# A Survey of the Effects of Vehicle Configuration on Urban Air Mobility +
## 2 Aerial Urban Vehicle Configurations and Concepts
### Vertical Take-Off and Landing (VTOL)
#### 2.2.3 Cyclocopter  
A cyclocopter uses multiple wings in the shape of fins or blades, mounted on a rotating axis like a series of pedals to generate lift force. In cyclocopters, the rotors move like a watermill or bicycle pedals and this is the reason behind their name [15]. One example of cyclocopter UAMs belongs to the Cyclotech company. Cyclotech uses cyclorotors as the main propulsion system, with target ranges around 80-120 km, enabling a more compact design of the aircraft, and therefore reducing the direct operating cost compared \begin{table}
\begin{tabular}{c c} \hline \hline
**Advantages** & **Disadvantages** \\ \hline No need for a runway (VTOL) & Low endurance \\ Design simplicity and flexibility & Low speed \\ Low price & Low efficiency in cruise flight \\ Hover capability & Robustness against faults \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Advantages and disadvantages of M = multirotors. Figure 11: Examples of multirotor UAM solutions: (**a**) CityAirbus, (**b**) CityAirbus Next Gen, (**c**) Moog Surefly, (**d**) Volocopter VoloCity, (**e**) Ehang 184.  
to existing concepts. Using such a concept provides them with 360-degree thrust control, maneuverability, and agile control. The 360-degree control of the cyclo-rotor is achieved by controlling the blades' angle of attack which enables vertical take-off and horizontal cruise flight. Figure 12 illustrates the mechanism of thrust control in cyclo-rotors [57]. In addition, precise thrust vector control of the cyclo-rotor allows a smooth transition phase without any banking or the need to change the attitude of the aircraft. The performance of cyclo-rotors increases as their speed rises. The energy consumption in cruise flight mode is much lower than that of hover mode. Thus, making the cyclo-rotor the ideal propulsion system for mid-range flight missions. In comparison to fixed-wing, tilt-wing, or tilt-rotor systems, aircraft with CycloRotors as the main propulsion system offer a reduction of the aircraft footprint of up to 75 percent [57]. Figure 13 illustrates the views of the CycloTech cyclocopter. A four cyclo-rotor equipped aircraft (current version) has been claimed to be able to carry up to about 83 kg of payload, which makes it suitable for personal urban mobility. An upgraded version is under development to carry up to five passengers [57]. Another  
Figure 12: Thrust control mechanism in cyclo-rotors [57]. Figure 13: Views of CycloTech cyclocopter: (**a**) front view, (**b**) cyclo-rotor, (**c**) side view [57]. concept is the D-Dalus by IAT21, an Austrian startup company. It is supposed to use rotating wings as the main source of propulsion for VTOL while also having an aerodynamic body to allow it to glide to safety in case of engine failure [58]. One of the prototypes built weighed around 175 kg [5], could carry a payload of 70 kg, and used four 120 HP engines to do so. The body for this prototype was constructed of carbon fiber [59]. Another example of cyclocopters that is intended for both military and civilian uses would be the Russian Advanced Research Foundation's (FPI) design which was first shown in the Army-2020 forum and then again in Army-2021 by the name of \"Cyclone-2020\". According to FPI's project manager, the design is superior to helicopters and multirotors in some pivotal aspects such as engine power requirement and payload weight [2]. Unmanned prototypes of the design have already been made for demonstrational and testing purposes. A 60 kg model of the design has already been flight tested and is said to have shown good performance in maneuverability and flight endurance. Larger manned prototypes are currently under development with a weight of 2.5 tons, a payload of 600 kg, and VTOL capabilities from both level and inclined surfaces in mind. Larger transport versions of the design with a weight of 10 tons and a payload of 4 tons have also been mentioned as possibilities at the later stages of development [60]. Table 7 summarizes the advantages and disadvantages of cyclocopter aircraft.