In the world of new small airliners where extended development programs have become the norm, the Embraer E190-E2 flight-test effort stands out from the crowd for not only sticking to schedule but also proving design maturity early in the program.
The progress belies the fact the airliner is not merely a reengined version of the first-generation E190 but is composed of 75% new parts. These include a redesigned wing, smaller empennage, different landing gear and improved systems. Yet despite the scale of the changes, as if to underline its confidence in the aircraft’s maturity and the test effort in general, Embraer surprised many by flying the E190-E2 prototype across the Atlantic to appear at the Farnborough International Airshow in July, just 45 days after making its maiden flight.
“We have more than 160 flight hours so far out of a planned 2,000-flight-hour test schedule,” says Rodrigo Silva e Souza, marketing vice president of Embraer Commercial Aviation. “It is going really well, because in just over three months of flight testing we are doing much better than our direct competitors did, or are doing, at this point. It took the [Bombardier] C Series seven months to get to this point and the Mitsubishi MRJ has yet to get there.”
The company also knows that by good planning or fortune, perhaps both, the timing of the E-2 enabled it to take advantage of improvements made latterly by Pratt & Whitney to its PW1000G geared turbofan, which forms the core of the new airliner plan. Announced at the 2013 Paris Air Show, Embraer’s decision to inject new life into the E-Jet hinged on leveraging enhancements to the C Series PW1500G, which is modified into the PW1900G for the E-190/195-E2, and the MRJ’s PW1200G, which will be developed into the PW1700G for the E175-E2.
By late August, aircraft 001 had amassed about 85 hr. on 33 flights while 002, the second test aircraft, which joined the program on July 8, had flown almost 77 hr. over 22 sorties. The third test aircraft is expected to make its first flight by the end of August, while the fourth, and final member, of the test fleet is due to join the program around the end of the year.
Embraer credits two key elements for the E2’s steady progress: experience based on the development and service life of the original E-Jet family, and lessons learned during the testing of seven new aircraft types, ranging from business jets to the KC-390 tanker/transport, over the past 12 years. “Nobody has done that in the industry, and we have been disciplined enough to learn from each one of them,” says Souza, who adds that the E2 has also directly benefited from experienced personnel who have been involved in technology development across numerous programs. “The technical leader for the fly-by-wire (FBW) system worked on the first-generation E-Jet, the Legacy and Phenom [business jets]. How many companies have the benefit of leaders like that?” he boasts.
One of the biggest lessons Embraer took to the bank with the E2 was the company’s close focus on ground testing and the extensive use of multiple rigs and “iron birds” at its Eugenio de Melo facility in Brazil.
“To make sure we were correctly designing the aircraft and its systems, we performed extensive tests on different components, including highly accelerated lifetime tests, until they really broke,” says Souza. “Simultaneously, we conducted integrated tests as well as individual system tests. We then integrated all the different test benches [and] were able to evaluate the hydraulics, electrics, landing gear, flight control surfaces and FBW systems together as one iron bird. The plan is to accumulate 40,000 test hours, and right now we have achieved over 20,000, so we are more than 50% of the way through our ground test target,” he adds. In addition to the iron bird, the E2 program continues to ground test discrete elements of the aircraft using nearly 20 different rigs.
In flight tests the E2 is “doing as expected,” says Souza. “Some data are preliminary and we still have to do the main handling qualities testing. However, since the first flight, feedback from the pilots has been very good. They feel they are flying in the first-generation E-Jets, which is what we wanted to achieve.” This became quickly apparent following the first flight of 001 on May 23 from the company’s facilities in Sao Jose dos Campos, Brazil, before testing moved to Embraer’s flight facility at Gaviao Peixoto. Company test pilot Mozart Louzada commented that “control harmony in rolls, pitch and using the rudder was all very good and, most important, very like the current E-Jets. So we were able to verify that they fly about the same. As an E-Jet pilot I certainly felt at home in the E2, despite the differences in the flight deck displays and the changes in technology and equipment.”
Louzada also remarked on the performance of the aircraft’s PW1900G engine, which, like the higher-bypass-ratio PW1100G on the Airbus A320neo, appears to offer a marked improvement in second-stage climb with faster acceleration and responsiveness over current engines. “We have a Legacy 500 chase plane and we were climbing faster than they were. I had to throttle back to let them catch up. It took us less than 18 min. to climb from 20,000 ft. to 41,000 ft., and that was without using maximum available thrust,” he says.
Souza notes, however, that “for the E2 the main focus was not to improve performance and capability. Because of feedback from operators, all our focus was on reducing operating cost and fuel burn.” The E190-E2 is designed to have 16% better fuel burn than the current series, 11% of which will be from the PW1900G, 3.5% from the improved aerodynamics of an all-new high-aspect-ratio wing and 1.5% from the use of a fourth-generation EBW. This principally enables the empennage to be 20% smaller than that of the C Series, says Souza. The horizontal stabilizers are 250 ft.² in area versus 280 ft.² on the E190/195.
“As far as engine performance, we are still collecting data. We just do not have the critical mass of data to know exactly yet, but so far there are no surprises,” says Souza. However, after the 12-hr., 40-min. flight to Farnborough from Sao Jose dos Campos, with technical stops in Recife, Brazil, and Cape Verde, off the coast of Africa, for refueling, the flight crew “actually reported [fuel burn] below what they expected,” he adds. Actual in-flight cruise performance will be measured officially during upcoming in-flight-thrust-determination (IFTD) tests, the Embraer equivalent of nautical air mile survey (NAMS) tests conducted by Boeing. These are due to be performed on aircraft 002. “We are all waiting for the results of that test campaign, which should be later this year or early in 2017,” says Souza. In addition to performance work, 002 will be focused on systems tests. Aircraft 001 is also allocated to systems test work as well as loads and aero-elasticity testing. It will also be used for external noise and crosswind trials.
The third aircraft will become the main flying-qualities test platform, focused on aerodynamics and performance of the new wing, with icing tests set to take place somewhere in North America in early 2017. The fourth aircraft, which will be fully engaged in the test effort by early 2017, will be configured with a production standard interior for cabin testing. These will include cabin evacuation, interior noise and environmental control.
As for the PW1900G engine, Embraer Commercial Chief Operating Officer Luis Carlos Affonso has acknowledged that the company faces “some” of the rotor bow-related startup issues that Airbus encountered with the larger PW1100G on the A320neo. However, Souza says, the impact is minimized for Embraer. He attributes this partly to the smaller size of the E2 engine, and notes that it is fan-mounted, unlike the A320neo, which is core mounted. “We do need some time for the engine’s motor to start (an action that helps improve thermal equilibrium inside the core, counteracting any residual rotor bow in the low-pressure shaft), but it is a much shorter time. It takes 15-30 sec. for the engine to motor, which we don’t see as an impact,” says Souza.
Later in 2017, the year before the E190-E2 is scheduled to enter service, the four E2 test aircraft will be joined by the first of the next family member, the E195-E2. Two aircraft will be assigned for the E195-E2 certification program targeted at entry into service in 2019. Three test aircraft will be used to certify the E175-E2, which is scheduled to enter service in 2020. The E190-E2 seats up to 106 in a single class, or the same as the current-generation E190, but it has 2,800-nm range or 400 nm. more than today’s production version.
Embraer now has 670 commitments—including 272 firm orders and 383 options and purchase rights—for the E-2 family from airlines and leasing companies.
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