92The VAAC Harrier

The DERA vectored thrust aircraft advanced flight control (VAAC) Harrier is a research aircraft sponsored by MOD which is being used to research control concepts in handling and control. The goal is to demonstrate that through the application of new approaches and design methods, a major reduction in pilot workload can be assured. More background information can be found in Reference 5 , The aircraft is a modified two-seater training aircraft a safety pilot flies from the front cockpit and the...

133 Civil aircraft developments

The jet age for civil transport aircraft started after World War II with the De Havilland Comet 1 (first flight 27 July 1949) and the Boeing 707 (1954). The four-engined 707 carried 200 passengers. Despite this aircraft's weight (150 000 kg), the FCS only needed hydraulic boosters for the rudder and the spoilers. Elevators and ailerons were aerodynamically balanced internally to keep the force levels down 18 . The early spring-tab design for the rudder was changed in order to avoid the...

734 Eurofighter 2000 EF2000first flight 1994

EF2000 (Figure 7.11) basically takes the design concept of the experimental aircraft programme (originally developed with partners DASA, then MBB) forward into a series-production weapons system. The unstable aerodynamic configuration and full-authority digital FCS are common with EAP, but the wide range of stores to be carried constituted a major development in the analysis of the structural-coupling problem. The resulting wide variation of structural dynamics was ameliorated on the Tornado...

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The Laplace transform of eqn 2.73, assuming zero initial conditions, is and eqn 2.74 is the reduced-order lateral-directional characteristic equation retaining a very approximate description of the spiral-mode characteristics only. Whence, an approximate expression for the time constant of the spiral mode is defined The dutch-roll mode is a classical damped oscillation in yaw, about the oz axis of the aircraft, which couples into roll and, to a lesser extent, into sideslip. The motion described...

544 AFCS configurations

The system configuration for the AFCS installed on the GKN Westlands Merlin EH101 helicopter, supplied by Smiths Industries Aerospace, is shown in Figure 5.10. This system comprises five line-replaceable units, namely, a pilot's control unit, two flight control computers, a dynamic sensor unit used to increase the availability of attitude data and a hover-trim controller for the military variants of this helicopter. Figure 5.11 illustrates how the level of redundancy can be increased in an AFCS...

6525 Flight test and analysis technique development

During the flight-trials phase of the EAP demonstrator, a number of significant developments took place both in the provision of test facilities and in the use of real-time model-validation techniques. Of these, the provision of an in-flight structural-mode excitation system within the FCS and the use of a real-time air data system model validation analysis technique are of particular interest and are described below. Other developments included the provision of a synthetic target tracking...

Actuation systems

Typical Hydraulic Schematic Symbols

Actuation systems are a vital link in the flight control system, providing the motive force necessary to move flight control surfaces. Whether it is a primary flight control, such as an elevator, rudder, taileron, spoiler or foreplane, or a secondary flight control, such as a leading edge slat, trailing edge flap, air intake or airbrake, some means of moving the surface is necessary. Performance of the actuator can have a significant influence on overall aircraft performance and the...

181 The Airbus flybyxvire family

The first civil fly-by-wire aircraft was the Airbus A320 which made its first flight on 22 February 1987. Twelve years on, a family of Airbus fly-by-wire aircraft exists, featuring the A319, A320, A321, A330 and the four-engined A340. Such Industrial considerations for flight control 35 Rudder - Industrial considerations for flight control 35 Rudder - Figure 1.13 Airbus 330 control surfaces Figure 1.13 Airbus 330 control surfaces a family concept offers great advantages for the airlines it...

0 05 1 15 2 25 3 35 4 45

Figure 7.22 Limit-cycle condition for reduced-order aircraft model has been considered is the software rate limiter. Comparison of the predicted limit cycles with those obtained from time-domain simulation has shown that a simplification of the nonlinearities still produces a good estimate of the limit-cycle frequency and amplitude. Unfortunately, this procedure relies on the existence of reliable frequency-response data for all the linear elements of the system. In the case of the real...

53 System design considerations

Figure 5.4 illustrates the design considerations that flow from the overall consideration which is to achieve automatic flight control. The list of considerations may not be exhaustive and probably could be grouped or segregated under different headings. However, the reader can gain a basic understanding of how the considerations grow and become interdependent as the design is decomposed. The interdependency between levels is emphasised by the databus notation rather than connecting individual...