## 5 Conclusions  
A key area of interest for hybrid power systems in aircraft is in VTOL and multi-rotor applications. It is in these areas where the quicker response time seen in the ATC mode is vital. It is also essential that the pilot is not directly responsible for controlling the turbine power output magnitude for VTOL and multi-rotor flight. Each of the VTOL rotors operates at different power levels to maintain steady and level flight, which is a power source that can react to the changing demands in real-time. The pilot controls the other four primary controls (roll, pitch, yaw, and throttle). Adding a fifth control input, which must be carefully balanced, would overburden the pilot during flight. From the pilot perspective, ATC is generally preferred in all flight cases. There are situations, however, where DTC would be advantageous. An example of when DTC could be utilized is using a conventional, fixed-wing aircraft. The pilot could directly control the turbine and allow the electric propulsors to respond accordingly based on the power made available by the turbogenerator at any given time. Using DTC can save weight compared to ATC configurations by not having switching circuitry or additional power batteries. Fixed-wing aircraft have a much more responsive throttle with the ATC control scheme than the DTC. The more responsive ATC scheme is generally preferable to the pilot. In other words, the ATC control scheme more accurately imitates battery power output, whereas the DTC scheme behaves more like a turbine. ATC offers additional advantages to safety. The active control scheme has the potential to provide better instrumentation and state determination for the turboelectric system. This instrumentation can govern the turboelectric system and ensure it is behaving correctly and not risking damage to the rest of the power system. Having a battery in the loop for a VTOL system can also add redundancy by ensuring a VTOL aircraft can land even if the turbine fails in flight. The most extreme example of throttle lag was assessed in this paper when the turbine engine was run at the maximum throttle until the load was entirely cut. Even with a battery in the loop, a voltage spike was observed when this was performed. If the battery were not integrated into the system to receive the current dissipation, the voltage spikes would have been more severe. The voltage increase mentioned above can be seen in Figure 14, where the voltage did not exceed the range a 12S battery would tolerate. Inevitably, the turbine will briefly produce more power than is commanded by the system in certain conditions. Having a battery integrated into the main power supply ensures that voltages do not rise beyond system capabilities. It is also essential that the battery is appropriately selected to ensure sufficient charge and discharge rates. Another critical metric is a battery's amperage-hour capacity to ensure the endurance required to fulfill the desired mission. This paper lays the groundwork for further work for the safe integration of turboelectric power plants into unmanned aircraft. Bench Test Stand Design, J.B., J.D., J.J., T.R. and K.R. ; Battery Circuit Design, J.D. and J.B.; Control Software, J.B.; Testing and Validation, T.R. and J.B.; Data Reduction, T.R. ; Draft Preparation, J.B., J.J. and T.R. ; Review and editing; K.R. ; Supervision and Project Administration, K.R. All authors have read and agreed to the published version of the manuscript. This research was funded by the Federal Aviation Administration, grant number 692M15-20-C-00012. The data presented in this study is available on request from the corresponding author. The data is not publicly available without a coordinated release from the Federal Aviation Administration. The authors thank undergraduate students [PERSON] and [PERSON] for support in the design and fabrication of the turboelectric system test stand. **Conflicts of Interest:** The authors declare no conflict of interest.