Methodologies for the determination of aircraft stability of the standard dynamics model at extreme angles of attack

Abstract The Standard Dynamics Model is a generic aircraft configuration created for the purpose of comparing wind tunnel dynamic stability findings. The model was tested statically in a low-speed wind tunnel at a Reynolds number of 94,000 over a range of angles of attack from $$0^\circ \le \alpha \le 90^\circ$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mn>0</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> <mml:mo>≤</mml:mo> <mml:mi>α</mml:mi> <mml:mo>≤</mml:mo> <mml:msup> <mml:mn>90</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> </mml:mrow> </mml:math> and a combination of roll and yaw angles. Computational Fluid Dynamic studies were completed over a series of Reynolds numbers for the scaled wind tunnel model, as well as for a full-scale free-flight aircraft. These results demonstrated the impact of the asymmetric vortex shedding phenomenon at high angles of attack in the form of peak side force and yawing moments appearing in the region of $$40^\circ \le \alpha \le 65^\circ$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mn>40</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> <mml:mo>≤</mml:mo> <mml:mi>α</mml:mi> <mml:mo>≤</mml:mo> <mml:msup> <mml:mn>65</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> </mml:mrow> </mml:math> . An initial static and dynamic stability assessment was also completed to assess the aircraft stability derivatives. These studies also suggest that, for the SDM aircraft, many of the coefficients and derivatives, examined within this paper, may appear insensitive to Reynolds number ( $$10^{3} \le {\text{Re}} \le 10^{7}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>3</mml:mn> </mml:msup> <mml:mo>≤</mml:mo> <mml:mtext>Re</mml:mtext> <mml:mo>≤</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>7</mml:mn> </mml:msup> </mml:mrow> </mml:math> ), especially below $${\text{Re}} = 3 \times 10^{6}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mtext>Re</mml:mtext> <mml:mo>=</mml:mo> <mml:mn>3</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> </mml:mrow> </mml:math> .