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A personal computer based preliminary design system for aircraft demonstrates a practical method to design and analyze any aircraft configuration. The program provides a powerful framework to support the non-unique process of aircraft preliminary design. The system will allow design engineers to rapidly evolve an aircraft configuration from weight sizing through detailed performance calculations, while working within regulatory constraints. The program is designed to reduce the preliminary design phase cost and to bring advanced design methods to small businesses and universities.

An advanced, unconventional two-engine jet configuration shows considerable promise of significantly reducing operating costs, dramatically improving two-engine climb performance, extending range and increasing safety.

A user-friendly method for analyzing longitudinal and lateral-directional trim problems for airplanes with all engines operating (AEO) and with one engine inoperative (OEI) is presented. The method allows for rapid evaluation of various critical handling qiality parameters, such as stick-force per ‘g’ and stick-force versus speed gradients. In addtion, the effect of failures in trim systems on cockpit control forces and on control surface and/or tab deflections can be assessed. Also, the method can be used for sizing of tab control systems, down-springs, bob-weights and interconnect springs. Finally, elevator hingemoment derivatives for rather arbitrary aerodynamic balance configurations can be quickly estimated.

A preliminary design study is conducted of three very long range business jets. One has two engines mounted on the rear fuselage, like most existing business jets. The other two have two or four engines mounted under the wing. The paper shows that the design takeoff weight of very long range business jets is extremely sensitive to three parameters: design range, design sfc and design L/D. Depending on the design range and wing loading, these airplanes are also critical in terms of available fuel volume. The paper gives an analysis of the pros and cons of either configuration. A cost comparison in terms of DOC (Direct Operating Cost) is also given. When considering both cost and takeoff weight, the 2-engines-under-the-wing design is shown to come out on top.

The design and recovery considerations are presented for a staged supersonic transport (SSST). It is shown that the SSST offers economic benefits over the conventional SST. The SSST benefits from the ability to “optimize” the design for minimum drag during supersonic cruise without the penalties of: landing gear, extensive flaps for landing, and the meeting of FAR 36 noise requirements. The recovery considerations are also presented to validate the SSST concept.

Air travelers between medium sized coastal cities in the USA are faced with a major inconvenience: they are forced by existing airline schedules to make at least one stop in a major hub with a change of airplane and, sometimes even a change in air carrier. This inconvenience translates into lost time, missing of a connection due to delays and possible loss of luggage. These inconveniences could be alleviated if non-stop, coast-to-coast small jet commuters could be designed such that they can compete with the existing transcontinental transports on a DOC per passenger seat-mile basis. It is shown that significant advances in aerodynamic and propulsion design technology will be needed to enable the profitable development of such airplanes.

The preliminary design studies are presented for an advanced general aviation aircraft. Advanced guidance and display concepts, laminar flow, smart structures, fuselage and wing structural design and manufacturing, and preliminary configuration design are topics to be discussed. This project was conducted as a graduate level design class under the auspices of the KU/NASA/USRA Advanced Design Program in Aeronautics. This paper will present the results obtained during the fall semester of 1990. The project will be continued into the spring semester of 1991.

The paper demonstrates the importance of design and design-integration teaching at the university level. Specific topics which should be taught to equip aerospace engineering students with essential design integration skills are presented. The motivation behind this paper is threefold: 1) the large amount of costly design mistakes made during the last two decades 2) the strong trend in the aerospace industry toward ‘TOTAL ENGINEERING’ 3) the poor quality and quantity of design education in universities

An economic analysis is presented of a composite (= staged) configuration option to a supersonic transport with transatlantic range. It is shown that the staged approach offers economic advantages over a conventional SST. A staged SST offers the possibility of ‘optimizing’ the configuration for the cruise flight condition, does not require flaps nor landing gear, does not carry any penalty for meeting FAR 36 takeoff and landing noise requirements and causes up to 30% less stratospheric pollution. Therefore, despite the potential for operational problems with launch and recovery, the staged SST option may have to be taken seriously.

The University of Kansas, Flight Research Laboratory is developing an interactive, user-friendly computer program to perform preliminary design and analysis functions for fixed wing airplanes. This paper presents a discussion of the current status of this program. Use of the program is illustrated with an example application to an advanced stealth bomber.

This paper presents examples of how severe and/or novel design requirements can ‘drive’ an airplane designer to select a ‘unique’ configuration. Examples to illustrate this are given for the flying wing, for two- and for three-surface canards and for joined wing airplane configurations. Brief historical reviews are also provided.

This paper describes work done under a NASA-Langley grant at the university of Kansas Flight Research Laboratory in the area of natural laminar flow and regional aircraft. The focus of this paper is on the application of natural laminar flow over various major wetted areas. In particular, efforts were concentrated on analyzing the potential benefits of achieving extensive laminar flow on the wing, empennage, and fuselage. The effect of the presence of large amounts of laminar flow is evaluated in terms of performance and efficiency improvement over an all-turbulent baseline aircraft. An introduction is given to the concept of regional aircraft, and the aerodynamic characteristics are compared to those of other airplane classes. Some recent aerodynamic developments are presented that justify, to a certain extent, the assumptions made concerning the amount of natural laminar flow that is possible for each surface.

Since the entry of ultralight aircraft into the market in 1975, many changes have come about. With these changes, questions have arisen regarding the overall safety of these vehicles. This paper will show preliminary results of tests conducted to obtain an overall data base of a typical ultralight aircraft. These tests were conducted on an Airmass Sunburst Ultralight Model ‘C’ and include results from an experimental weight and balance as well as a theoretical drag analysis. The data base is viewed only as a starting point for allowing the ultralight industry to better understand the true characteristics exhibited by typical ultralight aircraft. This would allow for the design of safe ultralights under the current voluntary self-regulation program or any future programs that might be developed.

The results of a design investigation of some unconventional airplane configurations are reported in this paper. The viability of designing canard and 3-surface airplanes to meet commuter airline needs was investigated. This study was conducted on an airplane designed to carry 30 passengers on 600 n.m. stage lengths, cruising at 0.6 Mach number at an altitude of 28,000 feet. A test ride quality evaluation was also carried out. This indicated that, although considerable performance improvement was possible over existing airplanes of the same type, active ride augmentation systems were needed to achieve airliner levels of comfort. All three airplanes looked good in terms of mission fuel consumption and climb terms. The 3-surface configuration managed to edge out the other two in those same terms.

This paper presents the results of an investigation into the design of advanced commuter configurations. The airplanes were required to carry 30 passengers over a 600 n.m. stage length at a cruise Mach number of 0.6 at an altitude of 28000 feet. The airplanes were required to have inherent static stability. Five unconventional twin turboprop configurations were investigated. These consisted of three canard and two 3-surface configurations. To provide separation of passengers and crew from the plane of the propellers and engine turbine and compressor discs, aft-mounted pusher-propeller configurations were adopted. This also resulted in a saving in the amount of sound proofing (weight). High wing loading was chosen to reduce wetted area and achieve good ride qualities. The combination of high wing loading and the required inherent static stability made it extremely difficult to realize canard configurations.

This paper describes a simple, self-contained flight test data acquisition system. The system makes use of the latest sensor and microprocessor technology available, to reduce overall system costs. Coupled with this is the use of modern control theory techniques allowing minimization of data requirements, as well as flight time requirements. Capability of the system includes primarily stability and performance analysis of general aviation airplanes, although system versatility has been designed into the package. Presented are details of the prototype system constructed, as well as details of the data reduction technique utilized. Preliminary results of the flight test program have also been included which demonstrate the capability of this system.

The paper presents the results of a study performed under contract with NASA-Langley Research Center to document the state of the art of general aviation (GA) autopilots. The study was conducted to provide NASA-Langley with fundamental, background information about the current status of general aviation autopilot technology. The information presented is based on findings obtained from a general literature search, product literature, visitations and interviews with manufacturers, users, and service centers. Recommendations concerning potential areas of further research are also presented.

Based on recent work by DARPA (Defense Advanced Research Projects Agency) it is shown that forward swept wings have several advantages over conventionally aft swept wings. By combining the forward swept wing with both a canard and a horizontal tail configurations emerge with interesting possibilities.

This paper describes the design of an advanced, four-place business jet airplane around two Williams-Research WR-19 engines. In addition to the general layout, the performance, weight and balance characteristics of the airplane are described and illustrated by graphical examples. A detailed comparison in terms of fuel-used is made with the Learjet M35, the Cessna Citation I, the Foxjet and several other general aviation twins. It is shown that the airplane described offers substantial advantages in terms of fuel economy over all these airplanes.

The paper summarises the work done by the University of Kansas Flight Research Laboratory on separate surface control systems. Theory, potential applications and a summary of the state-of-the-art of separate flight control technology are discussed.