Worst case gust shapes for atmospheric turbulence with known spectrum

A worst case gust shape has been derived for turbulence or gust patches, assuming only that the average spectrum of such patches is known. The maximum value of the response can be calculated quite easily. The result differs from the PSD-method. Some examples of worst case inputs and outputs are given, also for nonlinear systems.

The deterministic power-spectral-density-method for linear systems

The Deterministic Power-Spectral-Density-method has been derived directly from the continuous P.S.D.-method. It can be regarded as a "translation" from the frequency domain to the space or time domain. The critical gust profile, giving maximum response, is obtained directly. The D.P.S.D.-method gives the same results as the continuous P.S.D.-...

Definition of P.S.D.-design loads for nonlinear aircraft

The Power Spectral Density (P.S.D.)-method is used to define design loads due to atmospheric turbulence. The design loads are calculated using linear transfer functions. These methods can not be used if the equations describing the behaviour of the aircraft are nonlinear. One method to define design loads for a nonlinear aircraft is by means of...

Predesign for flow visualizer. Project: Flow Graphics, Work package: Visualizer for 3D flow-calculation results

The results of calculations of two- and three-dimensional flows on blocked grid domains consist of vast data collections with a simple, regular structure. The inspection of these results can only be done efficiently by graphical means, and by exploiting the regular structure of the data. There is a large similarity between the format of the...

Standardized environmental fatigue sequence for the evaluation of composite components in combat aircraft (ENSTAFF = ENvironmental FalSTAFF)

Fatigue life assessment of composite structures in fighter aircraft necessitates testing with both mechanical and environmental loading at both coupon and structural element size levels. Testing facilities to run such tests are now available but environmental fatigue testing is expensive and time consuming. An environmental fatigue loading...

How to generate equal probability design load conditions

This report gives an outline of the method to generate equal probility design load conditions. The various steps are described.

Failures in advanced flight control systems of future transport aircraft

Future transport aircraft will be different from to-day's in that they will be designed to be statically neutrally stable or even unstable to improve economics, while the stability will be provided by means of a fly-by-wire flight control system. Since this system will be flight critical it is necessary to develop a philosophy on the treatment...

An introductory course on aircraft loading

The present course book has been prepared as lecture notes for a summer course given at the Technical University of Bandung (ITB) in the summer of 1984. This course took place within the framework of the TTA-79 Technical Assistance Project as agreed between the Governments of Indonesia and the Netherlands. The subjects of the course are listed...

Image quality criteria with emphasis on criteria for remote sensing imagery

Image quality plays an important role on the various levels of image processing. However, until now it lacks a survey of methods for the evaluation of image quality. With a grant of the Netherlands Agency for Aerospace Programs (NIVR) a study was performed with respect to the quantification of image quality. Some results of this study are...

Review and comparison of discrete and continuous gust methods for the determination of airplane design loads

Historical reviews of the discrete gust and the continious gust concept, in relation to the present requirements, are given in this report. A comparison is made between the discrete gust method and the power spectral density method on the basis of simple airplane models. No direct relation between the two methods exists. The main cause of the...

Operating conditions and materials selection and development in gas turbines

This paper consists of two parts. In the first part, concerning operational conditions in gas turbines, the following topics are covered: - the magnitude of temperatures, temperature profiles, and stresses in various components - transient temperature conditions, occuring as a result of e.g. throttle setting changes and affecting thermal fatigue...

Determination of low-speed longitudinal manoeuvring criteria for transport aircraft with advanced flight control systems

The application of Active Control Technology concepts and in particular the Relaxed Static Stability principle in certain categories of future transport aircraft will lead to the introduction of primary flight control systems incorporating full-time stability augmentation. For this category of transport aircraft adequate handling quality...

Stability of double gimballed momentum wheels

Due to the finite stiffness of rotor- and gimbal-suspensions, a double gimballed momentum wheel will oscillate with high natural frequencies. The stability of these oscillations is studied, in order to obtain requirements for the stiffness of the suspensions and/or the gimbal inertia properties. From energy considerations, it is concluded that...

An evaluation of the mission analysis concept for the definition of gust design loads

The mission analysis concept for defining design loads is assessed and compared with the current design procedure based on Design Envelope Concepts. Although the Mission Analysis Concept permits design loads of equal probability of exceedance to be obtained for all components, this does not imply that a fixed failure probability for the aircraft...