November 7, 2011 - Bombardier Aerospace confirmed that final results of a three-phase wind tunnel test program provided further validation of the CSeries aircraft’s aerodynamic design. They also support design predictions that the CSeries aircraft, optimized specifically for the growing 100- to 149-seat market, will deliver a step-change in fuel efficiency.  

The wind tunnel tests also contributed to the achievement of optimal integration of Pratt & Whitney’s ultra high-bypass ratio (12:1) PurePower® PW1500G engine. Initiated more than five years ago, during the early stages of the CSeries aircraft’s conceptual design, the wind tunnel test program progressed through the aircraft’s subsequent definition and detailed design phases. 

Validation of the CSeries aircraft’s aerodynamic design included extensive use of state-of-the-art Computational Fluid Dynamics (CFD), made possible through the use of contemporary super-computers that are significantly more capable and 100,000 times faster than computers available when the aircraft currently serving the 100- to 149-seat market were designed. These tools permitted the minimization of interference drag and also facilitated the design of the engine nacelle and thrust reverser. 

To simulate actual flying conditions, the wind tunnel tests were conducted with over 20 sophisticated scale models over more than 4,500 testing hours at facilities in Canada, France, Germany, the Netherlands, the United Kingdom and the United States. “Simulated conditions during the wind tunnel tests closely correlate to real world flying conditions and the resulting data were used to improve and validate final CSeries aircraft design and systems,” said David Tidd, Vice President, CSeries Integrated Product Development, Bombardier Commercial Aircraft.

“This latest achievement for the CSeries aircraft represents the most extensive and complex wind tunnel testing that Bombardier has ever conducted; it marks another key advance in the jetliner’s development.” The scale models of the CSeries jetliner used in the testing were equipped with precise instrumentation to measure air flow, including as many as 700 pressure-sensitive ports over the wings, fuselage and tail.

The models included moving parts, such as wing flaps and leading edge slats, which could be repositioned to reflect actual flying events. Some models were equipped with miniature air-driven turbine engines to gauge the air flow interference with the aircraft wings. The largest of the models, at 13.7 per cent scale, had a wingspan of approximately 4.5 metres (15 feet). Using the scale models and the environmental conditions possible in the wind tunnels, Bombardier engineers were able to simulate the aerodynamics of the CSeries aircraft in various flight scenarios such as landing, take-off and cruising at high altitudes.