tion. Engine operation on RLP has the largest impact on vibration
accelerations in Z axis. Magnitudes of vibration accelerations on
the seat, measured in 1st test, during 1st harmonic, in all flight
modes are given in Table 7.
During 1st harmonic, the lowest vibration acceleration values
were measured on the seat. Horizontal flight and climb have made
the largest contribution to the intensity of vibrations on the seat in
X axis. Engine operation on RLP contributed the most to the intensity
of vibrations on the seat in Y axis. In the direction of Z axis horizontal
flight has the greatest impact on the intensity of vibrations
at 1st harmonic. Magnitudes of vibration accelerations on the seat,
measured in 1st test, during 2nd harmonic are given in Table 8.
Table 9 shows vibration accelerations on the seat, measured in
1st test, during 3rd harmonic.
Engine operation on RLP has the largest contribution to vibration
accelerations on the seat, in 1st test, during 3rd harmonic, in
X axis. In the Y direction horizontal flight has the greatest impact.
Engine operating on RLP contributes the most to vibrations in the
direction of Z axis. Magnitudes of vibration accelerations on the
seat, in 1st test, during 4th harmonic are given in Table 10.
Engine operating on RLP has the largest contribution to vibration
accelerations on the seat, during 4th harmonic, in X and Z
axes. Climb has the dominant impact on vibration accelerations
in Y axis. Evaluation of effectiveness of vibration damping on the
seat in the directions of Y and Z axes, using a rubber absorber, is
made by comparing data of vibration during selected harmonics,
on the seat during flight regimes without the absorber, and with
the absorber built in under the seat supporting beam. Data of
vibration acceleration in the direction of Z axis, as function of
PRF, during both tests, on the seat, are presented in Fig. 12 and
Analysis of effectiveness of vibration damping on the seat with
an installed absorber, in the direction of Z axis, shows the
following:
- While the engine operates on RLP, vibrations on the seat with
an installed absorber are damped during 1st harmonic by
18.19% and during 2nd harmonic by 70.20%. Vibrations during
3rd and 4th harmonic are higher on the seat with an absorber