This Thursday, the Aeronautics Club, led by Jeremy Simoes, had their 3rd lecture in a series on rocketry. This semester, the club is focusing on rockets. By the end of the series, the group will be able to build their own model rockets and enter into a competition.
Simoes began the third lecture by picking up from the second lecture, which was on rocket anatomy. A rocket consists of three sections: the nose block, the upper body, and the payload section. The upper body is the most difficult part of the rocket to construct. The mid-section of the rocket includes the parachute, shock cord, and most importantly, the rocket motor. Simoes then played a video of a rocket igniting, and explained the general recovery method. A rocket goes through the liftoff, acceleration, and climb phase before ejecting what would soon be returned to the ground. The lower body has the tube coupler and launch lug of the rocket. The motor mount is a tube with centering rings so that the motor can stay in the right place. The lower body also includes a thrust ring, so gas can escape.
After explaining the rest of rocket anatomy, Simoes moved onto the third lecture, which covered the Center of Pressure/Gravity. He began by telling the group about the upcoming Stevens Physics Society Demonstration Day and encouraged the group to choose among a variety of aerospace projects for it. The group chose rocket gliders, which is something they will be working on during the next few weeks. He then spoke about L-Beams, beams with the acting and reacting force on different lines. The group completed an L-beam problem before moving onto center of gravity and pressure. The center of gravity or an object is the point at which all forces are acting, and the center of pressure is the point at which all pressure is acting. To calculate these points, the rocket is split into four sections and each of the section’s centers is added. To stabilize a rocket, the center of pressure must be lower than the center of gravity; otherwise the center of gravity will tilt and move the rocket. The group also learned how to calculate drag, the friction of the entire rocket as it moves throughout the air.
The last topic was fin design. Fins, the technical wings of the rocket, affect velocity depending on their thickness and height. Because of all the variables involved, Simoes decided to simulate a fin cord design the week after rather than do it with the group. Fins have both direct and indirect stress, and are affected by the L-beam forces. When calculating center of gravity and pressure, there must also be a requirement that the fin does not break and does not move.
Simoes will be leading the fourth lecture next week on rocket hulls.
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