Report of the Second Piloted Aircraft Flight Control System - Acgsc.org

conrtsnt speed). While this ryrtem worked and the pilots experienad
no difficulty in flying it, they were unanimous in condamming
it. Unfortunately no one flew it who had had no ezperience in aa
airplan.. TUr might have shorn 'nor natural a method of control it
in.
The control position feedback was unnaturally related to the force
feedbe. The wheel--rigidly connected to the ailerons-followed thin
emteblimhbg a bank. Ar every pilot knows, the no& requeme of
wento is romething like this:
1. The whed is rotated into the turn.
2. It is held in a deflected position.
3 Then it 'in returned toward neutral.
4. Finally it is slightly rotated oat of the turn
and held there to counteraat the overbanking
tendell~y.
With this first 8yst.m the automatic pilot did all tnir while 'tlu
pilot maintained a conrtant aileron force. It's almort iapoeeible to
beliwe, but neverthderr tme: not only way control smooth and stray,
bat nobow objected to this peculiar porition feedback. The objectionr
ware aoncerned with the magnitude of tbe forcer required to maintain
tb. aircraft in a steady tm. There objectiona, might have been wercome
by using wa.hout or nonlinear gradientr or both. Brief eqsrimanta
ware conducted with a strong centering characteristic and a
low rtiuk force gradlent for mod'arate diaplacementr. Thir artearr
like a carn reanr of control, with or without nonlinear gradientr,
howww, did not meet with agproval and was qulckly abandoned.
The next configuration which was tried war designed as a first
step toward making the aircraft control characteristics correspond to
those of a conventional aircrait. Specifically, the roll control
channel war alt sred in such a way that whenemor an aileron f orce
grater than three pounds war applied, the vertical gyro roll signal
and vertioal gpro roll erection were removed, and, by means of a
ratchet relay, raalned dilrconnected until a button on the control
wheel war deprersed.
The mdder channel was modified as followr: the directional gyro
rignal was completely removed and a lateral accelerometer was rubstituted
ar a yau reference device. !Chis configuration reeulted in a
control characteristic in which wheel force in roll commaaded an aileron
displacement (and therefore rate of roll at a given airepeed)