Stabilator Angle per g
The preceding developments will apply to the stabilator configuration if Д Se is replaced by Aihs, CMs by CM„ and CLs by CLi. A separate analysis of the stabilator with regard to a steady maneuver is therefore unnecessary.
Stick Force per g
Stabilizer-Elevator Configuration In order to calculate the stick force required per g of normal acceleration, we again use Equations 8.27 and 8.37.
Си — bOct + bi 8e + Ьз St
Vt ~q~s6 = bl[a(l ~ e“)- ‘a* + 21 q J + b2 8e + b3 8,
Now let 5, be adjusted to trim P to zero for unaccelerated flight. For this condition let a = a0 and Se = 8^, such that a = а0 + Да, 8e = 5^+ A<5e. It then follows that
Thus the stick force per g becomes
The position of h for which P equals zero is known as the stick-free maneuvering point and is denoted by h’m. In terms of h’m, the stick force per g becomes
Stabilator The stick force per g for the stabilator is obtained in a manner similar to that which was followed for the stabilizer-elevator configuration. The moment coefficient about the pivot line is once again given by Equation 8.32. Also, in the steady pull-up, Equation 8.63 again applies and 8 is related to ihs by Equation 8.33. Thus, for the stabilator,
г) GqSc = "" e“) ~ ihs + 21 <?] + b2(keihs + S0)
Now let S0 be adjusted so that P = 0 for q = 0. For this trim condition we again let а = a0 and ihs = ihso, so that, generally, а =а0+Да and ihs + ihSo + Дihs. Thus, ,
G^jsT, * – «■> ■- ЛІ. + * p(j)] + W. ii.
The similarity of this relationship to the corresponding equation for the stabilizer-elevator tail configuration is obvious. Again, we can express the stick force per g in terms of the stick-free maneuvering point.
An airplane loaded so that the center of gravity is close to the stick-free maneuvering point presents a dangerous situation. The pilot can impose extreme inertia loads on the airplane with the application of little or no control force. Such a situation, however, is rarely encountered if an adequate static margin is maintained, since the stick-fixed and stick-free maneuver points are aft of the corresponding neutral points.