It has been more than 10 years since a new Learjet platform was introduced to the general aviation market. Now, Bombardier has unveiled details of its forthcoming Learjet 85 that promises to fly faster and further than any of its predecessors - and its flawless design is fused with the latest technologies on the market.
Upon its highly anticipated release in 2013, the Learjet 85 will be the first mid-range business jet to be built primarily from carbon composites and designed for type certification under the US Federal Aviation Regulation.
Ralph Acs, vice-president of Learjet 85 at Bombardier Business Aircraft believes the company’s ‘clean-sheet’ approach of replacing traditional aluminium structures with carbon fibre composites will revolutionise the industry.
Acs says: “Sometimes you may need three or more parts if you are constructing something out of metal and then you have to fasten parts together. With composites you are able to mould parts very differently. And therein lies the difference.”
Design structure
The pressurised fuselage section, which extends from the cockpit to the pressure bulkhead, is produced using a low pressure, oven-cured, out-of-autoclave carbon fibre supplied by Cytec Engineered Materials.
In a metallic aircraft, this part would be made out of hundreds of pieces but with the carbon fibre design it is a single piece.
In total, Bombardier has been able to reduce the overall fastner count by an extraordinary 70 percent as a result of fewer parts being needed to be joined.
The composite structure of Learjet will now increase passenger comfort by allowing for the use of complex curves in the aircraft’s internal cross-section and thinner wall thickness to maximise cabin volume.
“Designing in composites requires a different design mentality,” elaborates Acs. “The engineering and the manufacturing of composites go hand-in-hand. You design it, make it, tweak it and then try it all over again. In the end, what we want is a simple and repeatable manufacturing process.”
The ability to design a structure with fewer parts and fastners helps reduce unit costs, which has been a key driver in the company’s switch to using carbon fibre.
“By having a more economic unit cost we are able to add some of the features requested by our customer focus groups, such as auto-throttle and nose wheel steering, which are not typically found in a business jet of this size,” says Acs.
In addition to improving performance and minimising drag through smoother aerodynamics, the composite airframe will also require less maintenance besides being easier to repair and have an extended service life.
Comfort and style
The design goals of the Learjet85 have been heavily influenced by its three customer focus groups, which are made up of between 15 and 20 customers. These groups have focussed closely on the cockpit, interior of the aircraft and maintenance, offering creative input on every detail - from the layout of the galley to the positioning of cup holders and light switches.
The Learjet 85 cabin provides a larger and more comfortable space than current jets in the midsize market. Consisting of 14 large windows, the cabin has a maximum height of 5ft 11 inches and a maximum width of 6ft 1inch.
The aircraft, with a maximum capacity for eight passengers and two crew members, is fitted with the latest technology and some great luxuries.
“From nose to tail, the Learjet 85 aircraft remains true to Learjet’s commitment to innovation by integrating the latest in technological advances with superior design aesthetic,” says Acs.
“The aircraft features the latest technology in its advanced entertainment system, which offers passengers optimal features. These include a DVD player, HD bulkhead monitors, XM satellite radio capabilities and internet access.”
The aircraft galley is 36 inches wide and provides room for tableware as well as drink and ice storage. It can also accommodate an optional microwave oven. Passengers are encouraged to relax onboard with fully reclinable seats and personalised Light Emitting Diode (LED) lighting, which includes individual table lighting and reading lights.
Flight height
The Learjet85 flies 49,000 feet, compared to the 36,000 feet of commercial aircraft.
"The real innovative thing we have done is to push down the cabin altitude as low as we can," says Acs. “This means the cabin itself where the passenger is sitting experiences just 6,000 feet. The lower the cabin altitude that the person is feeling, the more rested and comfortable they ... Read the rest: http://www.manufacturingdigital.com/industry-focus/world-class-operations/learjet-85-innovation-aviation
