Advanced assembly solutions for the RACER joined-wing configuration 2019-01-1884
The demonstrator project RACER is developed under the leadership of Airbus Helicopters Group within a large European partnership and concerns the development of new VTOL formula in order to fill the mobility gap between conventional helicopters and airplanes. Thus, RACER is a compound rotorcraft including wings and propellers. The new wing arrangement suggested by Airbus Helicopters Groups is defined as a staggered bi-plane configuration with an upper and a lower straight wing at each side of the helicopter, both being interconnected at their outermost tips, forming a triangular framework. Responsible for the design, manufacturing and assembly of the wings is ASTRAL consortium consisted of GE Aviation and University of Nottingham.
The identification of the best strategy to assemble the joined wing configuration is quite challenging. In order to ensure that the final wing assembly will fit to the fuselage, a jig that simulates the fuselage was suggested by Airbus Helicopters Group. The main question raised during the assembly design and thus the objective of this work concerns whether the jig should be a one-piece structure or a modular one.
To justify one or the other option, a framework to quickly evaluate the best approach based on quantitative results is introduced. More specifically, the assembly key characteristics (AKC) of the RACER wing are initially specified. The developed assembly sequence and the datum plan are used in combination with the design tolerances of the interchangeability drawings to perform variation propagation analysis. The complexity of the specific wing, a 3D complex geometry, makes 1D tolerance stack up studies inaccurate. 3D assembly models were built based on homogeneous transforms, information that can be extracted directly from the CAD model. The extreme values of the AKCs are identified by formulating the problem as an optimisation one. Results indicated that the one-piece tooling is more beneficial.
David Bainbridge, Konstantinos Bacharoudis, Andrea Cini, Alison Turner, Atanas Popov, Svetan Ratchev