Design and development of joined-wing aircraft
Teo, Te Wei
Date of Issue2015
School of Mechanical and Aerospace Engineering
DLR German Aerospace Center
The commercial aviation industry can be said to have reached its peak with the design of A380 by airbus, with its wingspan reaching the maximum allowable limit for airports. To further improve capabilities of aircraft, either airport limits have to change or more efficient aerofoils or technologies have to be developed. However, a solution lies within a whole new configuration by itself: the joined-wing aircraft. First conceptualised in 1906, it is said to have better aerodynamic and structural performance than the conventional wing-tail configuration. The joined-wing configuration is much lighter compared to its aerodynamically equivalent single wing counterparts. It also result in smaller wetted area, decreasing the drag. The combined weight savings and better aerodynamic performance will prove to be crucial for the commercial aviation industry. This report serves as a continuation on the study of the joined wing configuration, both the Wolkovitch aircraft and Prandtl plane. Designs were made in the preceding project of both configuration with varying parameters. The scope of this project will be to investigate said designs to determine the optimal configuration in terms of aerodynamic performance. Testing was done using both CFD simulations, and wind tunnel testing on actual models, focusing on the lift and drag coefficients. Due to time constraints, only one model was tested. Drag results were inconclusive, as the force balance was not sensitive enough to capture low drag forces experienced by the model during testing. Although it was noted that there was no additional increase in drag at stall angles contrary to flow separation theory. However, initial results were promising in terms of the lift coefficient. The value of lift coefficient is generally greater than most 2D aerofoils at the tested Reynolds number. Future work would to be needed to continue the tests with other models and compare the results to determine the optimum configuration.
Final Year Project (FYP)
Nanyang Technological University