Experimental Aircraft Testing Many Honda Innovations

By Ann Correspondent Christopher Armstrong

Honda Motor Co. Ltd. unraveled the shroud of secrecy surrounding its experimental jet at Airventure 2005 in Oshkosh, WI, flying the Hondajet in from its home base at Piedmont Triad Airport in Greensboro, NC.

"This public world debut of the HondaJet represents the continued advancement of Honda's long-standing dream of aviation," said Michimasa Fujino, HondaJet project leader and vice president of Honda R&D Americas, Inc. "We are pleased and excited to be able to share this dream and our technology with the aviation community."

First flown in 2003, the Hondajet made its world debut at Oshkosh, taking a short break during its planed 200 hour flight test program.  The 6 seat Hondajet is powered by two HF118 engines developed by Honda.  These very fuel efficient high-bypass turbo fans produce 757 pounds of thrust each and are mounted on a strut projecting up from the wing. 

This design increases Cabin volume by eliminating the need for engine mounting structure in the aft fuselage, and increases the drag divergence Mach number which reduces drag at high speed.  With a 420 knot maximum speed the Hondajet is designed to be faster and more 40% more fuel efficient and 30% more spacious than current light jets.

This over-the-wing engine-mount design is one of several innovations in the Hondajet that has been computer optimized to increase the aircrafts performance.  Honda R&D Americas project leader Michimasa Fujino presented a forum in the Honda Motorcycles Pavilion Thursday after the aircraft arrived.

The aircraft utilizes a custom natural laminar flow airfoil for its wing. Honda's proprietary SMH-1 wing section achieves low drag and excellent performance at high speeds despite its relatively high 15% chord thickness.  Typical business jet airfoils are 9 to 12% thick. The SMH-1 achieves laminar flow over the forward 42 percent of its upper surface and 63 percent of the lower surface.

Honda developed the airfoil using CFD methods, wind tunnel tested it and then test flew it on a T-33 by using a glove over the wing. In order to realize the benefits of the laminar flow section the wing must be manufactured with an extremely accurate and smooth surface.  Honda used an integrally stiffened one piece skin in the all aluminum wing.

The fuselage nose has also been designed to maintain laminar flow, which is a more difficult problem due to the 3 dimensional shape of the flow. To achieve laminar three dimensional flows, not only must the adverse pressure gradient need to be minimized but the design must maintain straight streamlines to eliminate cross flow.  The fuselage nose and tail use honeycomb cores while the constant section element is a co-cured panel with stiffening ribs and stringers.  This combination of structural methods reduced weight and increased interior space.

For a research aircraft the Hondajet has an extremely well equipped instrument panel. A Garmin G1000 glass cockpit system is used to present information on flat-panel flight displays. The Hondajet was displayed briefly at the center of Aeroshell Square and then moved to a hanger to prepare it for return to North Carolina.

FMI: http://world.honda.com/