6 research outputs found

    HYLTEC Laminar Flow Systems Flight Tests: Flight Testing of Anti-Icing and Anti-Contamination Systems on the DLR Do228 Test Vehicle

    No full text
    Hybrid laminar flow control (HLFC) promises a large potential for drag reduction. Much effort has been put into the development of this technology, but relatively little experience has been gained with the hardware and systems that will be required to protect the wing surface against ice accretion and insect contamination. In frame of the European program HYLTEC a new leading edge box has been developed for the wing of the DLR test aircraft Dornier Do 228. The box is equipped with a laser drilled suction surface in combination with different test panels for bleed air anti-icing, shield protection, fluidic anti-contamination, fluidic anti-icing and a reference area. Suction pressure is produced by a bleed air driven jet pump. The pressure distribution can be measured by one row of pressure taps. Transition location is observed by an infrared camera. A video camera near the wing tip records insect and ice accretion at the leading edge. The flight tests have been conducted in four test campaigns starting December 2001 and being completed in September 2002. First tests of the suction system showed that depending on flap deflection and suction velocity transition locations between 25% and 50% of chord length could be achieved. Without suction no laminar flow could be observed. In three test campaigns the different systems show their ability to keep the surface clean against insect contamination and ice accretion. The mechanical construction as well as the systems layout and the instrumentation is described in detail in [1] and [2]

    Aeroakustischer Entwurf eines 6-Blatt Propellers Teil des Projektes ''Leises Propellerflugzeug''

    No full text
    The objective of the present study is the new design of a 6-blade propeller for the LFU 205 aircraft of the German Aerospace Research Establishment (DLR). A preceding experimental study has indicated the potential of noise abatement by reducing the blade tip Mach number while maintaining a constant engine speed. Starting from the results of the experimental study and fundamental considerations with regard to noise reduction and aerodynamic quality, a new propeller is designed on the basis of a diameter reduction from 1.93 m to 1.5 m. Besides the design of a 6-blade and a 4-blade propeller, a propeller, measured in the German-Dutch Wind Tunnel (DNW) with a diameter of 2.03, is used both as a reference propeller and to verify the methods applied here. (orig.)Available from TIB Hannover: RO 8051(1995,21) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

    Stroemungssichtbarmachung an Hubschrauberrotorblaettern mittels Acenaphthen

    No full text
    With 22 figs., 2 tabs., 10 refs.Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

    Numerical investigation on two airfoil analysis codes using the Euler and Navier-Stokes equations in inviscid and viscous flows

    No full text
    Under the framework of the DLG-CAE cooperation topic: 92-16, numerical investigation is carried out on two transonic airfoil analysis/design codes at the Institute of Design Aerodynamics, DLR, Braunschweig. The first is the DLR Airfoil Design Method based on the solutions of the Euler/Navier-Stokes eqs., and the other is the ISES Transonic Airfoil Analysis/Design code of MIT, which uses the Euler eqs. with viscous correction. This report summarizes the analysis part of the investigation where a DLR-2D Euler/Navier-Stokes code, which is the analysis part of the DLR Airfoil Design Method, is compared with ISES, running in direct mode, through numerical computations on several airfoils in inviscid and viscous flow conditions. The investigation suggests that both DLR-2D Euler/Navier-Stokes and the ISES codes are very powerful tools for the analysis of airfoils under subcritical and supercritical flow conditions, even with laminar separation bubbles and turbulent separations. Detailed discussions are made on parametric study, drag estimation, total pressure losses, and the features of different numerical algorithms, meshes and turbulent models involved. Viscous analysis results are compared with experimental data available and the CPU time needed for each code is also compared. (orig.)This work is under the DLR-CAE cooperation topic: 92-16, (Report 1)Available from TIB Hannover: RN 4165(1995,5) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

    Numerical investigation on two airfoil design codes based on the solutions of the Euler and Navier-Stokes equations

    No full text
    Under the framework of the DLR-CAE cooperation topic: 92-16, numerical investigation is carried out on two transonic airfoil analysis/design codes at the Institute of Design Aerodynamics, DLR, Braunschweig. The first code is the DLR Airfoil Design Method based on the solutions of the Euler/Navier-Stokes eqs., and the other is the ISES Transonic Airfoil Analysis/Design code of MIT, which uses the Euler eqs. with viscous correction. This report summarizes the design part of the investigation where both methods are compared with each other through design studies of transonic airfoils in inviscid and viscous flows. The design examples include the redesign of existing airfoils, design under ill-posed conditions, design with arbitrarily prescribed target Cp distributions, modifying NLF airfoils by changing the slopes of the favourable pressure gradients and the design of new NLF airfoils. The investigation suggests that both DLR Airfoil Design Method and the ISES code could be considered as very powerful tools for the design of transonic airfoils. They have successfully brought the accuracy of the inverse problem ot the same standard of the direct problem, that is, the solution of the Euler or Euler/NS equations. Great improvement has been achieved with the modifications to the orginal Takanashi's approach made by the DLR Airfoil Design Method. (orig.)This work is under the DLR-CAE cooperation topic: 92-16, (Report 2)Available from TIB Hannover: RN 4165(1995,6) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

    Konzeptstudie zur Demonstration der nach dem heutigen Stand der Technik realisierbaren Laermminderung bei Propellerflugzeugen der Allgemeinen Luftfahrt

    No full text
    In order to reduce aircraft noise emissions at airfields, this paper investigates that potential of noise reduction which can be achieved for piston-engine propelled General Aviation aircraft in accordance with the state of the art by retrofitting them with low-noise propellers and engine auxiliary mufflers. For this purpose, using an airplane equipped with a common 147 kW driving engine as an example, a low-noise propeller and an auxiliary muffler are designed to reduce engine exhaust noise. As compared to a 2-bladed reference propeller, the propeller diameter is reduced for noise abatement. To maintain aerodynamic efficiency, one uses more blades with optimized airfoil sections and lift distribution. The new design does not exhibit any performance penalties in cruise flight. At lower airspeeds, however, thrust losses have to be accepted. Because of the reference of this study to the regulations of noise certification, noise levels and level reductions are indicated in the form of the A-weighted total noise level. As a result one expects an A-weighted propeller noise level which is by 12.4 dB lower as compared to the reference propeller. To exploit this reduction potential, the required reduction of the A-weighted engine exhaust noise was determined to be 9 dB by noise measurements on the engine test rig. Preliminary design calculations for optimal design of a resonance muffler show that a corresponding insertion loss will be reached without any significant performance losses. (orig./RHM)Available from TIB Hannover: RO 8051(95,17) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
    corecore