lørdag 21. mars 2015

HondaJet - Snart sertifisert i USA

Carmaker shatters tech taboos to give dream wings

CHIKARA NAKAYAMA, Nikkei Monozukuri deputy editor
The first mass-produced HondaJet
TOKYO -- After decades of painstaking preparation on the ground, the HondaJet is finally poised for commercial takeoff, with the first plane slated to be delivered this year.
     The project has drawn considerable attention, as it marks Honda Motor's first foray into the aircraft business. The small business jet is also symbolic of the recent trend of innovation among Japanese manufacturers.

Change is in the air
The HondaJet boasts an array of new technologies that the automaker developed by breaking taboos in the aircraft industry.
     In September last year, potential customers were given a chance to take the HondaJet for a test spin. Many of the people eyeing the jet are pilots themselves, and Honda is confident they will appreciate the differences between its plane and conventional business jets.
     Michimasa Fujino, president and CEO of Honda Aircraft, the U.S. subsidiary in charge of developing and manufacturing the aircraft, has likened the jet to a luxury sports car. Features that set the plane apart, Fujino said, are its spacious cabin, responsiveness, and excellent acceleration and climbing ability thanks to a lightweight body and powerful engines.
     Also imparting a sense of luxury, he said, are its minimal vibration and noise during start-up.
     Of the various original features incorporated into the jet, perhaps the one that stands out most is the engine placement.
     While most business jets have engines on the rear part of the fuselage, the two engines used for the HondaJet are mounted on the main wing. The company says the proprietary design not only results in a much more spacious cabin, it also enables a higher maximum speed and better fuel efficiency.
     Mounting an engine on the main wing was long considered a big no-no for business jets. The argument was it would create too much aerodynamic drag between the nacelle, which covers the engine, and the main wing.
     Honda began questioning that view, asking itself if perhaps such a design was not only possible but superior. That spark of curiosity essentially marked the start of the HondaJet development project.
     Mounting an engine on the main wing was not easy. The company needed to identify an appropriate position for the engine while taking into account steering stability, vibration characteristics and drag. After tinkering with a huge number of variables, Honda discovered the engine's sweet spot, the place where aerodynamic drag was held to a minimum.

Uncharted territory
Other original features of the HondaJet are drag-reduction designs for the main wing and fuselage, and the use of carbon fiber-reinforced plastic to reduce weight.
     For the main wing, the jet uses what is called a natural laminar flow wing. This type of wing is characterized by a high lift coefficient, excellent stall characteristics, low drag while gaining altitude or cruising, and minimal pitching at high speeds.
     But this type of wing has its drawbacks and was long seen as unsuitable for business jets due to their high speeds. Here again, however, Honda challenged the status quo.
     In designing the shape of the wing, Honda entered uncharted territory. And this pioneering approach was also evident in the company's experiments to test the HondaJet's performance. To make the aircraft lighter and boost its performance, Honda used two types of carbon fiber composite materials for the fuselage.
     In addition to adopting original technologies for the aircraft structure, Honda is also using unique production processes. This includes how the plane is painted.
     Honda places extra importance on the painting process because "improving the quality of the painting directly leads to an improvement in the salability (of the aircraft)," said Honda Aircraft's Fujino.
     The HondaJet's production plant is in Greensboro, North Carolina. It has two painting booths, with the air flowing in a different direction in each.
     In the "crossdraft" booth, air for ventilation flows horizontally, from the front to the rear of the aircraft. In the "downdraft" booth, air flows vertically, from the top to the bottom of the aircraft. The crossdraft booth is for the primer coat and the downdraft booth is for the top coat. The setup is aimed at achieving maximum quality and efficiency.
     The HondaJet is now undergoing final checks by the U.S. Federal Aviation Administration before its delivery to customers later this year. FAA pilots are conducting final test flights using four test planes.
     Bringing the jet from concept to reality has been a long, three-decade journey for Honda. The Greensboro plant has already begun assembly work, operating at a pace of 80 units per year. Finally, Honda's dream is about to take flight.

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