The purpose of this work is to investigate the effect of adding winglets of various dihedral angles to a small unmanned aerial system. Although significant research has been completed on the effects of winglets on large aircraft, there has been little focus on winglet effects for small unmanned systems. This work attempts to better understand the effects of winglets on small unmanned systems with modeling, analysis, and flight tests. The results of this research are promising and may help increase the capabilities of current and future unmanned aerial systems. The Advanced Aircraft Analysis modeling software is used to create a physics based models of the 40% scale YAK-54 unmanned aerial system. Five models are created to analyze the aircraft with no winglets, a wing extension, and winglets at angles of thirty, fourty-five, and sixty degrees. Aircraft stability and control derivatives for each model are developed to analyze the effects of winglets on the small aircraft's dynamic modes. Winglets are found to increase the damping ratio and natural frequency of Short Period mode. The lateral-directional stability of the small aircraft with winglets is also increased. For validation and verification purposes, winglets are manufactured at a dihedral angle of fourty-five degrees and attached to the 40% scale YAK-54 aircraft. Flight system identification tests are performed to verify the physics based models. Nomenclature AAA = Advanced Aircraft Aerodynamics AR = Aspect Ratio b = Span (ft) c = Chord C = Coefficient of L,M,N = Rolling, Pitch, and Yaw Moments (lbf•ft) L/D = Lift to Drag Ratio p,q,r = Roll, Pitch, and Yaw Rates (ft/s) S = Area (ft 2 ) SM = Static Margin T2S = Time to Double Amplitude α = Angle of attack (deg) β = Sideslip Angle (deg) δ = Deflection (deg) ε = Downwash Angle (deg) ζ = Damping Ratio λ = Taper ratio τ = Time Constant (s) ωd = Damping Frequency (Hz) ωn = Natural Frequency (Hz)