# Mini Glider Design and Implementation with Wing-Folding Mechanism
## 5 Discussion  
In this study, a foldable mini-glider design and implementation was described in detail while design constraints were defined based on CanSat competition rules. By mentioning the materials used in the design and the selection criteria, the glider's mathematical model and system dynamics are presented. Flight limitations were also presented according to aerodynamic analyses, supported by design simulation results. A new method has been done and reported for more optimized operation by testing the wing deploying and folding times. Tests have been made for the reliability of the wing-folding mechanism, and a safe and easy to implement design has been done. Finally, experimental flight results were also reported to show a good match with theoretical results. Since the proposed glider has a passive flight structure and limited sensor capability due to regulations of CanSat Competition, the simulation parameters were verified by using actual experimental results via required path-following in the desired circular diameter and flight time.  
Accordingly, as a contribution to the literature, an unmanned glider designed under certain rules and constraints is described. It has been shown what should be considered in a lightweight and foldable design of a glider. The lightweight glider was designed to have a higher \(C_{L}\) and a lower \(C_{D}\) coefficient than similar studies. According to similar studies of the same size, there was no problem in transmitting data from the sensors even when it is inside of the rocket, in the container or outside the container. The wing-folding of the glider was realized by a completely passive-autonomous mechanical mechanism and fulfilled the desired objectives without any initial condition at low altitude. The designed glider can receive telemetry data and also allows flight information to be sent to the ground station. With its lightweight design and low power consumption, the glider can obtain relevant flight data from all sensors. Thus, aerodynamically, a more successful design has been made.  
In the experiments, the wings were opened successfully when glider separation from the container. If there is a delay or failure during wing deployment, the glider would not be able to fly in co-helical orbits and land. For this reason, a specialized wing-folding mechanism was presented. Simple equipments (springs-magnets) were utilized based on offered mechanism. It was also seen that it gave faster opening results compared to similar designs of the same size of folding mechanism. The deployment speed of the wings was tested with repetitive experiments (25 times) for the two different wing-folding configurations. Deployment duration was recorded by high speed camera and the strength of the mechanism was also reported.  
The oscillation caused by the momentum generated during the opening and closing of the wings has also been examined. The results were shown by the analysis, and the experimental setups in which a mechanism with fast and reliable opening of the wings were obtained. Lastly, more stable flight is shown in experimental studies than in similar examples of glider without any motor and active controller. It has been observed that a successful phugoid motion has been captured. In this mode, a continuously descending flight orbit was observed. The glider system successfully opened its wings when it left the container, just like in the test results, and successfully completed the competition goals.  
Throughout the project, [PERSON] was responsible for the implementation of the glider, experiments, COMSOL(r) analysis, and mathematical models. [PERSON] completed all manufacturing processes of the related model and ground-station interface. He was also responsible for the development of the wing-folding principles.  
**Conflicts of Interest:** The authors declare no conflict of interest.