The forces on the vertical stabilizer play a primary role in the yawing moment equilibrium equation but also appear as small participants in some of the others. Figure 8.18 shows the geometric relationships that are used in evaluating these forces.
Horizontal Stabilizer—Example Helicopter
Єр = aF + iH at intersections
Fuse. Angle of Attack, deg.
FIGURE 8.16 Wind Tunnel Results Used to Calculate Fuselage – Induced Downwash Ratio at Horizontal Stabilizer
The equations for the forces on the vertical stabilizer are:
Xv = – Dv cos[p + iMv + r|T|/ + – Lv sin[|3 + iMy + Лі> + Ляк]
Yy = Ly costf + rMy + rTv + тц,] – D„sm[p + + Лтк + Лtr]
Zv = Xv sin[© – (e% + EFy + y,)]
where (3 is the sideslip angle and T| is the sidewash angle at the vertical stabilizer induced by the other components of the helicopter.
The basic equations for lift and drag of the vertical stabilizer are:
Ly = J^}AyC
Each of the new terms in these equations will be discussed separately.