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

variation of this rise time with T and E was presented in figure 4.
It can be seen fmm figure 4 that a given value of rise time can be
obtained at various combinations of T and E. The relation presented
graphically in figure 4 may be exptessed approximately by the following
equation :
Equation (26) combined with equation (21) yields a general relation for
the variation of piston area with inertia index. This relation is:
Equation (26) combined with equation (22) yields a general relation for
the variation of the product of the feedback ratio and the port width
with inertia index as follows:
2 3
The terms (i + $1 and BG +
in the above equations are proportional
to Ap and FW, respectively. Thus the numerical values of these terms
plotted as a function of E will indicate the variation of the size of
the servomotor with inertia index. The resulting plot is showq in figure
9. Ae a further aid in the choice of a value of E the maximum
cylinder pressure which is a function of E is also shown.
Figure 9 indicates .that values of E above 6 do not materially
reduce the size oaf the servomotor and result in large values of msximum
cylinder pressure. Values of E below 1 result in large servomotors and
in general would be used only if it is desirable to make the response
substantially first order. In this respect the above curves indicate
that it would be very difficult to reduce E to values close to zero
because the motor size and thus the mass of its parts become large, which
will tend to increase E. Values of E in the range from 2 .to 4 should
result in a servomotor that is very eatiefactoryboth from a size standpoint
@ , from a response standpoint.