Growing air travel, with its associated environmental impact, is increasingly becoming a public concern. The laminar flying wing (LFW), which utilises boundary layer suction as a means of laminar flow control, has been proposed by Greener by Design as a potential solution, with preliminary estimates suggesting a significant reduction in fuel-burn. The purpose of this study is to investigate whether a conceptual design which supports this assertion can be produced. The starting point is to end the overall size, cruise speed and cruise altitude that satisfy constraints imposed by the LFW configuration: subcritical ow, limited by Reynolds number, eficient ight and satisfactory passenger accommodation. By treating the aircraft as an unswept 'ying plank', we find that a maximum section thickness-to-chord ratio of 28 %, a chord length of 8.9 m, a span of 80 m, along with a cruise Mach number of 0.58 at an altitude of 10900 m and a cruise weight of 69 tonnes, meet these demands. A planform and section geometries are then developed to allow an estimate of the suction required to maintain laminar ow; this is 20.7 kgs-1, requiring 625 kW of power. The associated cruise thrust is 7.6 kN; the engine is designed to provide this plus the off-take to power the suction system and auxiliary components. The resulting specific fuel consumption is 18.4 g/kN.s. The structural weight is estimated via standard preliminary design methods for a metal aircraft, and is 30.5 tonnes. With the operating empty weight determined, and 32.2 tonnes allowed for fixments, passengers (120) and baggage, 6.3 tonnes is left available for cruise fuel; on the basis that 5.2 tonnes is usable, this gives a 4125 nm range at a fuel-burn of 6 g/pax.km. The longitudinal static stability of the design remains an issue: the estimated centre-of-gravity range implies that a feedback control system would be required.
Conceptual design for a laminar flying wing aircraft
Konzeptueller Enwurf für ein Flugzeug mit Laminarflügel
AIAA Applied Aerodynamics Conference, 27 ; 2009/3616-2009/28
2009
28 Seiten, 28 Quellen
Conference paper
English
Conceptual Design for a Laminar Flying Wing Aircraft
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