Alabama A&M University Rocket Program 2010-2011

1. Preliminary Design Review Presentation November 19, 2010 Alabama A&M University Rocket Program 2010-2011

2. Overview 1. Vehicle Specifications 2. Vehicle Safety and Verification 3. Motor Selection 4. Motor Safety and Verification 5. Payload Design 6. Payload Safety and Verification 7. Recovery System 8. Recovery System Safety and Verification

3. Vehicle Specs • Dimensions • Airframe Diameter: 6.0 in. • - Rocket Height: 7.5 ft. • - Space must be allocated for the 30 in. rocket engine • - Space must be allocated for 125 in. main parachute and 30 ft. shock cord • - Space must be allocated for 24 in. drogue parachute and 20 ft. shock cord • - Space must be allocated for payload and electronics • - Materials Selection: G-10 Fiberglass • - Lightweight: Fiberglass is most common in lightweight vehicle applications • - Durability: Low maintenance, reduced chances of zipper, enhanced reusability

4. Stability Analysis “Rocksim” • - Spectrum Stability Margin: 4.25 (Overstable) • - Rocksim simulates Barrowman Equations Fins Number of Fins: 4 Root Chord Length: 11.5 in. Tip Chord Length: 1.5 in. Sweep Angle: 48 Degrees Nosecone Length: 6 in. Base Diameter: 6 in.

5. Rocksim Flight Simulation Maximum velocity & acceleration before burnout Altitude Constant Velocity & Acceleration at Descent 0 Velocity & Acceleration at Apogee

6. Vehicle Safety and Verification Tests, Analysis & Buildup 1. Test solid motor for model flight. 2. Pre-calculate the chamber pressure from ejection charge. 3. Understand maximum stress of G-10 Fiberglass. 4. Use long set epoxy for high stress points on airframe & couplers. 5. Use correct shear pins for ejection. 6. In motor retention use welds and bolts.

7. Vehicle Safety and Verification “Failure Analysis”

8. Motor Selection Motors of Choice: 1.Aerotech Rockets L-850W 2.Loki Research Rockets L-930 Specs Chart

9. Motor Safety & Verification Steps to success • Understand ALL safety rules and regulations behind solid • motor firing. • 2. Build a universal test stand for various motor configurations. • 3. Perform the proper safety checks for the launch equipment. • 4. Team must gain knowledge of all motor components. Launch Equipment Video

10. Payload Design “Components” • GPS/ Tracker System • Tracking the rocket • HOBO Data Logger • Temperature Data vs. Altitude • Flight Trajectory • Bohlender Graebener Planar Tweeter • Sound pressure Data vs. Altitude

11. Objective: To look at the convection effects of the external temperature T1 when the velocity of the rocket changes.   Given: T1 and T2 are point temperature values. Assumption: -The air is static until the rocket passes elevation of T1 Limits: -0°C (32°F) or above 50°C (122°F)  Items: -HOBO Temperature probe -HOBO Temperature Data logger Payload Design

12. Payload (cont’d) • BohlenderGraebener Neo3W Planar TweeterObjective: Transducer used to generate sound pressure in an enclosed chamber. • Features high magnets, diaphragms, and an etched planar aluminum conductor used to reproduce high frequencies with great detail and controlled dispersion. • Uses a uniform magnet system. • Radiates throughout the surface of the driver

13. Payload Safety & Verification “Failure Modes”

14. Recovery Systems “General Breakdown” Attachment Scheme Coupler (Houses Altimeters) Main Parachute Compartment Bulkhead Plates Drogue Parachute Compartment

15. Recovery Systems “Parts” • - Use 2 Perfect Flight MAWD barometric pressure sensing altimeters • - 24” Tac-1 Drogue Parachute: (Drogue Parachute Deployment) • - 125” Tac-1 Parachute: (Main Parachute Deployment) • - 30 ft Kevlar Shock Cord: (Main Parachute Deployment) • - 20 ft Kevlar Shock Cord: (Drogue Parachute Deployment)

16. Recovery Systems Safety and Verification Dual Deployment Avionics Test: 1. The dual deployment avionics will be ground tested and flight tested. The ground test will consist of placing the altimeters in a glass jar with Christmas lights installed to simulate igniters and a fresh 9V battery with a punch balloon on top. The balloon will be taped around the top of the glass to prevent air from escaping. With the altimeter armed, pull the balloon and release, the Christmas lights should light up indicating a properly functioning altimeter. The balloon pulling is similar to a decrease in pressure which is what barometric altimeters read during flight. 2. The flight test will be to load the altimeters in a scale rocket with motor ejection active. The delay grain on the solid motor should be set to the max, and the altimeter will deploy before the motor in a nominal situation. Another live charge should be placed in the forward end of the rocket with a live charge to separate the air frame allowing the second chute to deploy. The parachute will be the same size, and the flight will go 2500-2800ft.

17. Safety & Environment “Ejection Force” An ejection pressure of 10 psi has been selected as the starting pressure for ground testing. The past ground test have shown that a separation distance of 3 feet is sufficient. The Ejection Force, F (lb), for ejecting the main chute is: F= P*πr2 Where, P is the chamber pressure, psi, and r is the radius, in. Black Powder (BP) Calculations C * D * D * L = grams of BP Where: C is a constant that is determined based on the pressure D is the airframe diameter L is the length of the body tube to be pressurized The above calculations show that to attain a 10 psi pressure for the main compartment 3 grams of black powder will be needed and about 2 grams for the drogue compartment. The back-up charges are increased by one gram during flight.

18. Questions ???