John Pattinson, Thomas Wilson, Martin Herring
DOI number: N/A
Conference number: IFASD-2015-052
Folding wing tips are about to become a reality on a civil airliner. They allow an increase in span without affecting the aircraft’s ability to fit into standard airport gates. This increased span will lead to an induced drag reduction, but at the cost of increased weight due to the fold mechanism, actuation and most significantly the need to strengthen the wing box for increased loads due to the extra span. In current designs, the folding tip will be unfolded on the ground and fixed in place before the aircraft takes off. This paper explores the concept of using this folding wing tip as a load alleviation device in flight in a similar way to the load alleviation function currently performed by spoilers and ailerons. Investigations at the University of Bristol using low fidelity simulations have demonstrated the potential of the in-flight folding wing tip device to reduce outer wing loads and thus wing root bending moments for both manoeuvre and gust cases. It is now important to understand the mechanism of the loads relief in more detail in particular the aerodynamics to understand local effects, i.e. local stall in the region of the fold and transonic effects.