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70 -20-10 0 10 20 -20 -10 0 10 20
Vertical velocity, ft/sec Vertical velocity, ft/sec
Figure 46. Phase-plane portrait for configuration V7. Figure 49. Phase-plane portrait for configuration V10.
Subjective Performance Data
Figure 50 shows pilot motion-fidelity ratings along with the postulated boundaries of Sinacori (ref. 44). The pilots unanimously rated the high-gain, low-washout configura-tions V1 and V2 as having high fidelity. If either the gain was reduced (as in V5) or the phase distortion increased (as in V3), one of the three pilots reduced his rating to medium. When a combination of this gain and phase distortion was examined, that is, configuration V6, the ratings dropped on average across one level. However, one of the pilots did not perceive differences between the V3 or V5 configuration and the V6 combination.
0.0 0.2 0.4 0.6 0.8 1.0 Gain @ 1 rad/sec
The next individual changes in gain or phase from the V3 and V5 cases to the V4 and V7 cases produced, on average, a decrease from high to medium fidelity. However, a combination of these effects, encompassed by the V9 configuration, produced unanimously low fidelity ratings. Unsurprisingly, the fixed-base configuration, V10, also produced unanimously low fidelity ratings.
These ratings suggest that for this task, the fidelity criterion for the vertical axis appears to decrease from high-gain/low-phase-distortion in a direction toward the fixed-base case. The combination configurations V2, V6, and V9 result in ratings predicted by the criterion.
However, either reducing the gain or increasing the phase distortion resulted in fidelity ratings better than predicted, on average.
Combined Results
It is reasonable to suggest a revision to the Sinacori criterion (ref. 44) if objective performance, subjective pilot fidelity ratings, and subjective pilot comments are consistent. Each of the configurations is discussed, and when a consistency exists that does not align with the criterion, then a modification to the criterion is suggested.
With the full-motion case, configuration V1, pilots were consistent in their comments that they achieved desired performance, that compensation was minimal to moderate, and that they felt that they could be very aggressive with the vehicle. All ratings were high fidelity, and the objective performance was good.
For the configuration with a slight decrease in gain and an increase in phase distortion, V2, the comments indicated that a difference was noted. Two of the three pilots noticed a slight decrease in performance, and the compensation increased over that of the V1 case. Yet all pilots rated the configuration high fidelity, since they felt is was “close to visual flight.” Here is where the fidelity definitions could be made more precise, because a pilot is faced with a potential dilemma with a configuration that has noticeable but not objectionable differences (medium fidelity defini-tion), yet is close to visual flight (high fidelity defini-tion). Pilots apparently felt that when it was necessary to group the ratings into three categories, the V2 configura-tion was in the most favorable category. Yet they all perceived a difference. It appears that the pilots may have been sensitive to the differences in the immediate accel-eration because of collective input. This initial accelera-tion is proportional to the high-frequency motion gain, and it is reasonable that the 10% change between these configurations could be noticed. It is also reasonable that the variation was not objectionable.
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本文链接地址：Helicopter Flight Simulation Motion Platform Requirements(36)
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