Browsing by Author "Field, Edmund"

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    The application of a C* flight control law to large civil transport aircraft
    (1993) Field, Edmund
    The work contained in this report is part of an on-going programme of research into handling qualities of fly-by-wire civil transport aircraft currently being undertaken within the Flight Dynamics Group of the College of Aeronautics . Although much work has been undertaken into handling qualities of military aircraft over the last 30 years, civil aircraft have received considerably less attention. Over the last decade civil transport aircraft incorporating fly-by-wire flight control systems have been introduced into commercial operation, the latest including some modified aerodynamic designs. However the civil arena lacks the supporting research into handling qualities that the military side has enjoyed. More recently the civil side is beginning to receive the attention it deserves with work in Europe by Fokker and the Group for Aeronautical Research and Technology in EURope (GARTEUR), for example. In the United States much work has been done by the manufacturers such as Boeing and McDonnell Douglas, and as ever work supported by the US Air Force and NASA. The primary aim of this current programme is to design flight control laws to give fly-by-wire civil transport aircraft excellent flying qualities at all flight conditions, but especially in piloted flight phases. The most critical flight phase of a civil transport is that of the landing approach, and, as with other studies of this type, this phase receives the greatest attention in this study. This report concerns an analysis of the C* parameter. The C* criterion was one of the first handling qualities criteria designed to take account of advanced aerodynamic designs of modern aircraft and higher order systems introduced by flight control systems. Several aircraft have since employed control laws based around the C* parameter. A proportional feedback C* controller was applied to a Boeing 747-100 in landing approach configuration, and assessed against the C* criterion and the US military specification MIL-STD- 1797A.
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    Flying qualities of transport aircraft : precognitive or compensatory?
    (Cranfield University, 1995-06) Field, Edmund; Cook, M. V.
    The introduction of fly-by-wire electronic flight control systems into transport aircraft has given the flying qualities engineer the opportunity to optimise the flying qualities of these aircraft for their specific tasks. With this technology has come the opportunity to introduce new technologies into the cockpit, such as non-linked or backfed sidesticks and non-backfed throttle levers. A comparative survey of airline pilots flying such a very high technology unconventional aircraft and a high technology but conventional aircraft suggests that these technologies may reduce the available channels of communication to the pilot in the very high technology aircraft, resulting in the possibility of reduced situational awareness. A closed loop piloted simulation survey of ten transport aircraft in current operation was undertaken which demonstrated that they all suffered from flying qualities deficiencies, limiting the performance that the pilot could achieve. In particular poor dynamics precluded the pilot adopting tight closed loop, or compensatory, control. Instead it was necessary to adopt a more open loop, precognitive, technique with medium frequency modulation, resulting in a degradation in landing performance. Through appropriate flight control system design it should be possible to produce aircraft that can be flown using the full range of control inputs from open to closed loop. The major study of this thesis assessed, through piloted simulation evaluations, the suitability of a wide range of longitudinal commanded response types for the approach and landing tasks. It was concluded that a response type that closely resembles that of angle of attack is optimum for these tasks due to its conventional characteristics of speed stability on the approach and monotonic stick forces in the flare. Such a system, appropriately implemented, should allow the transport aircraft pilot the full range of piloted control inputs, from open loop, precognitive, to closed loop, compensatory, resulting in improved landing performance.
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    A piloted simulation investigation of several command concepts for transport aircraft in the approach and landing
    (1994) Field, Edmund
    With the introduction of modern fly-by-wire aircraft, the response of an aircraft to a pilot’s input can be augmented to something other than that for a conventional aircraft, with the resultant benefits and problems. The issue of what commanded response a pilot desires has received considerable attention, however no clear conclusions have yet emerged. The requirements for up and away flight and for the flare and landing seem to be different. Away from the ground rate command systems such as pitch rate and flight path rate seem to be well received for their low pilot workload associated with the control of flight path. However in the flare and touchdown these systems exhibit unnatural floating tendencies, requiring the pilot to push forward on the stick to land the aircraft. As a result most fly-by-wire aircraft incorporate separate up and away control laws and flare laws. This investigation is designed to consolidate on the work achieved by many organisations over the past ten years and concentrate on pilots’ preferences for the final stages of the approach and into the flare and touchdown. Twenty nine different flight control law configurations were designed for a regional sized aircraft. These configurations concentrated on several different command philosophies designed to investigate the pilots’ preferred command parameter and covered three different centre of gravity locations. These configurations were then implemented on the fixed base engineering simulator at British Aerospace Regional Aircraft, Hatfield, and evaluated by four test pilots.
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    Report on a visit to the Arvin/Calspan Corporation Buffalo, New York, September 1992
    (1993) Field, Edmund
    The visit to the Arvin Calspan Corporation in Buffalo was made in support of a PhD programme undertaken in the College of Aeronautics (CoA). the research topic concerns flying and handling qualities of advanced fly-by-wire civil aircraft. With the introduction of electronic Flight Control Systems (FCS) the responses of aircraft to a pilot input can become highly modified compared with that of conventional aircraft. As such systems have been introduced to military aircraft problems associated with their flying and handling qualities have become apparent. Much research and development work has been undertaken into understanding and solving these problems and producing military aircraft that handle well. Although this work continues, today’s aircraft demonstrate a vast improvement on earlier designs. While much research has been undertaken into the flying and handling qualities of military aircraft considerably less has been performed in the area of civil aircraft. Consequently there are few guidelines for the design, assessment and certification of the civil aircraft now being produced that utilise electronic FCS. The purpose of this PhD programme is to address the deficiencies in the civil aircraft field and apply the knowledge and technologies of the military designs and criteria where applicable. In order to do this it is necessary to obtain a thorough understanding of the work undertaken in both the military and civil fields, and to gain exposure to problems that have been identified. The Arvin/Calspan Corporation has been involved in handling qualities research since the 1940’s and through it’s numerous research programmes utilising it’s variable stability aircraft has become recognised as one of the world leaders in the field of handling qualities. Therefore a visit to the headquarters of the Flight Research Department of the Arvin/Calspan Corporation in Buffalo was made in support of this study. The two main purposes were to undertake a literature search of their reports from their research programmes of relevance to this study and to perform an engineering test flight in one of their two Variable Stability Learjet In-Flight Simulators, to demonstrate features of modern FCS designs. During the visit the opportunity was also taken to discuss the more recent developments in the field with Calspan personnel. In addition contact was made with the Stability, Control, Simulation and Flying Qualities Technology Group of the McDonnell Douglas Corporation, Long Beach, who were conducting a TIFS investigation during the visit.