Within the framework of a major European co-operative research project on rotorcraft aerodynamics and acoustics (Helishape), a parametric model rotor test was conducted in the open test section of the DNW using DLR's MWM test rig, and a highly instrumented model of a fully articulated ECF rotor equipped with blades of advanced design with two exchangeable blade tips. One set of blade tips (7A) was rectangular, while the other (7AD1) was a swept-back parabolic-anhedral shape. The objectives of this experimental research were to evaluate noise reduction techniques (conceptionally by variation of rotor speed, dedicated tip shapes and advanced aerofoils, as well as operationally, by identifying low noise, BVI-minimising, descent procedures) and to validate the partners’ aerodynamic and aeroacoustic codes. A comprehensive set of simultaneous acoustic and aerodynamic blade surface pressure data and blade dynamic and performance data was measured. In addition, valuable information on the tip-vortex geometry and blade-vortex miss distance was obtained by LLS flow visualisation. The experimental equipment, the test procedures, and the test matrix are briefly described. A survey of the main results is presented and the trends of the most important parameter variations for both rotors are discussed.

This paper examines the feasibility of using neural networks to represent the effects of human operators in computer models of complex man-machine systems. In the suggested approach, data from man-in-the-loop simulators are used to train the networks. The method has been tested on several typical data sets using a stand-alone prototype system, consisting of a three-layer feed-forward network with a Chemotaxis training algorithm. Successful results have been obtained, and these can be used to place constraints on the quality, quantity and type of simulator data required in future applications.

The NH90 project formally started in September 1992 when France, Germany, Italy and The Netherlands agreed a contract with NH Industries on the design, development and qualification of an 8-9 tonne class helicopter which shall replace the present fleet of light transport and naval helicopters in the various military services of these states.

The NH90 comprises two versions that are based on a weapon system development specification for a Tactical Transport Helicopter (TTH) and a Nato Frigate Helicopter (NFH). The design of the NH90 follows the principle of having as many common basic systems and subsystems as possible in both versions, and to utilise a high level of avionics system integration to provide the capabilities to carry out the required tactical missions with a minimum of crew and crew workload.

Consequently, structure, dynamics, general vehicle, and flight control systems, core avionics, and mission equipment are principally common features for both weapon systems. The integration of two specific mission systems, on the other hand, provides the capabilities to employ both versions with a high rate of efficiency in their individual roles. The TTH tactical transport for air forces and armies, and the NFH as a ship embarked anti-submarine/anti-surface unit warfare (ASW/ASUW) for navies, both with the potential for a variety of other missions. The various subsystems of both mission systems, use modern equipment for acquisition of mission relevant information and data, their processing, transformation and display and provide automatic actions or advise to initiate adequate crew reactions.

A methodology for the analysis of the performance of different aircraft configurations in the conceptual design phase is addressed. A scalar objective function, takeoff weight, is minimised by means of a numerical optimisation technique which takes into account the high number of geometrical parameters and the flight mechanics requirements involved in the problem. The study is confined to the cruise segment of the mission, and results are shown both for tail-aft and canard configurations. The above technique produces “equally” optimised configurations, thus giving a meaningful means to compare tail-aft and canard configurations.

Screen separations as little as 0.02 chamber diameters do not adversely affect suppression of mean-flow non-uniformity provided the overall pressure drop coefficient, K, does not exceed about 3.5. At larger K a velocity overshoot develops near the wall boundary layers, which decreases only slowly with wider separation. A simple approximate extension can be made to the theory of Taylor and Batchelor for any number of closely-spaced screens. This shows good agreement with measurements and with low-drag screens predicts perfect attenuation when the overall pressure-drop coefficient is 3.2 or 7.6. Some inferences regarding the effect of close screens on turbulence suppression are also drawn.