Gary Coleman

What Price Supersonic Speed? - A Design Anatomy of Supersonic Transportation - Part 1

The first generation of supersonic commercial transportation has seen three serious attempts to arrive at an economically and environmentally viable aircraft. The US B2707-200/300 design was cancelled early before a prototype could emerge; the Russian Tu-144 design succeeded to become the first supersonic transport but spanned only a few years of restricted airline service; the Anglo-French Concorde endured more than 27 glamorous airline service years until the last of its species was retired on 30 August 2003. This first generation was followed by a second generation of supersonic commercial transport projects in the time period between 1986 until about 1999, designs which did not proceed towards the production hardware stage. This study critically examines the anatomy of two generations of supersonic commercial transport design failures and successes in order to arrive at lessons learned free of ‘wishful thinking’. The design conditions leading to the identification of the product ‘solution space’ for an economically and environmentally acceptable supersonic commercial transport are discussed. Having assembled an understanding of the product metrics valid for supersonic commercial transports, the paper then provides an outlook for the first generation of supersonic corporate and cargo jet projects. This first generation of supersonic business jet (SSBJ) and supersonic cargo jet (SSCJ) projects spans a period of nearly two decades of development, starting from 1988 until today. The present study identifies that the product development metrics of this class of aircraft is radically different compared to the metrics valid for supersonic commercial transports. The challenges in VIP transportation and dedicated freight transportation at supersonic speeds are portrayed leading to two principal trains of thought targeting the development of the first supersonic business jet and/or supersonic cargo jet hardware: the development based on a new airframe, and alternatively the development based on an existing airframe.

A Generic Hands-On Conceptual Design Methodology Applied to a Tourist Space Access Vehicle

*† ‡ The present study summarizes the development steps required towards a generic (configuration independent) hands-on flight vehicle conceptual design synthesis methodology. This process is developed such that it can be applied to any flight vehicle class if desired. In the present context, the methodology has been put into operation for the conceptual design of a tourist Space Access Vehicle (SAV). The case study illustrates elements of the design methodology & algorithm for the class of Horizontal Takeoff and Horizontal Landing (HTHL) SAVs. The HTHL SAV design application clearly outlines how the conceptual design process can be centrally organized, executed and documented with focus on design transparency, physical understanding and the capability to reproduce results. This approach offers the project lead and creative design team a management process and tool which iteratively refines the individual design logic chosen, leading to mature design methods and algorithms. As illustrated, the HTHL SAV hands-on design methodology offers growth potential in that the same methodology can be continually updated and extended to other SAVs configuration concepts, such as the Vertical Takeoff and Vertical Landing (VTVL) SAV class. Having developed, validated and calibrated the methodology for HTHL designs in the ‘hands-on’ mode, the paper provides an outlook how the methodology will be integrated into a prototype computerized synthesis design software AVDS-PrADO SAV as a follow-on step.

Feasibility study of a supersonic business jet based on the Learjet airframe

Since the dawn of the jet age, passengers on all jet transports, except Concorde, have traveled at about the same speed — a standard Mach 0 83-0 87 range as a practical compromise. After 27 years of supersonic commercial travel, British Airways and Air France retired their fleet of Concorde aircraft at the end of 2003 because it was considered no longer profitable. Clearly, with the retirement of Concorde, the world has lost the only aircraft offering passenger transportation at supersonic speeds. Over the past several years manufacturers have proposed new aircraft designs that promise an increase in transportation speeds. In particular, the business jet market appears to present a business case for an exclusive supersonic business jet (SSBJ). However, there is a key-hurdle which has, until now, prevented the successful launch of a SSBJ hardware program: the development cost for an all-new aircraft quickly eradicates the soughtafter business case. This paper presents the results of a parametric sizing study which aims to answer the following question: is it possible to drastically reduce the development effort of a supersonic business jet design by converting an existing Learjet airframe into a supersonic vehicle while sustaining FAA interest and approval? This paper discusses selected aircraft sizing trades and operations related constraints. The feasibility study indicates some level of technical plausibility for the case of converting an existing airframe into a certifiable lower-cost supersonic aircraft. Acknowledging the range of actual complications related to the task of economically modifying and certifying a legacy airframe towards a SSBJ, it appears that a larger size SSBJ offers significant technical and economical advantages which outweigh the ‘off-the-shelf’ Learjet case.

Generic stability and control for aerospace flight vehicle conceptual design

The recent period has been filled with exceptionally interesting developments and advances, resulting in high-performance conventional and non-conventional manned and unmanned aircraft. Although those vehicles seem to comply well with specific mission performance requirements, one is still confronted with an apparent weakness to reliably stabilise and control throughout the flight envelope. Since the provision of satisfactory stability and control characteristics invariably compromises flight performance, it becomes essential to identify and integrate performance-optimal stability and control design solutions early during the flight vehicle definition phase. In particular, the conceptual design of integrated control effectors for advanced aircraft is far from being trivial. Never before have we been presented with such tremendous wealth of specialised data and information suitable for detail design of controls. In contrast, never before has it been necessary to approach any one of the primary design disciplines still as entirely ad hoc and inconsistent as in the case of designing controls during the conceptual design phase. This need initiated the development of a configuration independent (generic) stability and control methodology capable of sizing primary control effectors of fixed wing subsonic to hypersonic designs of conventional and unconventional, symmetric and asymmetric configuration layouts. This paper summarises the methodology concept and demonstrates its versatility and validity by analyzing selected stability and control characteristics of the Northrop YB-49 flying wing.

A Generic Stability and Control Tool for Conceptual Design: Prototype System Overview

Aerospace conceptual designers are typically tasked to explore and size various vehicle concepts for a particular mission and then make the best decision possible for the vehicle’s initial configuration. This can be a daunting task due to a lack of information and design tools to adequately analyze, size, and compare dramatically different configurations. From the standpoint of available tools, an array of options are available for aerodynamics, structure, propulsion, and other individual disciplines, but a serious lack of tools exists for stability and control. Typically, stability and control at the conceptual design level is done through the use of statistical volume coefficients and reduced order models. These, however, are not always applicable for configurations other than classical tail aft configurations (TAC). Thus, a clear need for a more generic tool exists. This need has led to the development of AeroMech, a generic stability and control tool for conceptual design. This paper discusses the prototype, stand-alone system of AeroMech and demonstrates the tool’s applications through an example validation case study, The Northrop YB-49 Flying Wing.

Technology and operational sensitivity assessment for hypersonic endurance flight vehicles

In an effort to increase the air-breathing endurance capability of current hypersonic research aircraft (i.e. X-43, 7 seconds; X-51, 5 minutes), the authors have explored the technical and operational solution space for a 30 minute cruise endurance demonstrator operating in the Mach 6 to Mach 8 speed regime. The focus of this activity has been on exploration of the available solution space through a unique screening process to assess the implication and interplay between the (a) mission, (b) baseline vehicle, and (c) operational scenarios. This study concludes that an air-launched, liquid hydrogen fuelled, 30 minute duration Mach 6 demonstrator (with 10 min Mach 8 capability) provides the largest feasible solution space of the trades examined (i.e. largest design margins, lowest technical risk) when compared to a kerosene-powered equivalent.

Novel Senior Design Approach of a Hydrogen Citation X

A unique approach to the design of hydrogen fueled business jet taken by the senior aerospace design class, at the University of Texas at Arlington. The class was divided into two teams Maverick Aircraft Concepts and MavWorks held in creative isolation from each other resulting in similar analysis methods, but a drastic difference in design philosophy. In the context of this educational project, emphasis has been placed on true multi-disciplinary integration of all team members and their respective disciplinary analysis responsibilities throughout the project period. Focus has been on the initial vehicle sizing phase, requiring all team members to first develop and then to integrate their respective analysis tools into a custom-builtconceptual design methodology. Overall aim has been to arrive at a numerical total systems convergence assessment, a requirement which is usually beyond the predominantly analysis oriented senior design capstone project expectation. The overall synthesis assessment consists of pre-phase (PP), parametric sizing (PS), configuration layout (CL), and configuration evaluation (CE) activities. Using the developed methodology, a unique integrated sizing methodology introduces the student team members to true multidisciplinary technical trades and coordinated team interactions. The approach chosen illuminates the unexplored potential of converting an existing business jet into a hydrogen powered executive aircraft equivalent. This paper demonstrates the process Maverick Aircraft Conceptsemployed to design a hydrogen powered Citation X.