The objective of this lab was to conduct testing on the electric motor and propeller in a wind tunnel, and to analyze the wind tunnel testing results to understand wind tunnel and thrust stand equipment as well as propulsion system efficiency. This understanding of propulsion system efficiency is crucial in designing a push or pull configuration for the AEV that is able to function in the most ideal speeds programmed to move around Jurassic Park. The wind tunnel is shown in the figure below.
Figure 1: Wind Tunnel
The figures below display the two motor configurations in the wind tunnel.
Figure 2: Pull (Tractor) Configuration
Figure 3: Push Configuration
The figures below exhibit the different equipment used to gather data from the wind tunnel.
Figure 4: Wind Speed Controller
Figure 5: Wind Speed Indicator
Figure 6: Arduino Control System
Figure 7: Power Supply
The graphs below describes the power available versus the RPM and the propulsion efficiency versus the advance ratio for each propeller type we used in lab along with the motor configuration.
Figure 8
Figure 9
The tables below show the wind tunnel data and indicates the propeller and motor configuration.
Table 1: Wind Tunnel Data with Propeller EP 2510 Pull Configuration
| Current (amps) | Thrust Scale Reading (grams) | RPM | Arduino Power Setting (%) |
| 0.19 | 1783 | 0 | 0 |
| 0.3 | 1866 | 1856 | 10 |
| 0.39 | 1881 | 2934 | 15 |
| 0.49 | 1930 | 3892 | 20 |
| 0.59 | 1971 | 4670 | 25 |
| 0.69 | 2021 | 5508 | 30 |
| 0.79 | 2064 | 6287 | 35 |
| 0.9 | 2113 | 7005 | 40 |
| 0.98 | 2170 | 7604 | 45 |
| 1.07 | 2235 | 8263 | 50 |
| 1.16 | 2310 | 8922 | 55 |
Table 2: Wind Tunnel Data with Propeller with EP 2510 Push Configuration
| Current (amps) | Thrust Reading Scale (grams) | RPM | ArduinoPower Setting (%) |
| 0 | 159.6 | 0 | 0 |
| 0.09 | 159.2 | 2095 | 10 |
| 0.18 | 159.2 | 3293 | 15 |
| 0.27 | 159.8 | 4431 | 20 |
| 0.35 | 160.2 | 5508 | 25 |
| 0.44 | 161.6 | 6706 | 30 |
| 0.51 | 162.7 | 7904 | 35 |
| 0.57 | 164.3 | 9101 | 40 |
| 0.62 | 165.9 | 10179 | 45 |
| 0.67 | 167.7 | 11377 | 50 |
| 0.71 | 169.6 | 12514 | 55 |
| 0.78 | 172.3 | 13473 | 60 |
Table 3: Wind Tunnel Data with Propeller EP 3030 Pull Configuration
| Current (amps) | Thrust Scale Reading (grams) | RPM | Aruino Power Setting (%) |
| 0.2 | 163.2 | 0 | 0 |
| 0.3 | 162.1 | 1856 | 10 |
| 0.4 | 164.5 | 2934 | 15 |
| 0.49 | 167.7 | 3952 | 20 |
| 0.59 | 172.3 | 4730 | 25 |
| 0.69 | 177.4 | 5568 | 30 |
| 0.79 | 183.4 | 6287 | 35 |
| 0.89 | 190.1 | 7065 | 40 |
| 0.98 | 196.4 | 7724 | 45 |
| 1.08 | 203.4 | 8323 | 50 |
| 1.17 | 211 | 8982 | 55 |
| 1.19 | 220 | 9760 | 60 |
Table 4: Wind Tunnel Data with Propeller EP 3030 Push Configuration
| Current (amps) | Thrust Scale Reading (grams) | RPM | Arduino Power Setting (%) |
| 0.04 | 188.5 | 0 | 0 |
| 0.16 | 186 | 2035 | 10 |
| 0.26 | 188.3 | 2934 | 15 |
| 0.37 | 191.5 | 3772 | 20 |
| 0.47 | 194.8 | 4550 | 25 |
| 0.58 | 199.5 | 5269 | 30 |
| 0.69 | 205.3 | 5988 | 35 |
| 0.8 | 211.7 | 6526 | 40 |
| 0.89 | 218.5 | 7245 | 45 |
| 0.99 | 226.5 | 7964 | 50 |
| 1.1 | 234.5 | 8622 | 55 |
| 1.23 | 242.1 | 9221 | 60 |
We also had many equations to calculate the parameters.
Equations
Calibrated Thrust Tc=0.411*(T-T0), where Tc=Calibrated Thrust (grams), T=Thrust Scale Reading (grams), and T0=Thrust Scale Reading at 0% power (grams)
Power Input Pin=V*I*(P%/100), where Pin=Power Input (watts), V=Voltage (volts), I=Current (amps), P%=Arduino Power Setting
Power Available Pout=Tc*v, where Pout=Power Available (watts), Tc=Calibrated Thrust (Newton), and v=Wind Tunnel Velocity (m/s)
Thrust m*a (Newton), where m=mass (kg) and a=acceleration due to gravity (9.81 m/s2)
Propulsion Efficiency ηsys=(Pout/Pin)*100%, where ηsys=Propulsion Efficiency, Pout=Power out (watts), and Pin=Power in (watts)
In the final System Analysis Lab, the AEV was tested in a wind tunnel to determine its propulsion efficiency. Parameters used in this lab introduced in the previous lab include velocity and RPM, which the propulsion efficiency depended on. New parameters, such as calibrated thrust, power input, and power available all contribute to ascertain the propulsion efficiency. Unit conversions were provided and utilized to calculate the new parameters. By examining carefully the power expended in relation to the distance yielded from it, it is possible to maximize the AEV’s efficiency in the presence of different factors, including wind and propeller configuration specifically tested in this lab.