during 1st harmonic by 46.28%, 2nd harmonic by 6.54% and 3rd
harmonic by 16.02%. Vibration accelerations during 4th harmonic
are higher on the seat with an absorber.
Fig. 13 shows graphs of vibration accelerations in the direction
of Y axis as function of PRF, during flight modes, on the seat in both
tests.
Analysis of effectiveness of damping vibrations in the seat, with
an absorber, in the direction of Y axis, given in Table 12 shows the
following:
- While the engine operates on RLP, vibration accelerations are
greater on the seat with an absorber relative to the seat without
an absorber during 1st, 2nd, 3rd and 4th harmonic. Rubber
absorber in this mode of flight practically performs as a multiplier
of vibrations.
- Throughout climb, vibrations on the seat with a built-in absorber
are damped more efficiently than on the seat without an
absorber: during 2nd harmonic by 51.24%, and 4th harmonic
by 15.91%. Vibrations during 1st and 3rd harmonic are smaller
on the seat without an absorber.
- Throughout horizontal flight, vibration damping on the seat
with an absorber is less than the damping on the seat without
an absorber at all analysed harmonics.