In late 2012, 's EcoDemonstrator undertook a secretive test effort to prove out the natural laminar-flow capability of a near-production representative advanced winglet design.
The results confirmed that Boeing could make a winglet with design tolerances sufficient for laminar flow at production-rate levels, clearing the way for the key drag-reducing design to be featured on the forthcoming 737 MAX. Just as important to Boeing, the tests came in the nick of time for the final design freeze of the MAX and proved the value of the EcoDemonstrator concept—a program to fast-track the testing, refinement and completion of new technologies that improve efficiency, sustainability and environmental performance.
Now, with the first EcoDemonstrator refurbished and in regular service with, Boeing is preparing for two successive follow-on test efforts that are more ambitious in terms of both scale and breadth of technologies. The two programs—a modified 787 that will fly this summer and a radically reconfigured 757 scheduled to be tested in 2015—will evaluate a raft of new airframe, systems, propulsion and flight-deck technologies that could be introduced into the production line within this decade or a few years beyond.
Testing of the advanced winglet “is a good example of some of the benefits of having a regular demonstrator available,” says Boeing program manager David Akiyama. “When the MAX program came out with a production technical challenge, we had a vehicle ready to test it. If we [had] not, we would not have had the time to prove it, and we would have had to introduce the technology in a later generation. We had a build concept we could produce at rate, and flying a near-production representative flight-test article was key.”
Boeing is also banking heavily that the experiences gained on the 737-based EcoDemonstrator will increase the number of technologies to be tested on both the 787 and 757 programs. “We learned a lot of lessons on how to pack things in,” says Akiyama. Compared to the 737, which ended up being used to evaluate roughly 15 discrete technologies, “we are looking at between 30 and 35 technologies on the 787,” he adds. The 737 experience also helped Boeing determine a more realistic schedule for the EcoDemonstrators—the second of which was originally expected in 2013. “We planned for a constant cadence of EcoDemonstrators and we are still figuring out what the natural rhythm should be. It looks like an 18-to-24-month cycle gives researchers time to research and learn lessons from previous demonstrators,” he says.
Boeing will begin conversion of its early development, ZA004, into the second EcoDemonstrator in early May following completion of engine certification duties for the -powered 787-9. “We will probably start flying around the June time frame and fly through July,” estimates Akiyama. Flight tests will mostly be based within the Seattle area with visits likely to Moses Lake in Eastern Washington and possibly to Victorville, Calif.
The 787 will be used to flight-test technologies in six key areas that cover propulsion, connectivity, materials, flight deck, flight sciences and flight-test efficiency. One of the aircraft's Trent 1000 engines will be fitted with a nozzle, plug and sleeve fabricated from ceramic matrix composites (CMC). Developed under a joint effort between Boeing, ATK affiliate COI Ceramics and Albany Engineered Composites, the CMC nozzle has been undergoing noise, structural and endurance ground tests on an engine at's Stennis facility. “It is a new-generation material and it promises to help us with propulsion because CMCs are lighter and can sustain higher temperatures. That will help us drive engine temperatures up and yet still be more reliable, so the engine will stay on-wing longer. We think it will be 20 percent lighter with a proprietary nose treatment on it,” says Akiyama. “When you design the whole engine with this material and with this higher-temperature capability, and it takes less weight and drag, you enter a virtuous cycle,” he adds.
The focus on flight-test efficiency is “a new area. There is a large cost and cycle time involved in doing a lot of flight-test instrumentation, so we are seeing if we can reduce cost and improve the efficiency of flight test,” says Akiyama. Technologies to be tested include micro-electro-mechanical systems (widely known as MEMS) transducers and wireless connections that could potentially reduce the volume of dedicated test wiring.
While the 787 is perhaps one of the most thoroughly understood aircraft Boeing has yet developed from an aerodynamic perspective, ZA004 also will play a role in advancing this area of flight science. “We will be doing some basic research. The aerodynamicists want to instrument the wing because, although we know how it performs in service, they want to take it to the next step to correlate computational-fluid-dynamics predictions with real data,” he says. The work also will look at ways to get laminar flow over more of the nacelles than is already achieved. “Maybe we could do something better for manufacturing from the technology we will be testing.”
Flight tests will also include “innovative technologies to build things quicker and lighter,” says Akiyama. Part of the focus will be on better management of heat in the engine nacelle and pylons where currently there is concentrated use of expensive alloys and metals such as Inconel and titanium. “So we are looking at areas where we can use more composites,” he adds.
Inside the cabin and flight deck the tests will focus on technology to improve situational awareness, “decision support” and health management. The work will build on the configuration that was tried out on the 737, which included a SwiftBroadband intermediate-gain antenna from CMC, asatcom data unit and a Boeing-built Onboard Network System, which is a network file server that connects via a wireless network to other aircraft systems. “We used SwiftBroadband on the 737 but would like to use a Ku-band satellite system on the 787. So we are working with suppliers to hook up the aircraft with a broadband pipe. We like to think the 737 was the first step toward more data-intensive airplane health-monitoring and management as well as [improved] weather sensors and the networking of that data.”
Flight-deck technologies under test will include touchscreens and experimental displays of information on the heads-up display for better situational awareness. This will include new synthetic-vision concepts. “It is all the things we envision in the next generation. The 787 is perfect for this because it is a blank canvas and has all the software,” Akiyama says.
In conjunction with display work, the 787 also will be configured with experimental flight-control-law software to pave the way for the next generation of aircraft, “as well as to improve the current generation,” he says. “There will be changes to the 787 for improved tail protection and changes to the high-lift system [leading and trailing edges] to reduce noise and enhance handling.”
Plans for the follow-on 757 EcoDemonstrator are well advanced, too. The aircraft, leased from U.K.-based partner airline TUI, is stored at Boeing Field in Seattle where it will soon be radically altered to install a new active flow control (AFC), vertical tail and numerous other changes. Flight tests will be broken into three major phases and conducted throughout 2015.
Modifications to the tail will be based on results from evaluations of a full-scale 757 tail, equipped with AFC, which demonstrated increased rudder effectiveness in wind-tunnel tests run late last year by Boeing and. The tests used AFC to increase rudder sideforce on demand by delaying airflow separation over the deflected control surface. Using data from the tests, Boeing will position airflow actuators and instrumentation at specific points upstream of the rudder hinge. The ultimate goal is to reduce tail size and therefore drag.
“We will also do some wing changes,” says Akiyama. Various advanced-wing concepts ranging from morphing to laminar flow are being considered. “It is all on the table. We like to think of the 757 as a tool kit,” he adds. The morphing wing work builds on adaptive trailing edge technology tested on the 737 in partnership with the's Continuous Lower Emissions, Energy and Noise (Cleen) program. Tests of the CMC nozzle on the 787 are also part of Cleen.
Other technologies lined up for testing on the 757 include new cabin sidewall panel materials, a yet-to-be-selected advanced auxiliary power unit concept and new flight-deck displays for assisting crews in better managing speed in congested terminal areas for improved spacing. Ground collision avoidance systems for safer surface operations also will be tested. “We are looking at better situational awareness, as this will be really important for big aircraft like,” Akiyama adds.