FLYING QUALITIES OF PILOTED AIRCRAFT - CAFE Foundation

MIL–STD–1797AAPPENDIX Achanges sign as stall is approached), angle–of–attack limiting or inhibition may be necessary(WADC–TR–58–82) with pitch feedback:1T θ –X u Z u X wZ w1 –Z δ MM δ Z1 – Z δ MM δ Zuuww2gVTWV2(T/W)ucos(α+i ) – tC C1 1 – T W sin(α+i t ) – D C L 1C N C α L C δ m1 –αCmC δ Nα1 +Z TcC L δCmδ– sin(α+i ) tTWV2(T/W)uC2g D 01 C LV C C L L αC DC2Lthe latter approximation holding for CL>> C D , parabolic drag (where CD 0is the zero–lift drag) andneglecting thrust effects and CL . Note that in terms of the low–frequency path zero, from Aircraft Dynamicsand Automatic Control:1 1 g ZT u1 –(Z δ /M δ ) (M /Z u ) uh T 1 V1 Z w1 – (Z δ /M δ ) (M /Z w ) wso that generally 1/T θ1 approaches zero at some angle of attack above that for zero 1/Th 1 or dγ/dV. Thesetransfer–function numerator approximations apply only to cases of stabilization and control through the samemoment effector.5.2 Flying qualities requirements for the pitch axis—verification5.2.1 Pitch attitude dynamic response to pitch controller—verification5.2.1.1 Long–term pitch response—verification. Verification shall be by analysis, simulation and flighttest.VERIFICATION RATIONALE (5.2 through 5.2.1.1)Testing specifically for long–term flight characteristics is time–consuming. However, most long–termdeficiencies will surface during attempts to stabilize at a new flight condition, for example establishing asteady climb or turn, changing airspeed, or flaring for landing.169