International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:15 No:06 37 153306-4848-IJET-IJENS © December 2015 IJENS I J E N S Abstract— Anticipating potentialair transportation markets in the business jet type, the present work is devoted for exploring the possibilities of introducing some of a number of visionary and pioneering ideas and upcoming enabling technologies in the Aerodynamic and Conceptual Design Study of Quad-Bubble Business Jet (QB-BJ). In view of and driven by the vision for a fuel efficient, environmentally friendly and technology driven aircraft to meet global need within the next 15 years, the characteristics of the conceptually designed aircraft will be assessed in comparison to an appropriately chosen business jet as a reference. Major ideas derived from D8 are appropriately applied in the work, which starts with fuel efficient motivation, and followed by wing Aerodynamics and other critical factors related to the Design Requirements and Objectives. Index Term— Aircraft Conceptual Design, Double-Bubble Business Jet, Quad-Bubble Business Jet, Applied Aerodynamics. I. INTRODUCTION Vision for a fuel efficient, environmentally friendly and performance and technology driven aircraft to meet global need and N+ 3 goal-setting within the next 15 years have been recently developed or proposed in progression [1-4]; the most attractive of these novel transport aircrafts are the Blended- Wing-Body, Joined-Wing and Double-Bubble Wing configurations. The latter configuration concept has also been developed to address needs and anticipate available enabling technologies progressive for three successive periods up to 2030. Realizing that the upcoming air transportation markets in the business jet type are also potential, the present work is devoted for exploring the possibilities of introducing some of a number of visionary and pioneering ideas and upcoming enabling technologies in a Conceptual Design Study of Quad- Bubble Business Jet, which is inspired by Double-Bubble (D.8) [1,2,3,4,5,6] configuration, and assess its characteristics in comparison to an appropriately chosen business jet as a reference. The term Quad-Bubble is adopted here since essentially, among the technologically developed fuselage configurations, the selected fuselage cross section has the quad-bubble features. Major ideas derived from N+3 aircraft technologies, which have been incorporated and translated Harijono Djojodihardjo was with Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia. He is now the President of the Institution for the Advancement of Aerospace Science and Technology, Jakarta 15419, Indonesia. (e-mail: harijono.djojodihardjo@yahoo.com; harijono.djojodihardjo@gmail.com). Mohammad Anas Abd Bari is a PhD student at the Aerodynamics & Flight Mechanics Research Group, University of Southampton, Southampton SO17 1BJ, UK into D.8 concept introduced by Drela, will be selectively applied as appropriate and further elaborated in the Conceptual Design Study of a Quad-Bubble Business Jet. The Conceptual Design and Aerodynamic Study of Quad-Bubble Business Jet (QB-BJ) is carried out focusing on its Aerodynamics which includes Wing Planform Configuration and profiles, and their relationship to the Design Requirements and Objectives. Possible Configuration Variants, Mission profile, Flight Envelope requirements, performance, stability, as well as the influence of propulsion configuration of QB-BJ aircrafts are considered and elaborated. Parametric study is performed on wing planform, thickness, and twist optimization, with design variables including overall span plus chord, sweep, thickness, and twist at several stations along the span of the wing prior to more structured optimization scheme. Considerations are also given to range, maximum lift, stability, control power, weight and balance. A statistical study and review on prevailing market demand leads to the choice of conventional Subsonic Business Jet candidate, which will be used as a Reference Conventional Business Jet (RC-BJ) for the aerodynamic and configuration of the conceptual design of QB-BJ. The chosen business jet accommodates 18 passengers as a baseline. Some aerodynamic and performance improvement is then carried out through parametric study to arrive at the best solution meeting the design requirements and objectives. Particular attention has been given to identify and adopt concepts and technologies needed for reduction in fuel per passenger-mile from current technology baseline that may be available by 2035, and the adaptation of Drela's [1,2,3] wide “double-bubble” fuselage with beneficial pitching moment and carryover lift characteristics and high Aspect Ratio nearly- unswept laminar wing. Other factors which have been identified to be necessary for achieving N+3 goals are reviewed, selected and utilized, such as the reduction of secondary structure weight, the twin “pi-tail” configuration similar to that utilized for wing-mounted engines; at the present stage, conventional high efficiency engine with the appropriate choice of high bypass ratio will be utilized. Cruise velocity and altitude will be optimized commensurate with environmental requirements for ten to twenty years to come [7, 8, 9, 10,11]. Considering cruise altitude acceptable by environmental regulation, cruise velocity for 10 years to come can be assumed to be the same as at present, i.e. M = 0.8 and altitude between 33000 to 40000ft [12]. The merit of each feature is evaluated in terms of mission fuel burn. The choice of wing profile and fuselage is carried out selectively, first by comparing their characteristics as specified and referring to Quad-Bubble- Business Jet Aerodynamic and Conceptual Design Study Harijono Djojodihardjo and Mohammad Anas Abd Bari