## 3 Results
### General Results: Key Geometrical, Aerodynamic and Performance Parameters
and GTOW have been developed in the United States, whereas the rest of the American continent develops platforms that are smaller in size and weight. Figure 8 shows the GTOW as a function of payload weight for the general category, while Figure 9 shows the same correlation with respect to NATO classification. Supplementary Table 6 sums up the statistical and correlation results for the GTOW against payload weight analysis. In Figure 8, it can be noticed that there is a very strong power fitting between GTOW and payload weight in the general category, with an R\({}^{2}\) equal to 0.965. A very good fitting is also achieved in the MALE classification, where the dispersion of available data is low. The rest of the fittings appear to have a better R\({}^{2}\) compared to Table 4, but a considerable dispersion is still present when observing each NATO category individually, leading to the conclusion that the designers need to be more careful when following the trendlines available in previous studies. \begin{table}
\begin{tabular}{c c c c c c} \hline  & **R\({}^{2}\)** & **A** & **B** & **_n_** & **Type of Fitting** \\ \hline All & 0.97 & 5.312168 & 0.972 & 0.9646 & Power \\ Micro-Mini & 0.49 & 5.5862 & 0.588 & 0.4869 & Power \\ Small & 0.73 & 9.2055 & 0.6944 & 0.734 & Power \\ Tactical & 0.69 & 20.78019 & 0.634 & 0.689 & Power \\ MALE & 0.94 & 25.45724 & 0.692 & 0.935 & Power \\ HALE-Strike & 0.57 & 2.464527 & 1.131 & 0.568 & Power \\ \hline \end{tabular}
\end{table} 
Table 6: Statistical data regarding the trend fitting for the GTOW as a function of payload weight plots. Figure 7: Wingspan as a function of GTOW with respect to region of origin. Figure 10 shows the GTOW as a function of payload weight with respect to region of origin. No major conclusions can be drawn from this chart, other than that all regions follow more or less the same trend and that no region shifts its data to a specific plot area. Figure 8: GTOW as a function of payload weight for the general category. Figure 9: GTOW as a function of payload weight with respect to NATO classification. The color code is identical to the one described in Figure 6.  
Figure 11 shows the data scatter for the empty weight parameter as a function of GTOW, and Figure 12 shows the same distribution with respect to NATO classification. Table 7 sums up the statistical data regarding the trend fitting for the empty weight as a function of GTOW plots. In this case, the level of confidence for the trendlines is higher, as no R\({}^{2}\) is calculated below 0.75 for any NATO category. However, note that this chart shows the \(W_{e}\) and not the empty weight ratio (\(W_{e}/W_{0}\)) employed by most design textbooks. Figure 13 shows the empty weight parameter against GTOW per region of origin. As is the case with Figure 11, no major deviations are observed from the main trend for any of the regions. Figure 11: Empty weight as a function of GTOW for the general category. Figure 10: GTOW as a function of payload weight with respect to region of origin. The next two figures (Figures 14 and 15) are used to present the empty weight ratio as a function of GTOW, for the general category and NATO categorized UAVs, respectively. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \(\mathbf{R^{2}}\) & \(\mathbf{A}\) & \(\mathbf{B}\) & \(\boldsymbol{n}\) & **Type of Fitting** \\ \hline All & 0.88 & 0.8105 & 0.9425 & 202 & Power \\ Micro-Mini & 0.89 & 0.7828 & 0.9666 & 40 & Power \\ Small & 0.88 & 0.5307 & 1.0418 & 65 & Power \\ Tactical & 0.91 & 0.2464 & 1.1726 & 45 & Power \\ MALE & 0.85 & 0.3778 & 1.053 & 29 & Power \\ HALE-Strike & 0.76 & 4.829 & 0.73 & 23 & Power \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Statistical data regarding the trend fitting for the empty weight as a function of GTOW plots. Figure 12: Empty weight as a function of GTOW with respect to NATO classification. The color code is identical to the one described in Figure 6.  
Figure 13: Empty weight as a function of GTOW with respect to region of origin.