## 6 Model Validation
### Performance Prediction Using the Proposed Model  
Based on the estimated model parameters, the performances of the sample sets were predicted to validate the proposed model. Figures 24 and 25 show the performance prediction results for each sample set compared with the results of the static thrust test. In order to estimate the effect of the armature reaction, the performance prediction results were illustrated with two cases for different values of the armature reaction factor and an ideal case in which armature reaction and thermal effects were excluded. When considering the overall trend, the effects of armature reactions were evident in the experimental results of all sample sets as compared with the ideal cases. For sample set 2, this trend was particularly significant. When the results that were obtained by applying the model for armature reaction and thermal effect were compared, the value of the appropriate armature reaction factor decreased as the size of the motor increased. In contrast, even in the same sample set, the values of the suitable armature reaction factor tended to depend on the mechanical measurement (thrust, torque, and rotational speed) and electrical measurement (terminal voltage, current consumption, and power input). For sample set 1, as shown in Figure 24a-c, the thrust, torque, and rotational speed were found to be very well fitted when the values of the armature reaction factor were applied at 2.0 \(\times 10^{6}\). However, the terminal voltage, current consumption, and power input were better fitted when the value of the armature reaction factor was 1.0 \(\times 10^{6}\), as shown in Figure 24d-f. Sample sets 2 and 3 tended to show opposite results of that of sample set 1. For sample set 2, as shown in Figure 25, the thrust, torque, and rotational speed were all well fitted when the armature reaction factor was 2.5 \(\times 10^{6}\), whereas the terminal voltage, current consumption, and power input appeared to be better at 4.0 \(\times 10^{6}\). Under the same tendency, as shown in Figure 26, sample set 3 was well fitted in terms of thrust, torque, and rotational speed  
Figure 23: Terminal voltage of the battery model and the power Supply according to the current load. when the armature reaction factor was 4.0 \(\times\)10\({}^{6}\) and, in terms of terminal voltage, current consumption, and power input when the armature reaction factor was 6.0 \(\times\)10\({}^{6}\). Figure 24: Performance prediction results of sample set 1 (T-motor U15 II with T-motor G40x13.1) compared with static thrust test results: (**a**) Thrust, (**b**) torque, (**c**) rotational speed, (**d**) terminal voltage, (**e**) current consumption, and (**f**) power input. Figure 25: Performance prediction results of sample set 2 (KDE13218 XF-105 with KDE-CF-355-DP) compared with static thrust test results: (**a**) Thrust, (**b**) torque, (**c**) rotational speed, (**d**) terminal voltage, (**e**) current consumption, and (**f**) power input. The most likely reason for this observation is thought to be the estimation error of the thermal effect by the simple thermal profiles. If the thermal effect causes the motor to suffer performance degradation, the amount of current that is consumed at the same torque will increase, while the maximum output power that can be produced at the full throttle will be reduced. In particular, it is assumed that the actual thermal profile of each sample motor was considerably different because of the  
Figure 26: Performance prediction results of sample set 3 (KDE10218 XF-105 with KDE-CF-305-DP) compared with static thrust test results: (**a**) Thrust, (**b**) torque, (**c**) rotational speed, (**d**) terminal voltage, (**e**) current consumption, and (**f**) power input. difference in cooling performance that resulted from the difference in the shape of the motor, given the opposite tendency of sample sets 1, 2, and 3.