Stabillity Derivative - Small Angle Approximation

[SpaceShawn]

In determining the Center of Pressure, the Stability Derivative is a function of the Angle of Attack.

By applying the Small Angle Approximation and assuming an angle of attack of less than 10 degrees, can the Stability Derivative (and thus the Center of Pressure) be considered constant during flight?

[neil1993]

For the high speed flight, yes. For the late flight, it doesn't matter. For the early flight where the rocket is accelerating and just coming off the rod, NO! A slower moving rocket will have a very large AoA if there are strong winds. This will usually shift the CP backwards and renders the small angle approximation incorrect.

[SpaceShawn]

The Barrowman method holds valid only under ranges of angle-of-attack that fall under the small angle approximation. Slightly more accurate values can be determined by taking the sin of the angle-of-attack, but not by much