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POWER spectral methods for computing loads on aircraft due to atmospheric turbulence have been developed over the past dozen years or so. Such calculations are carried out on all new aircraft, and to date the results have been used to amplify fatigue and environmental data. The United States Federal Aviation Agency (FAA) is proposing the introduction of power spectral gust design procedures for and computing design limit loads on commercial aircraft. A parallel programme for the development of taxi load criteria is also being considered. The FAA have sponsored/research on the development of such power spectral gust methods and currently two approaches are being examined by industry. These are a design envelope approach and a mission analysis approach. A similar British investigation is now under way to establish the validity of the American proposals.

The purpose of this paper is to identifying ways to reduce the effects of wing-vortex interaction by applying surface porosity on selected areas of the exposed surface. A number of papers recently have investigated the aerodynamic implication of free-stream vortices impinging upon airfoils.

The free-stream disturbance in these studies were represented by planting a vortex ahead of the wing or using some other disturbance invoking mechanism like von-Karman vortices in the wake of a cylinder or using a flipping plate to invoke a discrete vortex. In the present work, a well-defined method was used to germinate a system of controlled vortices of known strength, size and frequency ahead of the wing, and the impact of the subsequent interaction was studied with and without the presence of the surface porosity. The simulations tackled a number of cases when porosities of up to 20 and 22 per cent were applied to selected regions near the leading edge, with vortices of controlled strengths directed at the wing surface.

The results showed that the effects of large vortices spanning the entire lengths of the wing can indeed be damped when porosity is selectively applied at strategic regions.

Surface porosity application at strategic regions of a wing may dampen the effects of the unsteadiness of the incoming flow. This has profound implications on flight safety and structural damage prevention. Further implications could possibly be extended to UAV and wind turbines that operate at heavy gusting environment.

Implementation of this particular method resolves some of the issues arisen when an airplane encounters atmospheric turbulence.

This paper seeks to present a feedback error learning neuro‐controller for an unstable research helicopter.

Three neural‐aided flight controllers are designed to satisfy the ADS‐33 handling qualities specifications in pitch, roll and yaw axes. The proposed controller scheme is based on feedback error learning strategy in which the outer loop neural controller enhances the inner loop conventional controller by compensating for unknown non‐linearity and parameter uncertainties. The basic building block of the neuro‐controller is a nonlinear auto regressive exogenous (NARX) input neural network. For each neural controller, the parameter update rule is derived using Lyapunov‐like synthesis. An offline finite time training is used to provide asymptotic stability and on‐line learning strategy is employed to handle parameter uncertainty and nonlinearity.

The theoretical results are validated using simulation studies based on a nonlinear six degree‐of‐freedom helicopter undergoing an agile maneuver. The neural controller performs well in disturbance rejection is the presence of gust and sensor noise.

The neuro‐control approach presented in this paper is well suited to unmanned and small‐scale helicopters.

The study shows that the neuro‐controller meets the requirements of ADS‐33 handling qualities specifications of a helicopter.

THE Air Ministry has lately introduced extensive revisions into the official requirements for the strength of civil aeroplanes and the object of this article is to consider briefly their significance and effect on the trend of design. The general nature of the problem and the development and character of the system which is being modified must, however, first be summarised if the real meaning of these changes is to be appreciated. The problem of fixing the requisite strength for a given aeroplane divides naturally into two parts; first the magnitude of external loads which the aeroplane must be assumed to encounter, second the structural problem of determining the methods to be used in ascertaining the resistance to those actions.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Notes of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

The purpose of this paper is to present the application of the neural-based estimation method, Neural-Gauss-Newton (NGN), using the real flight data of a small unmanned aerial vehicle (UAV).

The UAVs in general are lighter in weight and their flight is usually influenced by the atmospheric winds because of their relatively lower cruise speeds. During the presence of the atmospheric winds, the aerodynamic forces and moments get modified significantly and the accurate mathematical modelling of the same is highly challenging. This modelling inaccuracy during parameter estimation is routinely treated as the process noise. Furthermore, because of the limited dimensions of the small UAVs, the measurements are usually influenced by the disturbances caused by other subsystems. To handle these measurement and process noises, the estimation methods based on neural networks have been found reliable in the manned aircrafts.

Six sets of compatible longitudinal flight data of the designed UAV have been chosen to estimate the parameters using the NGN method. The consistency in the estimates is verified from the obtained mean and the standard deviation and the same has been validated by the proof-of-match exercise. It is evident from the results that the NGN method was able to perform on a par with the conventional maximum likelihood method.

This is a partial outcome of the research carried out in estimating parameters from the UAVs.

The purpose of this paper is to report the research activity of Politecnico di Torino concerning the MicroHawk platform (micro‐aerial vehicles – MAVs) and to present the design and the development of a basic flight simulator for educational/training purpose.

A simulator is an easy‐to‐use system for the analysis of maneuver response, the dynamic study and the evaluation of the aircraft flying and handling qualities for different aircraft categories. The software implementation, including the definition of mathematical model, the visual scenario and the real‐time data analysis graphic interface, are delineated in this paper. In addition to this experimental phase, an important effort is done to incorporate simulation into the autopilot tuning process.

An intense flight activity is carried out to test the flight control system performances of the MicroHawk platform and to establish general procedures to ensure the correct operation of all subsystems. The automatic flight of MAVs has been studied with success for territorial surveillance and map project.

In order to simplify the use of these platforms by the end‐user, a software interface will be designed to calculate automatically the flight plan, ensuring the desired trajectory design and collision avoidance.

The autopilot simulation integrated with vehicle's dynamics can be used to reduce the platform set‐up time and the risk of losing the prototype. The simulator training permits to study flight complex plane, in order to obtain better platform performances in real conditions. Starting from a simple scenario, it is possible to set up and upgrade the mission at any time during the simulation.

THE Eleventh Annual Aircraft Engineering Research Conference of the American National Advisory Committee for Aeronautics, held at the Langley Field laboratories of the Committee, was as usual attended by a large and representative group of manufacturers, engineers, government officials and university instructors. These conferences are particularly valuable because they give to the industry a review of research conducted by the Committee during the year, and to the Committee suggestions for further investigations from the constructors. It is hardly necessary to emphasize the benefit derived from such an exchange.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics and publications of other similar research bodies as issued

The causes of “ altitude sickness ” are enumerated and discussed, and a definition is given of the limits within which pure oxygen or mixtures of air and oxygen may be breathed at various heights, with the symptoms and effects produced. The usefulness of the pressure‐cabin and the requirements which it must satisfy are also considered. Ear troubles occurring in flight, and the risk of embolism in rapid ascents, are discussed, together with their causes, and the possibility of eliminating these troubles is examined.