PRELIMINARY DESIGN AND CALCULATION
4.1 Benchmark | Aircraft
To get the optimum behaviour of our system or design, parametric study is carried out. Parametric study is a systematic exploration on how the performance of a design varies with changes in its parameter. This method is widely used in engineering and design fields to optimise the behaviour of a system under different scenarios. By highlighting key parameters and comparing the design with existing products available in the market, we can make decisions about the optimal design given a set of conditions. In this section, we collected data from 21 commercial UAVs typically for FPV purposes as the parametric research to perform analysis.
Table 4.1 Parametric Study Data Collection (Weight & Wingspan)
Table 4.2 Parametric Study Data Collection (Cruise Speed, Range, Endurance)
4.2 Parametric Study
In this section, we compare the different performance metrics to identify the trends, optimal configurations based on benchmark drones. By carefully identifying the trend, we are able to make reliable predictions on the general performance of the drone under different conditions. It helps us to get the initial design and specification of our drone.
Figure 4.1 Graph of Endurance against Weight
Based on Figure 4.1, There is a linear relationship between the weight and the endurance of any given UAV in general. Based on this information, our UAV is designed to have an estimated endurance of 90 minutes or 1.5 hours. The trend shows that for endurance of 1.5 hours, the general weight is around 5 kg. This is specially designed to maximise the efficiency as a tourism based drone will not have to fly for an extended period over very high altitudes. In return, the aircraft becomes much more viable on running at a much lower capacity battery with all the onboard equipment without sacrificing a higher payload upon takeoff.
Figure 4.2 Graph of Range against Weight
The Figure 4.2 represents the trend of range against weight of the studied UAVs in comparison to each other. The general trend is a linearly non proportional, small increment in range for the increase in weight. Taking into account this trajectory, our UAV is designed to give us a 50 km range with a MTOW= 5 kg to maximise the efficiency to use the least amount of power while being able to complete a full round of flight without needing to recharge.
Figure 4.3 Graph of Cruising Speed against Weight
For cruising speed, this drone is set at a cruising speed of 20 m/s for efficiency of the battery. Based on Figure 4.3, for a UAV that flies at 20m/s, the general weight for the UAV is around 5kg together with the payload. The initial weight estimation is 5 kg based on the previous three (3) graphs in Figure 4.2(a), 4.2(b), and 4.2(c) and the performance we want to achieve for our UAV.
Figure 4.4 Graph of Weight against Wingspan
Based on Figure 4.4, it shows that generally as the weight of a drone increases, so does its wingspan. For a drone with weight 5 kg with its payload, the wingspan can be estimated where this weight intersects with the trendline which gives us 2m. While the trendline predicts wingspan based on weight, actual drone wingspans may vary due to other design factors.
Figure 4.5 Graph of Range against Wingspan
Based on the wingspan we estimated with the previous graph, we identify the trend that for wingspan of 2 m, the general range for the UAV can go up to 50,000 m or 50 km. This range is within the performance we want for our UAV.
In conclusion, our drone design and specifications have been carefully determined based on the analysis of various performance metrics and trends as observed in benchmark drones. We have prioritised endurance, aiming for a 1.5 hour flight time in 5 kg MTOW, as it aligns the linear relationship between weight and endurance. This configuration ensures the efficiency and sufficiency of the range, allowing for a 50 km range without the requirement for frequent charging. Our cruising speed of 20 m/s is chosen for optimal battery efficiency, and while there are multiple drone types within the desired parameter range, we have selected a design that strikes the right balance between the altitude potential and legal constraints. In addition, our wingspan estimation aligns with weight based trends, though actual wingspan may vary due to other design considerations. Overall our drone design is well informed and tailored to meet the specific requirements of UAV.
4.3 Aircraft Specification and Configuration Options
Table 4.3 Horizon Hawk Design Specifications
After decided the dimension and material that will be used for our drone, afterward we finalised our drone design :
Wing Configuration :
Wing Position: High-Wing, high-wing position gives good stability in low speed and provides good lift to drag ratio and also has better capacity for gliding long distances.
Wing Shape: Flat wing with straight leading and trailing design, we chose this design due of easy maintenance and fulfilled our aim to create drone which can fly high with low cruising speed, also we modify the tip of the wing with vortex cancelation to reduce drag during the flight
Airfoil: NACA 2412, 2412 meaning is 2% of maximum chamber that is located at 40% from leading edge and 12% of maximum thickness. Reason we chose this type of airfoil is because it provides a good lift to drag ratio, obviously we can add more lift by increasing the maximum chamber but the trade off point will be generating more drag and instability due to flow separation at the back of the wing.
Tail Configuration :
Shape: Conventional Tail, we chose this shape to reduce the cost of produce and maintenance due to simplicity. Conventional tails also give us enough to achieve what we want to aim for our drone, conventional tail give effective control at low speed and this shape provides us the tendency of natural longitudinal stability which helps pilots to control the drone.
4.4 CAD Drawing
Figure 4.6 CAD drawing
