Ride Quality Within Conventional and Delta-Wing Trail Aircraft in Formation Flight

This paper investigates the ride quality for persons located within a trail aircraft flying in formation behind a lead aircraft to obtain fuel savings. As the trail aircraft flies at the optimum location with the largest fuel-saving benefits of formation, also termed the "sweet spot," it is subjected to a nonuniform induced wind field generated by the wingtip vortices of the lead. It is important to study the effect of this nonuniform wind field on the levels of comfort for passengers and crew located within the trail as it flies within and outside the aerodynamic influence of the lead aircraft. In this paper, aircraft formation pairs subjected to varying atmospheric conditions are modeled and simulated using different trail aircraft types. The ride quality/comfort levels are computed for persons at various locations within the trail aircraft in accordance with International Organization for Standardization Standard ISO 2631-1 ("Mechanical Vibration and Shock-Evaluation of Human Exposure to Whole-Body Vibration-Part 1: General Requirements," Geneva, 1997). It is demonstrated that, if a trail aircraft flies at the sweet spot and is subjected to the nonuniform induced wind field and/or atmospheric turbulence, the comfort levels are comparable to flight outside the aerodynamic influence of the lead aircraft with no additional detrimental impact, in terms of ride quality, to persons on board the trail aircraft.