# Parametric Analysis for Hybrid-Electric Regional Aircraft Conceptual Design and Development
## 3 Simulation Results and Discussion
### Battery Technology Impact on Hybrid-Electric Regional Aircraft Design
#### 3.1.2 Effect of Varying Design Range  
This section describes the effect that design range variations have on the design and performance of regional hybrid-electric aircraft. First, the optimisations described in the previous section were replicated by reducing the design range to 400 nm. That value is representative of many typical missions in the regional market, as documented in [24]. We first present the results for the optimisations in which the _FoM_ is set equal to the block fuel; then, different sets of optimisations were carried out again to vary the MTOW = \(W_{c}\) constraint. In Table 3, the results related to the optima-\(m_{pb}\) configurations with a design range of 400 nm are reported. The comparison with the corresponding results obtained for the reference range (namely, 600 nm, see Table 1 and Figure 2) reveals some substantial differences. First, since the energy demand to perform a shorter mission is lower, it is trivial to obtain general reductions in fuel consumption, which is obviously also true for full-thermal configuration. Note that for the full-thermal benchmark, MTOW = 15210 kg, \(m_{fb}\) = 734 kg, and _PREE_ = 0.871 are obtained. The differences are thus mainly to be found in the effect of the _BED_ and MTOW variations. In fact, it can be observed that as MTOW increases, even substantial reductions in \(m_{fb}\) can be obtained for \(BED\) = 400 Wh/kg (see the left part of Figure 8), a circumstance that did not occur at a range of 600 nm; slight reductions as MTOW changes are also visible for \(BED\) = 300 Wh/kg, which are in any case slight, but considerably better than the results relating to the state of the art in battery technology. In particular, as MTOW increases, sharp reductions in \(m_{fb}\) are obtained, both for \(BED\) 400 and 500 Wh/kg so that, with respect to the thermal benchmark, reductions of 88% (with an increase in MTOW of 210%) are obtained for \(BED\) = 400 Wh/kg, and even reductions of 97% (with an increase in MTOW of 146%) are achieved for the \(BED\) = 500 Wh/kg case. In this scenario, there is a \(m_{fb}\) = 10 kg, i.e., only the take-off share, while the standard airborne mission is fully accomplished with only electrical power. Regarding the values of _PREE_ obtained for the \(m_{fb}\)-optimised configurations (see the right part of Figure 8), the numerical results show that in case of BED = 500 Wh/kg, the value of the _PREE_ increases until it reaches a maximum of 1.3 for an MTOW near 32,000 kg, then the trend is reversed and _PREE_ decreases. In this case, a more beneficial trade-off between the two \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline _BED_ & \(m_{fb}\) (kg) & \
\begin{tabular}{c} **MTOW** \\ **(kg\({}_{\text{f}}\))** \\ \end{tabular} & \(H_{P}\) &
\begin{tabular}{c} _W/S_ \\ **(kg/m\({}^{2}\))** \\ \end{tabular} & \(\Phi_{cl}^{t}\) & \(\Phi_{cl}^{e}\) & \(\Phi_{cl}^{t}\) & \(\Phi_{cr}^{e}\) & \(\Phi_{cl}^{t}\) & \(\Phi_{de}^{e}\) & \(\[PERSON]_{de}^{e}\) \\ \hline
200 & 718 & 18,607 & 0.136 & 325 & 0.456 & 0.525 & 0.426 & 0.367 & 0.153 & 0.244 \\
300 & 525 & 46,021 & 0.408 & 325 & 0.126 & 0.482 & 0.197 & 0.313 & 0.160 & 0.149 \\
400 & 89 & 47,204 & 0.485 & 325 & 0.118 & 0.483 & 0.01 & 0.314 & 0.09 & 0.148 \\
500 & 10 & 37,488 & 0.694 & 325 & 0 & 0.708 & 0 & 0.467 & 0 & 0.236 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Main data of \(m_{fb}\)-optimised configurations varying \(BED\) @400 nm. _FoMs_ can be selected, as a very low \(m_{fb}\) corresponds with the maximum _PREE_. In the case of \(BED\) = 400 Wh/kg, _PREE_ is almost constant for the investigated interval of MTOW, and for lower values of \(BED\), a decreasing trend is still observed, as for the case of 600 nm. Interesting considerations can also be made by evaluating the results for the case where _FoM_ is set equal to _PREE_ for the 400 nm design range.