Unsteady Aerodynamic Characteristics of Airfoil with Moving Spoilers

Calculation and Identification of the Aerodynamic Parameters for Small-Scaled Fixed-Wing UAVs

“… , known as the slope of lift curve, fuses the separate cantilever-wing slope , the separate body slope , the separate horizontal tail slope and all the mutual effect between each of them. In details, , could be computed with the same diagram in [ 13 , 14 ], both of which are the function of the structural parameters of the wing and the Mach number . While the lift slope of body could be divided into the conical or ogive head, the cylindrical body and the shrinking tail part.…”

“…Lift of the wing-body part is the sum of the lift of separate body and the lift caused by the existence of the cantilever-wing , while the latter contains the lift of separate cantilever-wing , the interference lift from the body to the cantilever-wing and the opposite lift . Interference factors [ 13 , 14 ], , , are introduced to describe the mutual effect numerically, both of which concerns with the shape of the wing and the diameter-to-span ratio . Generally, when we have the condition that the aspect ratio is large enough ( ) and is small enough ( ), neglecting the mutual effect hardly matters.…”

“…The block factor ( ) should be multiplied to the dynamic pressure while the down wash angle should be eliminated to obtain the real angle-of-attack of the horizontal tail . The down wash angle after the wing-body part are nearly linear to the and the incidence angle of the wing, so the related derivatives are calculated in ( 3 ) and ( 4 ), in which , the down wash caused by the separate wing could be calculated in [ 13 , 14 ]. Thus, the lift coefficients could be deduced in Formulas ( 5 )–( 7 ), among which and are the interference factor between the body and the horizontal tail.…”

“… mainly contains the friction part and the due-to-lift part in the parasitic drag is neglected. So is calculated with the surface friction coefficient and correction factor [ 13 , 14 ]. , consistent with the formation , is calculated considering the wing-body part according to [ 13 , 14 ], in which of wing are closely related to the wing’s shape and of body is proportional to .…”

“…For instance, the diagram for calculate the lift curve slope of wing is fitted with the flight data according to the theoretical relationship with the geometrical shape of the wing and the Mach number. Monographs [ 9 , 10 , 11 , 12 , 13 , 14 ] introduce the basic aerodynamic theory of different aircrafts flying under different circumstances, and describe the detailed procedure of calculating all the aerodynamic derivatives. Specifically, the aerodynamic analysis of small-scaled aircrafts is often simplified for quite small Mach number, plain aerodynamic structure and small angle-of-attack assumption.…”