# A Conceptual Design Methodology for e-VTOL Aircraft for Urban Air Mobility
## 3 Comparisons with Literature Data  
To compare the design workflow, the three tilt-wing e-VTOL aircraft described in [45] has been considered. The same assumptions of the reference paper have been introduced, and information not directly provided (e.g., wing taper ratio, fuselage length and diameter) has been reasonably assumed or derived from the reference source. The comparisons between the results computed with the proposed design procedure and the reference data from [45] are shown in Tables 5-7. Figure 8: Scatter plot of samples and linear regression model of the propeller mass vs maximum power absorbed by the propeller. The comparisons highlight that the proposed methodology:  
* estimates a higher OEW/MTOW fraction since it calculates each single component by using physic-based equations, whereas in the reference paper a quite simple relation on OEW/MTOW fraction is assumed, and it is not stated if it accounts for components such us cables, TMS, BMS, etc. ;
* shows a higher MTOW estimation in comparison to the reference paper in all the examined cases, which is mainly due to the higher OEW/MTOW fraction estimation; \begin{table}
\begin{tabular}{l l l l} \hline \hline \multicolumn{1}{c}{**Aircraft**} & \multicolumn{3}{c}{**Requirements and Assumptions**} & \multicolumn{1}{c}{**Polar Curves**} \\ \hline \hline \multirow{6}{*}{Architecture: **tandem wing**} & Range [km] & \(100\) & \\ \cline{2-4}  & Range [km] & \(100\) & \\ \cline{2-4}  & \(M_{\text{pay}}\) [kg] & \(400\) & \\ \cline{2-4}  & \(P/W\) [W/kg] & \(284\) & \\ \cline{2-4}  & \(W/S\) [kg/m\({}^{2}\)] & \(126\) & \\ \cline{2-4}  & \(T/A\) [kg/m\({}^{2}\)] & \(75\) & \\ \cline{2-4}  & \(\boldsymbol{OUTPUT}\) & **Computed** & **Ref.** & \(\boldsymbol{\Delta\%}\) \\ \cline{2-4}  & MTOW [kg] & \(1877\) & \(1768\) & \(+6\%\) \\ \cline{2-4}  & \(M_{\text{hutt}}\) /MTOW & \(24\%\) & \(27\%\) & \(-3\%\) \\ \cline{2-4}  & OEW/MTOW & \(55\%\) & \(50\%\) & \(+5\%\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison with the four-passenger configuration of the reference paper [45]. \begin{table}
\begin{tabular}{l l l l} \hline \hline \multicolumn{1}{c}{**Aircraft**} & \multicolumn{3}{c}{**Requirements and Assumptions**} & \multicolumn{1}{c}{**Polar Curves**} \\ \hline \hline \multirow{6}{*}{Architecture: **tandem + tail**} & Range [km] & \(100\) & \\ \cline{2-4}  & Range [km] & \(100\) & \\ \cline{2-4}  & \(M_{\text{pay}}\) [kg] & \(600\) & \\ \cline{2-4}  & P/W [W/kg] & \(284\) & \\ \cline{2-4}  & \(W/S\) [kg/m\({}^{2}\)] & \(126\) & \\ \cline{2-4}  & \(T/A\) [kg/m\({}^{2}\)] & \(75\) & \\ \cline{2-4}  & MTOW [kg] & \(1200\) & \(1005\) & \(+19\%\) \\ \cline{2-4}  & \(M_{\text{hutt}}\) /MTOW & \(24\%\) & \(28\%\) & \(-4\%\) \\ \cline{2-4}  & OEW/MTOW & \(59.3\%\) & \(52\%\) & \(+7.5\%\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Comparison with the six-passenger configuration of the reference paper [45]. \begin{table}
\begin{tabular}{l l l l} \hline \hline \multicolumn{1}{c}{**Aircraft**} & \multicolumn{3}{c}{**Requirements and Assumptions**} & \multicolumn{1}{c}{**Polar Curves**} \\ \hline \hline \multirow{6}{*}{Architecture: **using-tail**} & Range [km] & \(100\) & \\ \cline{2-4}  & \(M_{\text{pay}}\) [kg] & \(200\) & \\ \cline{2-4}  & P/W [W/kg] & \(284\) & \\ \cline{2-4}  & \(W/S\) [kg/m\({}^{2}\)] & \(126\) & \\ \cline{2-4}  & \(T/A\) [kg/m\({}^{2}\)] & \(75\) & \\ \cline{2-4}  & \(T/A\) [kg/m\({}^{2}\)] & \(75\) & \\ \cline{2-4}  & \(M/A\) [kg/m\({}^{2}\)] & \(75\) & \\ \cline{2-4}  & \(\boldsymbol{OUTPUT}\) & **Computed** & **Ref.** & \(\boldsymbol{\Delta\%}\) \\ \cline{2-4}  & MTOW [kg] & \(2685\) & \(2534\) & \(+6\%\) \\ \cline{2-4}  & \(M_{\text{hutt}}\) /MTOW & \(24\%\) & \(27\%\) & \(-3\%\) \\ \cline{2-4}  & OEW/MTOW & \(54\%\) & \(49\%\) & \(+5\%\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison with the two-passenger configuration of the reference paper [45]. * slightly underestimates the battery mass fraction, but the discrepancies are small.