Honda Motor is starting to reveal more details of its confidential HondaJet business jet flight test programme amid mounting rumours the Japanese company is preparing to buy an existing US-based aircraft maker to initiate full production.

Honda, which also revealed the first significant details about the aircraft's indigenously developed HF118 turbofan engines, now admits the aircraft "successfully completed initial flight tests this month at Piedmont Triad Airport in North Carolina".

The company also claims that advanced design features of the HondaJet and its HF118 combine to "achieve fuel efficiency over 40% higher than conventional aircraft." Outline details of the composite fuselage, overwing mounted engine configuration business jet were first revealed in Flight International earlier this year, and news of flight tests emerged only last week (Flight International, 16-22 December).

The bulk of the improvement is believed to come from the engine, which has been revealed as a two-spool turbofan with a single fan stage, a two-stage compressor and two-stage turbine.

Honda says it has "created the first ultra-compact full authority digital electronic control system for this class of engine" and adds that 110h of flight tests (most of which have been accumulated on a Cessna Citation testbed) have been amassed since development began in 1999.

With a take-off thrust of 1,670lb (7.4kN), the 2.9 bypass ratio engine has a fan diameter of 0.44m (1.5ft), a length of 1.38m and a dry weight of 178kg (392lb).

Honda, which started research into "compact" business jets in 1986, says the HondaJet is scheduled to undergo around 200h of flight tests "to demonstrate and verify the operability and performance characteristics of its various systems".

In particular it plans to evaluate the potential low drag characteristics of "Honda's proprietary turbulence-reducing laminar aerofoil," as well as the natural laminar flow nose section.

One of the potential buy-outtargets for Honda is believed to be Bombardier's Learjet operation in Wichita, Kansas, which is reportedly for sale. Honda was unavailable for comment, while Bombardier says that "there is no truth to the rumour that we are selling Learjet".

Source: Flight International