Conceptual design of sonic boom stealth supersonic transports

This paper introduces a supersonic transport aircraft design model developed in the GENUS aircraft conceptual design environment. A conceptual design model appropriate to supersonic transports with low-to-medium-fidelity methods are developed in GENUS. With this model, the authors reveal the relationship between the sonic boom signature and the lift and volume distributions and the possibility to optimise the lift distribution and volume distribution together so that they can cancel each other at some region. A new inspiring design concept—sonic boom stealth is proposed by the authors. The sonic boom stealth concept is expected to inspire the supersonic aircraft designers to design low-boom concepts through aircraft shaping and to achieve low ground impacts. A family of different classes of supersonic aircraft, including a single-seat supersonic demonstrator (0.47 psf), a 10-passenger supersonic business jet (0.90 psf) and a 50-seat supersonic airliner (1.02 psf), are designed to demonstrate the sonic boom stealth design principles. Although, there are challenges to balance the volume with packaging and control requirements, these concepts prove the feasibility of low-boom low-drag design for supersonic transports from a multidisciplinary perspective.

An efficient decision support system for selecting very light business jet using CRITIC-TOPSIS method

Purpose This paper aims to assure the selection of the most suitable very light business aircraft which is preferred by the passengers based on effectiveness and aesthetic comfort. The proposed approach to determine the light business jet aircraft would provide long-range, less travel time, cozy seating arrangements, on-board lavatory facility, other aesthetic ambiance (audio systems, light systems and temperature-noise control) and appliances at reasonable flight cost. Design/methodology/approach The selection of a light business jet is obtained through multi-criteria decision-making based on the speed limit ranges from 0.57 to 0.70 Mach number and the distance traveled up to 3,000 km with the best aesthetic comfort level. To validate the approach, case studies of five aircrafts such as Honda Jet HA 420, Cessna Citation jet M2, Embraer Phenom 100, Eclipse 550 and Cessna Citation Mustang are performed. To obtain the best suitable business jet, criteria importance through intercriteria correlation (CRITIC) and technique for order performance by similarity to ideal solution (TOPSIS) is used to determine the rankings of listed aircraft. Findings The study concludes that the Cessna Citation jet M2 is chosen as the best Very Light Jet (VLJ) on the basis of speed, range, weight, cost, aesthetic and comfort. Based on the sensitivity, mean absolute percentage error (MAPE) and symmetric mean absolute percentage error analysis (sMAPE), the most and least sensitive criteria for a business jet came out to be cost and speed, respectively. Originality/value A real case study for several parameters of five different jets such as Honda Jet HA 420, Cessna Citation jet M2, Embraer Phenom 100, Eclipse 550 and Cessna Citation Mustang are shown in this paper. Based on the case study numerical values are assigned with speed, range, weight, cost, aesthetic and comfort which are applied with CRITIC and TOPSIS to obtain the most suitable business jet among the five mentioned jets which are rarely found in the literature.

Prioritized optimization by Nash games : towards an adaptive multi-objective strategy

This work is part of the development of a two-phase multi-objective differentiable optimization method. The first phase is classical: it corresponds to the optimization of a set of primary cost functions, subject to nonlinear equality constraints, and it yields at least one known Pareto-optimal solution xA*. This study focuses on the second phase, which is introduced to permit to reduce another set of cost functions, considered as secondary, by the determination of a continuum of Nash equilibria, {x̅ε} (ε≥ 0), in a way such that: firstly, x̅0=xA* (compatibility), and secondly, for ε sufficiently small, the Pareto-optimality condition of the primary cost functions remains O(ε2), whereas the secondary cost functions are linearly decreasing functions of ε. The theoretical results are recalled and the method is applied numerically to a Super-Sonic Business Jet (SSBJ) sizing problem to optimize the flight performance.

Aircraft repair damage tolerance analysis

Modern air travel has become a perpetual evolution both from a practical and scientific point of view. However, it is also becoming increasingly common to fly in an airplane with little or no regard for the immense engineering involvement that goes into making air travel as safe and efficient as possible. This report considers the problems of aircraft fatigue and how it translates to inspectability for safety in order to predict problems and solve them before they actually occur. The most common aircraft repair is a crack in a pressurized skin panel. This report evaluates the structural integrity of a particular panel that is assumed to have failed in service and thus been repaired by the addition of a doubler. Damage tolerance analysis is used to evaluate a conservative crack growth scenario for a typical business jet with a structural economic life of 15,000 flight hours. The step shown follow the guidelines approved by the regulating aviation bodies of both Canada and the United States (Transport Canada and the FAA respectively). Structural inspections are a common practice for aircraft at their half lives; in this case it would be 7,500 flights. The report determines that this particular scenario defines a threshold inspection interval of 8,414 flights and a repeat of 2,944 flights thereafter. In comparison with an actual test aircraft, having experienced an almost identical failure and repair program, the test aircraft experienced failure at 9,963 flights. Therefore, the intervals presented herein provide adequate clearance for the detection and repair of such damage. The purpose of this report is to introduce the underlying principals of damage tolerance analysis to the reader and illustrate the analytical process with a real world example. Such is the job of an aerospace stress engineer.