Comparison of Predicted and Measured Formation Flight Interference Effects

Abstract

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Analytic Approach to Optimal Routing for Commercial Formation Flight

“…However, this would be a significant piece of work in its own right and is beyond the scope of this paper. For the purposes of this paper, average formation fuel-burn factors per fleet member are estimated using results from [21][22][23][24] for varying fleet sizes as follows: size of fleet n 1 is one, n 2 is 0.9; n 3 is 0.85; n 4 is 0.82; n 5 is 0.8; n 6 is 0.785; n 7 is 0.775. For example, if the front aircraft receives no savings, whereas the follower saves 20%, the resulting average is taken to be 1 0.8∕2 0.9 λ f;n relative to both aircraft in solo flight.…”

“…Section VI considers the impact on timing and introduces scheduling constraints. Studies based on individual pairings, looking only at the routing problem, have shown potential positive tradeoffs between the diversion to join formation and the reduction in drag formation flight produces [19][20][21][22][23][24]. Formation routes for five aircraft studied by Bower et al [4] focus on aerodynamic aspects such as wing tip separation.…”

Ride comfort in commercial aircraft during formation flight using conventional flight control

“…Wind tunnel tests for formation flight have shown that a substantial decrease in drag can be obtained in formation flight depending on the configuration. Blake and Gingras [24] measured a reduction of up to 25% in close formation flight. According to a study of extended formation flight by Ning [1] [26], for streamwise spacings of around 10 to 40 spans with low to moderately low atmospheric turbulence, a two-aircraft formation is capable of achieving a maximum drag reduction of approximately 30%, while a three-aircraft formation showed maximum reductions of around 40%.…”

“…Since its recognition, various studies have been undertaken to investigate the effects and advantages of formation flight. Some literature studies have focused on close formation flight, illustrated in Figure 2.3, where aircraft are separated by merely a few wingspans [22][23] [24] [25]. Showing good aerodynamic and control benefits, close formation flight minimises the induced drag of an aircraft and should greatly improve fuel efficiency in commercial aviation.…”

“…24. The plant is the FPA controller with the DQ law and the longitudinal dynamics of the aircraft in state space form, represented by Equation (5.41), Over a short time interval, the controller will be operating in a non-linear region, where the control signal will have no effect on the system output, namely the airspeed.…”