Landing Gear Integration into Aircraft Structure in Early Design Stage

The demanded development towards various emission reduction goals set up by several institutions forces the aerospace industry to think about new technologies and alternative aircraft configurations. With these alternative aircraft concepts, the landing gear layout is also affected. Turbofan engines with very high bypass ratios could increase the diameter of the nacelles extensively. In this case, mounting the engines above the wing could be a possible arrangement to avoid an exceedingly long landing gear. Thus, the landing gear could be shortened and eventually mounted at the fuselage instead of the wings. Other technologies such as high aspect ratio wings have an influence on the landing gear integration as well. To assess the difference, especially in weight, between the conventional landing gear configuration and alternative layouts a method is developed based on preliminary structural designs of the different aircraft components, namely landing gear, wing and fuselage. Simplified parametric finite element structural models for the different components are introduced. These models are used to investigate different aircraft configurations with special regard on the landing gear integration. The structural models of the fuselage and the wing are sized according to defined load cases. After this first sizing step, the structural model of the landing gear is integrated and different landing gear load cases are applied. The developed methods aim to assess the impact of the different landing gear configurations, not only regarding the landing gear structure but also the surrounding support structure of the airframe. Results of the applied methods for aircraft configurations with different landing gear integration are presented and discussed.