Note: Testing methods are described in detail in the Instruction Manual. Impact Testing In order to simulate a 30^o nose dive impact, the fuselage was propelled by a pneumatic cannon at a target at the given angle. The speed was calibrated and verified with a calibration board and a semi-high speed camera. In order to verify velocity, students used the frame rate and the distance traveled. By counting the number of frames to travel the given distance, students knew the travel time. Then the equation Velocity =Distance/Time could be used to find an average velocity. This process does assume an average velocity but this assumption had little effect in the 8 feet the projectile traveled. Each test was verified to be at least 22 m/s. Pneumatic Cannon The barrel and supports of the pneumatic cannon were constructed from 2.5” square, 16 gauge steel. The tank and tubing were made with common Poly Vinyl Chloride (PVC) pipe. The control lever was made from ABS plastic on the water jet machine. Figure 8.1: Pneumatic Cannon Target The target frame was constructed from scrap 1” x 2”, 16 gauge steel. The surface was made from a scrap table top that was 1.5” particle board. The hinges are available at most hardware stores. This group designed the target to be variable from 10 to 50 degrees. This will allow engineers to test at different angles for other research. Figure 8.2: Impact Target Calibration Board The calibration board was made from medium density fiber board with steel stands. It was assembled with wings nuts for easy assembly. The board was 8 feet long with 3 inch divisions. Figure 8.3: Calibration Board and Test Configuration Impact Results Fuselage with Motor The fuselage and motor assembly were fired at over 20 m/s at the target. Upon impact the motor plate bent slightly and detached from the fuselage. Also the nose deformed slightly and separated at the point of bonding. However, the main structure of the fuselage stayed intact. Fuselage with Motor and Weight The fuselage, motor, and weight added up to 3.01 pounds as specified by the sponsor. This assembly was fired at over 20 m/s at the target. There was considerable separation and deformation at the nose and, as before, the motor mount flexed and detached from the fuselage. As with the previous test, the main structure of the fuselage stayed intact. Impact Analysis Though these fuselages suffered considerable damage, the main structures held strong. The sponsor was pleased with these results and accepted the design. This test was difficult to quantify, but was requested by the sponsor for qualitative examination of this design as opposed to a quantitative test. Bench Testing In order to ensure that the heat from the components would not affect the composite integrity, the components were assembled in the fuselage. The fuselage was clamped to a table and the motor was run for extended periods. The goal was to run at full power for at least 10 minutes. However, in this configuration, the fully charged battery would not last the full time. Thus, for Run 1 and 2, the run was ended when the motor ran erratically because of low voltage. Bench Test Results Run 1 - Full power - 5.5 minutes - No temperature change Run 2 - 50% Power - 8 minutes - No temperature change Run 3 - 25% Power - 15 minutes - No temperature change Bench Test Analysis Though uneventful, these results were very good. The engineers at AFRL, using a flat sheet of aluminum for a motor mount and no vents, had an issue with overheating of the material. Group 15’s design successfully allowed enough air to flow through the fuselage to keep the internal components cool.