# A Survey of the Effects of Vehicle Configuration on Urban Air Mobility +
## 2 Aerial Urban Vehicle Configurations and Concepts
### Hybrid
#### 2.3.5. Gyrodyne
\begin{table}
\begin{tabular}{c c} \hline \hline
**Advantages** & **Disadvantages** \\ \hline Fairly simple design & Less range relative to HTOL aircraft \\ Capable of both VTOL and HTOL & Slower than HTOL aircraft \\ Higher cargo capacity compared to VTOL aircraft & High fuel consumption in VTOL phase \\ Higher range compared to VTOL aircraft & Noise problems during VTOL \\ No need for a tail rotor & No need for a tail rotor \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Advantages and disadvantages of gyrodyne. Figure 19: Historical and newly developed gyrodynes: (**a**) Fairey rotodyne, (**b**) [PERSON]’s gyrodyne. uses a large rotor for VTOL performance and four large electric propeller motors for horizontal flight. As mentioned with Fairey Rotodyne, the rotor becomes unpowered once enough forward airspeed is attained and engines also play the role of torque counteraction. Furthermore, in order to address the noise problem that comes with gyrodynes, the ROSA's rotors operate at slow speeds (to the point that their rotation can be distinguished by the naked eye) which makes it considerably quieter than other Gyrodnes and even many regular helicopters and fixed-wing aircraft (up to 50-66 percent in some cases as claimed by [PERSON]). In addition to providing part of the lift during the cruise flight, the unpowered rotor ensures the possibility of a safe landing in case of engine failure. Similar to the Fairey Rotodyne, the ROSA design is fairly low maintenance as its rotor mechanism is far simpler than that of a helicopter and is more in league with fixed-wing aircraft on that front. A problem that electric UAM designs face at the moment is battery performance. Batteries need to not only improve in capacity but also recharge speed. Therefore, as battery designs become more efficient, designs like the ROSA become more and more viable and economical [96]. [PERSON] has also tried to increase the performance of its design by LevelFly technology. The entire top pylon holding the main rotor in this aircraft is designed to tilt, allowing the cabin to easily be balanced no matter how many passengers are on board, or where they sit. This should also help keep things comfortable in the cabin during the transitions between VTOL and winged flight, a complex phase that could involve some pretty uncomfortable tilting in other eVTOL designs. Due to the relative obscurity of this configuration, not much research has been done assessing its performance under faulty conditions. Hence, one can only extrapolate from the similarities in other configurations and try to make a few conclusions. The take-off and landing phases of flight are similar to that of a helicopter; therefore, considerations that were mentioned in Section 2.2.1 also apply here. Furthermore, during cruising flight, the behavior is very similar to that of a fixed-wing aircraft, meaning that a partial engine or control surface failure can be compensated for, through trimming, control reallocation or other methods that were previously mentioned in Section 2.1.1 and in case of a complete loss of forward thrust, although an emergency land would still be necessary, due to autorotation, landing can be done in smaller areas [97] or even vertically if the rotor is still operational. Finally, the hard-to-predict nonlinearity of the autorotating rotor that was mentioned in Section 2.1.4 also has an effect during cruise flight; however, due to the greater portion of lift being attributed to the wings in this phase, it should most likely be less problematic compared to a gyroplane.