The influence of modelling asymmetric lateral track dispersion on aircraft noise level predictions

In the Netherlands, noise exposure forecasting is based on the assumption that lateral track dispersion, for both take-off and landing, can be represented by a symmetrical probability distribution. Radar track observations at Amsterdam Airport Schiphol (AAS) show that the actual track dispersion is certainly not symmetrical. As a result,...

Gem Cyclic Life Control: A Smarter Maintenance Item within the Royal Netherlands Navy

As part of a general Smarter Maintenance policy, the Royal Netherlands Navy has implemented the so-called Cyclic Life Control concept for the engines of its Westland Lynx helicopters. The aim is to have an autonomous, cost-effective and simple way to decrease costs on hard time maintenance. Cyclic Life Control allows the Royal Netherlands Navy...

WISPER and WISPERX: A summary paper describing their backgrounds, derivation and statistics

Two newly developed research tools for wind turbine blade fatigue evaluation, called WISPER and WISPERX, are presented. WISPER and WISPERX are standardized variable-amplitude test loading histories that are based on operational flap loading measurements on 9 different horizontal axis wind turbines. These turbines cover a wide range of materials,...

WISPER and WISPERX Final definition of two standardised fatigue loading sequences for wind turbine blades

WISPER and WISPERX are standardised variable-amplitude test loading histories for use in the fatigue design of horizontal axis wind turbine blades. They are based on flap load service measurements on 9 different horizontal axis wind turbines, covering a wide range of materials, rotor diameters and geographical locations. The present report is...

Gebruiksbewaking bij de marine luchtvaartdienst

The RNLN Fleet Air Arm (Marine Luchtvaartdienst) has recently implemented a series of usage monitoring procedures for optimisation of Orion and Lynx operation. Goal is an enhancement of efficiency, economy and safety of the usage of both aircraft systems. Compared to the benefits, the efforts for achieving useful usage monitoring are relatively...

Analysis of space shuttle accelerometer data

Within a ESA programme to optimize the damage tolerance approach to design of Space Shuttle payloads, actual flight data from four Space Shuttle missions have been analysed by NLR. The task was to derive typical mission event load spectra from loadtime accelerometer measurements. The quality of the analog Input data, available to NASA for pre...

WISPER : a standarized fatigue load sequence for HAWT-blades

WISPER is a variable-amplitude test loading sequence for use in the fatigue evaluation of horizontalaxis wind turbine blades. It has been derived from flap load measurements on 9 different European wind turbines, covering different materials, a wide range of rotor-diameters and various geographical locations. The rationale of developing WISPER ...

Cold Turbistan; final definition of a standarized fatigue test loading sequence for tactical aircraft cold section engine discs

European approaches in standard spectrum development

Typical characteristics of various types of service loading are presented as they were discussed during the establishment of standardised test load sequences. Counting methods are reviewed and a simple and powerful algorithm is given to perform rainflow counting and to store the counting results afterwards. Synthesis procedures are discussed...

Fatigue load measurements and evaluation of the 25 m hawt at Petten, the Netherlands

Load measurements on the 25 m. Horizontal Axis Wind Turbine (HAWT) have been carried out to establish fatigue load spectra for 7 load channels in 9 modes of operation, i.e. 7 wind speed classes and the start and stop at the cutout wind speed. Special attention has been paid to the location of the zero levels for the different recordings. The...

Development of a flexible and economic helicopter engine monitoring system

In terms of fatigue life consumption the Royal Netherlands Navy (RNLN) is by now one of the leading operators of the Westland Lynx helicopter. Consequently,, the RNLN feels a growing need to gain more insight into the Lynx fatigue loading environment. The topic of Lynx engine loading is subject of a RNLN funded NLR research programme aimed at...

TURBISTAN: A standard load sequence for aircraft engine discs

The development of TURBISTAN is a joint international effort to derive a loading standard representative for fighter aircraft engine disc usage. A representative loading standard offers considerable potential advantages over the present zero-max type of loading used for disc material evaluation. This is because the standard incorporates the...

Helix and Felix: Loading standards for use in the fatigue evaluation of helicopter rotor components

Two new standardised fatigue test load histories for helicopter rotors are presented. To further introduce the item of load-standardisation a brief description is given of already existing loading standards for fixed wing aircraft which are being used in many laboratories all over the world.

The effect of spectrum variations and changes in flight sequence on crack growth in 2024 T351 Alclad sheet of 2 mm and 8 mm thickness

This memorandum presents results of crack propagation tests on notched Alclad 2024-T351 sheet specimens. Two thicknesses were investigated (2 mm and 8 mm), as well as various spectrum modifications and the effect of clustering of severe flights within the test load sequence.

Fatigue tests on notched titanium specimens under the helicopter test load spectrum Felix

In international collaboration, two standardized fatigue test load sequences for helicopter components, HELIX and FELIX, have recently been established. The present report describes tests on notched Titanium Alloy specimens to evaluate the properties of the FELIX standard. Tests included Constauit Amplitude, block programme and FELIX-flight...