Honeywell is deep into the design of a novel weight-cutting, fuel-saving, vibration damping engine mounting technology to be used for the first time on Embraer's Legacy 450 super-light and Legacy 500 midsize business aircraft.

Set for entry into service in 2013 and 2012, respectively, the 450 and 500 feature fly-by-wire flight controls accessed through a pilot side-stick controller, the first application of a side-stick by Embraer. The company reported here yesterday that it had completed the joint definition phase for both aircraft, a critical milestone leading to the detailed design and certification phase of the programme.

Honeywell's largest contribution to the new Legacy will be the 7,500lb-thrust (33kN) HTF7500E turbofan engines, derivatives of the company's HTF7000 family engines that have been flying on the Bombardier Challenger 300 since early 2004.

The HTF7250G was selected by Gulfstream to power the G250, set for first flight by the end of the year. Honeywell designed the HTF7000 propulsion family to be an integrated package featuring the engine, nacelle and reversethruster.

With 500 engines delivered and 500,000h of flight time, Honeywell reports an industry-leading dispatch reliability of 99.96 for the powerplant based on the Challenger 300 fleet.

A major innovation for Embraer over both Gulfstream and Bombardier is the way the engine will mount to the airframe. While engines are traditionally hard-mounted to the pylon at the front of the engine, with the bulk of the engine's weight cantilevered from that point, Honeywell's new "structural bypass" mounting method will use a tightly toleranced duct around a larger portion of the engine. This spreads theload over a larger area of pylon and actslike a damper of sorts, says TK Kallenbach, Honeywell's vice-president of marketing and project management.

While challenging in terms of designing a system that will maintain the tight tolerance, the technology should pay off with lower fuel consumption, lower weight and better balancing. Kallenbach notes that better balancing also means less vibration will be transmitted to the cabin, easing the ride and wear and tear on the aircraft structure.

Source: Flight Daily News