most important parts of myjob is making sure the junior staff members have anenvironment where they can really thrive. It’s always
great to see those efforts pay off. HINOCA is anotherinitiative that I get a lot out of. All the simulation
software currently driving automotive development isforeign-made. Since the software suites are all black-box
systems, too, there’s no way to modify the code on theuser end. Even if you develop a good model, you can’t
install it right away. There’s a big need for Japanesemade software—and if we create a viable solution,
users are going to be able to cut down on the numbersof experiments they do, minimize test piece-production
costs, and change the automotive design process.

A software package with high-precision simulation
capabilities would not only aid in final product checks
but also enable CAE*2 and simulation technology-driven
design.
By constantly working to shed new light on how
flames behave, I think we’ll be able to push progressalong and move past the conventional simulationbased design process. We’ll eventually make it possible
to create designs that maximize the potential of
combustion fluids. With that ability, I’m confident
we’ll be able to make a difference in more than just theJapanese aircraft industry—the results could impact
the automotive industry and the rest of the industrial
community in Japan.

*1: Led by the government’s Council for Science, Technology andInnovation, the SIP is a national project that aims to lead science,technology, and innovation beyond the framework of government
ministries and traditional disciplines. For each of its research anddevelopment initiatives, the project selects a program director(PD) responsible for guiding the corresponding effort from basic
research to practical application and commercialization.
*2: CAE (Computer-Aided Engineering) facilitates preliminary
examinations for product design, manufacturing, and process
design by enabling pre-production computer simulations
and analyses that help streamline prototyping, reduce theexperimentation workload, and predict a wide variety of potential
problems.

Floating diffusion flame
islands
Rich turbulent premixed
flame
Leading-edge flame
A complex of three
flame elements
Diffusion flame
Lean premixed flame
Rich premixed flame
Schlieren visualization ofnumerically simulated jet
lifted flame

A flame Index-based flame structure analysis

The structure of a jet lifted flame

Sky Frontier
Hydrogen-utilization technologies play critical roles in limiting CO2 emissions.
JAXA’s ongoing efforts go beyond simply creating aircraft that conform to thecoming “hydrogen society”—they also involve research that makes hydrogenutilization more efficient. This article introduces a comprehensive outlook
of JAXA’s hydrogen-related work with Takayuki Kojima, Associate SeniorResearcher from the Next Generation Aeronautical Innovation Hub Center.

Hydrogen-utilization
technologies

The heat exchanger for the hypersonic pre-cooled turbo jet currently in development at JAXA features heattransfer tubes with a design that accounts for temperature difference-induced deformation.2

The need for CO2 reductions in theaviation field
To stop global warming, it is imperative to cut emissionsof CO2 and other greenhouse gases on a global scale. At the2015 United Nations Climate Change Conference (COP21),
representatives from around the world negotiated the “Paris
Agreement.”
The transportation field currently accounts for around
14% of the world’s total CO2 emissions, with the aviation
realm representing 11% of that ratio—just 1% or 2% of
the whole. While those transportation-related emissions
might now be just a small fraction of the total, efforts to cut
back on CO2 emissions are already in full swing in the nonaviation transportation arena as manufacturers continue todevelop hybrid vehicles, electric cars, and more. Considering
the environment-focused trends in other sectors, theaviation field will likely make up a larger proportion of all
CO 2 emissions in the near future. The International Civil
Aviation Organization(ICAO) has placed rigorous restrictions
on CO2 emissions, as well, making the need for research into
CO2-reducing technologies for the aviation field even morepressing.

Leveraging Japan’s strengths into viablehydrogen-utilization technologies
Fossil fuels like coal and oil are the major sources of CO2
emissions, and most of today’s aircraft use fossil fuels (jet fuel,etc.). Alternative fuels that emit less or no CO22 would makeit possible to bring CO2 emissions down across the board. One
such candidate is hydrogen. Availability and accessibility are
two of hydrogen’s biggest advantages: Producing hydrogen is

as simple as electrolyzing water, and the substance is a natural
byproduct of the industrial gas-refining process. According to
Kojima, hydrogen could also be an extremely cost-effective
solution. “Along with imports from other countries like
Australia, there are plans to use solar-power and wind-power
facilities in Japan to produce hydrogen,” he explains. “Thosekinds of efforts will definitely help make hydrogen more
affordable in the future.”
Hydrogen generates about three times as much heat asjet fuel per unit of weight, but that heat only amounts to
one-quarter of what jet fuel can produce per unit of volume.
While it does have extremely lightweight properties, in otherwords, hydrogen requires considerable amounts of storage
space. Making the most of hydrogen’s weight advantagemeans storing the substance in a light, compact, spaceminimizing fashion, which would require composite solutions
for lightweight storage tank capable of withstanding highpressure conditions.
JAXA can apply its wealth of expertise in developing
a viable hydrogen solution; JAXA has been researchingcomposite materials and structures to make lightweight yetstrong aircraft structures, and JAXA also has technologies for
producing and storing hydrogen for use in launch vehicles. In
addition, JAXA’s efforts now extend to integrating expertisewith non-aeronautics technologies, such as superconducting
motor technologies for maglev vehicles and fuel cell
technologies for automotive applications. Such efforts willdefinitely help bring Japan’s technological prowess together

Heat exchanger

Fuel cell

Propeller

Liquid hydrogen tank
H2O/air

H2O
Liquid hydrogen

Hydrogenq gas

PSuperconducting pump
Cryogenic liquid level gauge

Air
DC electricity

Battery
Void meters

Motor/inverter

The cryogenic void heater used to control
liquid hydrogen flow rates

into far-reaching, dynamic research.

JAXA’s efforts in developing hydrogenutilization technologies

Another example of JAXA’s research on hydrogen
application is on a hypersonic pre-cooled turbojet engine,which started in 2006. Designed for use in hypersonic aircraft
capable of flying at Mach-5 speeds, the engine burns hydrogenfor a dual purpose: generating propulsion and cooling (precooling) intake air.
JAXA is also at work on electric propulsion utilizing liquidhydrogen. The system uses a superconducting pump to supply
hydrogen from a liquid hydrogen tank to a fuel cell, whichthen generates electricity to rotate a fan and thereby produces
a propulsive force (see the Figure). To develop the systemfurther, researchers are currently looking into using the electric
propulsion-based aircraft from the Flight demonstrationof Electric Aircraft Technology for Harmonized Ecological
Revolution (FEATHER; see Flight Path No. 9/10 for details)
for experimentation purposes. Other ongoing initiatives
include research into a two-phase flow sensor (cryogenic void
meter), which would detect the flow rates of liquid hydrogentransported under cryogenic conditions. All of these projectfor hydrogen application technologies will help create asustainable and recycle-oriented society.

An overview of the liquid hydrogen-driven system for superconducting fuel-cell propulsion
The system uses a superconducting pump to supply hydrogen from a liquid hydrogen tank to a fuel cell,which then generates electricity to rotate a fan and thereby produces a propulsive force.
17

Basic and fundamental technology

FaSTAR-MoveAnalyzing the airflow aroundmoving/deforming objects
Researchers have routinely struggled to compute and analyze the complicated airflow
generated by the movement and/or deformation of airframe: airflow around thelanding gear, flaps, and other high-lift devices that are deployed and stored during
flight. This article summarizes an interview with Takashi Ishida, a researcher at the
Next Generation Aeronautical Innovation Hub Center, who explained JAXA’s ongoing
efforts to develop a CFD solver called FaSTAR-Move—an innovative solution toprovide high-speed computational analysis on the complicated airflow aroundmoving/deforming objects.
An example of an overset grid used by FaSTAR-Move for analysis■ Meeting airflow analysis needs
Modern aircraft developers rely heavily on computational fluid dynamics (CFD),
which simulates flight characteristics in a computer environment. JAXA has made CFD
an important part of its activities, developing HexaGrid—a tool for automaticallygenerating grids at world-class speeds—and a fast fluid analysis tool called FaSTAR(see Flight Path No. 7/8). Hoping to expand the reach of its offerings, JAXA has also
provided CFD solutions to numerous organizations, ranging from universities andother educational institutions to corporate development divisions. The solutions havenot been complete, however: FaSTAR does not offer the CFD resources that actual
aircraft developers need for analyzing the airflow around moving/deforming objects.
Although some commercial software suites overseas do offer that type of support, theytend to fall short of user needs due to high price tags, slow analysis speeds, and otherproblems.
FaSTAR-Move, which JAXA is developing as a FaSTAR extension, aims to provide
users with a fluid analysis tool that delivers accurate analysis results under moving/
deforming conditions at FaSTAR’s high speeds. “By utilizing FaSTAR-Move, users would
be able to conduct analyses on helicopters, tilt-rotor aircraft, tilt-wing aircraft, andairframes with moving/deforming parts like morphing wings,” Ishida says.

■ Analyzing the airflow around moving/deforming objects
via the overset grid method
CFD involves generating a computational grid by filling the target space withtetrahedral and hexahedral elements (cells) and then performing the corresponding
calculations. There are three types of computational grids: a Cartesian grid (where
the gridlines cross at right angles), a structured grid (which features a systematic cellarrangement), and an unstructured grid (where the cell arrangement is irregular).
Depending on the type and quality (fidelity, etc.) of the grid in use, the accuracy of
the resulting analysis varies. FaSTAR-Move employs the “overset” grid method, whichlayers together multiple Cartesian, structured, and unstructured grids. When a user
wants to analyze helicopter flight, for example, it can be difficult to simulate the flight
conditions with a single computational grid. FaSTAR-Move enables the user to createand superimpose separate grids for the rotating blade component and the stationary
fuselage, thereby making it easier to conduct the analysis. Given its flexibility, theoverset grid method thus offers a powerful solution for analyzing airflow aroundmoving/deforming objects. The versatility of the overset approach also pays off inanalyses of the vortices that form behind objects in motion—by layering a Cartesian
grid over areas where structured and unstructured grids get too rough, users canperform high-resolution analyses in a localized fashion (see the Figure below).
The overset grid method requires an exchange of information between the various

18

grid layers. For the FaSTAR-Move development team, that interconnectedness represents
the biggest technical obstacle—especially for exchanges with unstructured, irregulargrids, which make finding the proper overlap hard to do at high speeds.

■ Targeting a Ver. 1 release by the end of FY2017
FaSTAR-Move is a two-part system consisting of a moving/deforming object
analysis module, which handles the analysis of airflow around moving/deforming
objects, and an engine analysis module, which analyzes the cascades of engine fans,compressors, turbines, and other components. The moving/deforming object analysis
module is currently in advance development as the Ver. 1 piece, while the team isplanning to start work on the engine analysis module (Ver. 2) in FY2018. Having
commenced development in FY2015, Ver. 1 is scheduled for completion by the end of
FY2017. Although the software only supported single solid objects during its first year
in development, FY2016 has seen developers perform successful analyses of multiple
objects. Moving forward, the team is hoping to boost the software’s calculation speeds
and improve the user interface. JAXA is also at work on HexaGrid’s successor, called“BOXFUN,” which captures object configurations with greater fidelity and enables
large-scale grid generation of more than 100 million cells. Together, FaSTAR-Move and
BOXFUN will offer users a high-performance, user-friendly set of fluid analysis tools.
Flow direction

Structured grid
Flow direction

Overset grid

The image illustrates two analyses of a cylindrical form in a given airflow, with the
top portion using a structured grid and the bottom portion employing an overset
grid. The elements outside the immediate vicinity of the object (the locations in thedotted lines) are relatively indistinct in the structured grid but clearly visible at ahigh resolution in the overset grid, making the overset grid a clearer depiction of the
airflow (L: Computational grids; R: Mach-number distributions).

Basic and fundamental technology

Super-small
turbofan engine
technology
The NE2013 installed at an JAXA ATF; to monitor fan rotation, a clear-plastic part is applied to the front.

■ One of the world’s smallest turbo jet engines
One of the outcomes of the “Applied Research on Small Turbofan Engines” project,which began in FY2011, was the “NE2013” small turbofan engine. Built based on the
KJ66 turbo jet engine, a common system around the world, the NE2013 is enhancedwith JAXA’s unique expertise. In order to create a structure equivalent to those ofturbofan engines for passenger aircraft, JAXA applied a biaxial setup for the coreengine’s main shaft and reworked the compressor, bearings, and other components
accordingly. The NE2013 also features new designs for elements like the front fan andadds a low-pressure turbine to the system.
Boasting a maximum thrust of 176.4 N and a bypass ratio of 3, the engine delivers
an impressively compact structure with a fan diameter of 120 mm, length of 487 mm,
and weight of around 10 kg. The engine also runs on jet fuel or kerosene, ensuring
optimal usability.

■ The impetus driving JAXA’s R&D on super-small engines
By creating a super-small turbofan engine like the NE2013, JAXA is aiming tobolster its efforts in researching and developing aircraft jet engines. Recent advancesin computer performance have enabled developers to create models digitally, using
computational fluid dynamics (CFD) and other technologies, and simulate combustion,
as well. When it comes to building individual parts, however, researchers have to create
and test prototypes under actual operating conditions. Meeting that need is extremely
expensive: Tests on actual turbofan engines require individual parts, which often run
up considerable costs. Making a single fan blade, for example, can cost up to tens of
millions of yen. Given the cost-intensive nature of the process, there are limits on how
Fan rotation speed: 30,000 rpm
Fan pressure ratio: 1.2
Fan outer diameter: 120 mm

Compressor rotation speed: 126,000 rpm
Compressor pressure ratio: 2.7
Compressor outer diameter: 66 mm

Research on jet engines involves tackling numerous challenges, including thelimited availability of full-scale test facilities for actual engine and the huge costsof the tests themselves. This section profiles JAXA’s super-small turbofan engine,which gives researchers the kind of readily available, low-cost research device
that they need.

many prototype models a team can create.
The NE2013 is a scale model of an actual turbofan engine widely in use. Thanks tothe size of the model, researchers can create prototypes for R&D at minimal costs andconduct trial-and-error tests under limited budgets. Even 3D-printed parts can bemounted for testing. Currently, JAXA is carrying out a wide array of testing using theNE2013, from evaluations of turbine stator vanes with variable mechanisms to studies
of engine-control programs.

■ Capturing the potential of mass-produced super-small engines
To run the NE2013, JAXA uses its altitude test facility (ATF), where researchers cansimulate actual flight environments. Although the ATFs in Japan lack the capacity totest full-size engines, the facilities offer more than enough space for the small-scale
NE2013. In parallel to the ongoing testing at its ATF, JAXA is also looking into thepossibility of running the NE2013 in wind tunnels.
JAXA’s NE2013 boasts a high-TRL* for a research institution, and its technologies
are already in use in Niigata City’s “NIIGATA SKY PROJECT” for real engine development(see the column below). JAXA is hoping that initiatives like the NIIGATA SKY PROJECT
will help Japanese companies eventually transition the NE2013 into a viable, massproducible product. Mass-producing the NE2013—already much cheaper tomanufacture than the types of jet engines powering today’s aircraft—would bringthe market price down to several hundred thousand yen. Not only would that low-costaccessibility benefit Japanese research on aircraft engines, but it would also facilitate
installations on unmanned aircraft systems and give universities and other institutions
an affordable resource for educational applications.

NIIGATA SKY PROJECTThe NIIGATA SKY PROJECT, part of Niigata City’s efforts to energize the local
community, aims to support aircraft-related industries through industryacademic-government collaboration in the Niigata area. Drawing on local
companies’ expertise in mechanical metalworking techniques, the initiative is

NE2013 structure and specifications

High pressure turbine(outer diameter): 66 mm

Low-pressure turbine(outer diameter): 85 mmworking to develop a quiet, efficient, compact jet engine and an unmanned
aircraft system capable of transporting 100-kg cargo (cargo UAS).

* Technology Readiness Level, an index that represents a technology’s maturity on a scale of 1 to 9.

19

JAXA Aeronautics Symposium 2 0 1 6“Technological challenges andopen innovation”
The JAXA Aeronautical Technology Directorate organized a symposium in October 2016 in Tokyo
to introduce its challenges and vision toward future steps. Through keynote presentations andpanel discussions, the symposium introduced JAXA Aeronautics’s ongoing R&D efforts, with anemphasis on its open innovation policy that tries to incorporate diverse knowledge and insightsfrom universities, companies, and other players.
Opening remarks by Fumikazu Itoh, Director General of the JAXA Aeronautical Technology Directorate

Challenging high-level research that creates
added value, while encouraging timely
delivery of tangible outputs
On October 13, 2016, JAXA held “JAXA Aeronautics Symposium
2016: Technological challenges and open innovation” at Tokyo
Big Sight in Tokyo, Japan.
Emphasizing the synergy between technological prowess
and collaboration, this year’s symposium profiled JAXA’s efforts
to bolster society and industry by tackling ambitious technology
initiatives and quickly turning its research into real, practicalsolutions.
The opening remarks, titled “Looking ahead — visions andchallenges for JAXA Aeronautics,” were made by Fumikazu Itoh,Director General of the Aeronautical Technology Directorate.
In his remarks, Itoh addressed how JAXA Aeronautics takes
on technological challenges to better serve industry andsociety. Itoh’s remarks not only covered D-NET,*1 the D-SEND
Project, *2and other past achievements but also detailed
current research efforts like the FQUROH Project*3 and SafeAvio
Project. *4 Itoh also laid out the Aeronautical Technology
Directorate’s R&D management strategy : “promoting researchand development activities that benefits industry and society,”“multi-disciplinary and cross-sectoral collaboration for open
innovation,” and “incubating high-level research that creates
added value”.

Stimulating innovation in the aviation sector

The theme for the second part was “challenges for realizing
open innovation in aviation”. Three lecturers presented initiatives
centered around the WEATHER-Eye Consortium.*5

Airlines Co., Ltd. During his address, Kitada introduced issues on
special weather from an airline’s perspective, such as how wind
shear, volcanic eruptions, lightning, airframe icing, and similar
meteorological phenomena impact flight. Kitada voiced how
airline operators and users can benefit from the technologicalchallenges tackled by the WEATHER-Eye research initiatives,
such as better tools for detecting special weather conditions andsafeguarding against icing, which will lead to help increase air
safety and operational efficiency.
Shigeo Kimura, a professor in the Department of MechanicalEngineering at the Kanagawa Institute of Technology, introduced
the detailed mechanisms of how icing occurs, together withseveral research initiatives on anti-icing, de-icing, and icing
detection that the Kanagawa Institute of Technology has beencollaborating on with JAXA, manufacturers, universities, andEuropean research institutions.

How MRJ development and JAXA can shape
the future of the aviation industry

The third part of the symposium was a panel session
featuring Kiyoshi Sakura, Deputy Head of the Engineering
Division at Mitsubishi Aircraft Corporation, and Takeshi Ohnuki,
Program Director of Aeronautical Technology at JAXA. They
spoke about the MRJ project and JAXA’s role for the future of theJapanese aviation industry.
After covering the current status of the MRJ development
effort, Sakura introduced research collaborations with JAXA todevelop and test technologies from the basic design phase. He

also expressed his expectations for JAXA’s ongoing R&D efforts
in innovative technologies while also voicing his hopes forcontinuing collaborative research with JAXA. Ohnuki (from JAXA)
summarized the panel session by underlining the importanceof making collaborative research and development efforts withindustry while ensuring the benefits that these collaborations
can have for the Japanese aviation industry.
In the ensuing question-and-answer session, the presentersexchanged their views on ideas and issues raised by theaudience. Themes included more demands for aircraft component
research, the need for human-resource development, and more.
Sakura added his comments on JAXA’s role, saying that it would
best help companies if JAXA continued pursuing its research on
both short-term and long-term themes that companies lack
the resources to tackle. Through a series of presentations anddiscussions at the symposium, it had become even clearer as
to how JAXA and companies could best share their roles andresponsibilities.
*1 Disaster-Relief Aircraft Management System Network; see FLIGHT
PATH No. 7/8 for details.
*2 Drop test for Simplified Evaluation of Non-symmetricallyDistributed sonic boom; see FFLIGHT PATH No. 11/12 for details.
*3 Flight Demonstration of QUiet Technology to Reduce nOise from
High-lift Configurations project; see FLIGHT PATH No. 13/14 fordetails.
*4 R&D of onboard safety avionics technology to prevent turbulenceinduced aircraft accidents project; see FLIGHT PATH No. 13/14 fordetails.
*5 See page 6.

The first lecturer was Shigeya Watanabe, Director of the JAXA
Next Generation Aeronautical Innovation Hub Center. Watanabe
began with an introduction of the Center’s three policies:
pursuing initiatives that can benefit industry and society,driving open innovation, and delivering high-impact results. In
addition to providing an overview of each ongoing initiative,
including those related to WEATHER-Eye, he also touched on
JAXA’s new research on component certification technologies—
an emerging area where the social needs are pressing and thepotential impact is enormous.
The next presenter was Yuichi Kitada, Deputy General
Manager of the Engineering & Maintenance Division at Japan
The panel session included discussions of the MRJ development project20