Exit: Honda Aircraft's wing thing

The company has decided to make the most of its new airplane’s unusual design.

Rather than downplay the HondaJet’s unconventional look, with its over-the-wing engine mount (OTWEM), the manufacturer has chosen to embrace it. The new ad campaign features a series of clever images that suggest the frontal shape of the developmental jet, with appropriately positive connotations. Knowing the history of the HondaJet’s development, I love it.

I wrote about the program in the September 2003 issue of BJT’s sister publication, Aviation International News. When we first caught wind of the project in Greensboro, North Carolina, I thought it was just the continuation of Honda’s aeronautical research, which dated back to at least 1993. That’s when Honda began working with the University of Mississippi on a composite light jet prototype that never got beyond the test-flight stage.

In 2000, Honda teamed with FBO Atlantic Aero in Greensboro to develop a 24,000-square-foot research center—ostensibly a skunkworks project—that didn’t raise many eyebrows at the time. There were no press releases, so who knew? Maybe everyone thought Honda would continue to dabble in aviation, but not seriously. Toyota had just tantalized the general-aviation press with development of a piston aircraft engine based on its Lexus powerplant. But after a successful first flight, that automaker shelved its project.

The first official information to come out of the Honda facility concerned the 700-pound-thrust engine it was developing. On June 10, 2002, the company announced that the small turbofan—which would ultimately become the GE Honda HF 120—flew for the first time, taking the place of one of the Williams engines on a Cessna CitationJet test bed airplane. There was an offhand mention in the press material of a CJ-size airframe in the works that would be lighter and have a larger cabin, but not much else.

When the first image of that airframe appeared, it left a lot of experts perplexed. Why were the engines mounted on pylons above the wings, rather than on the tail? Mounting engines on wings is as old as jet airplanes, but the conventional wisdom is that it’s best to carry them under the wings. If the wings were slung too low to have enough ground clearance, then fuselage-mounted engines back by the tail were the logical next choice.

Trying to find out more, I contacted Honda’s public relations department. While communications director Jeffrey Smith acknowledged (barely) that the airplane existed, he insisted there was no business plan, no more technical information available and no timetable for anything more to be released. But at the end of the conversation, he cryptically asked whether I’d read the “engineering papers.” Engineering papers?

Honda’s chief designer Michimasa Fujino, who became the founding president and CEO of Honda Aircraft Company, had written some scholarly white papers for an engineering society, and Smith told me where I could get them. From those papers, I learned all about Fujino-san’s research on advanced laminar-flow principles and about the prospects for “OTWEM,” which is now embraced as the signature style of the HondaJet. The technical benefits include increased cabin space (since the support structure for the engine mounts doesn’t intrude on the rear cabin area) and simplified fuel, hydraulic and other systems. But back then, over-the-wing engine mounts were considered simply strange, and the business aviation marketplace has a history of brutal treatment for what are labeled “FLAs”—Funny-looking Airplanes.

Further research revealed that Fujino had used wind tunnels and computer programs to conquer all the aerodynamic hurdles involving OTWEM. Testing showed that the engines’ air inlets could be angled to receive sufficient airflow in all flight regimes. And remarkably, the engine pylons could be configured in such a way that their drag was the equivalent of a “clean” wing. It’s as if the engines are hanging in free space.

It has taken a while for the HondaJet to come to market, and it’s the combination of price, operating cost, performance, cabin comfort and perhaps timing that mark the success or failure of a new business jet. Whether this airplane flies or flops, I find Honda’s strategy of whimsically using the OTWEM shape as a marketing tool to be refreshing, particularly in an industry not usually known for its sense of humor.

Mark Phelps is a managing editor of BJT sister publication Aviation International New​s.