JJPL Model Rocketry 2024-25 Study Guide
Notes
The JJPL Model Rocketry program emphasizes safety and teamwork in all rocket launches.
Key concepts include understanding rocket propulsion, aerodynamics, and recovery systems.
Students will participate in hands-on workshops to build and launch their own model rockets.
Important dates:
Initial design submission: September 15, 2024
First launch event: October 20, 2024
Final project presentation: May 5, 2025.
Page 1-2: Fundamentals
Exam Details:
Approximately 15 questions, 35 minutes.
Recommended to study all fundamentals.
Key Concepts:
Model Rocket: Understand its definition and components.
Rocket Science Basics:
Propellant: Combines fuel and oxidizer.
Thrust: Force propelling the rocket.
Drag: Resists motion through a fluid.
Weight: Force of Earth's gravity.
Lift: Opposes weight.
Page 3-4: Design and Stability
TARC Design Process:
Tools like OpenRocket and CAD play critical roles.
Stability: A rocket stays upright due to balanced center of gravity (CG) and center of pressure (CP).
Clustering:
Uses multiple engines for heavier payloads.
Key factors include motor ignition sequence and power supply.
Rocket Staging:
Increases performance by separating spent stages.
Boosters are discarded after burnout.
Page 5: NAR Safety Code
Safety Measures:
Use electrical launch systems with safety interlocks.
Restrictions on rocket weight, propellant, and materials.
Avoid launching at targets, clouds, or near aircraft.
Page 6: Aerodynamics and Materials
Fins:
Grain direction critical for strength in balsa wood fins.
Plywood fins are more versatile.
Nose Cones:
Shapes influence drag and stability.
Base Drag:
Larger diameters increase drag.
Boat tails can reduce this effect.
Page 7: Motor Types
Rocket Motors:
Black Powder Motors: Common in small rockets.
Composite Motors:
Single-use: High-temp plastics, rubber-like fuel.
Reloadable: Same fuel, allows for reuse.
Hybrid Motors: Use solid and liquid/gas propellant.
Page 8: Vibration Isolation
Dampening Systems:
Wadding: For smaller rockets.
Liquid isolators: Ideal for mid-size rockets.
Spring-mass systems: Stabilizes heavy payloads.
American Rocketry Challenge Rules:
Suggested review for relevant questions.
Page 9: Additional Resources
Video guides, safety resources, and design manuals.
Test
What is the primary function of a rocket's propellant?
(A) Reduce drag
(B) Generate thrust
(C) Balance weight
(D) Stabilize lift
What does the center of pressure represent in a rocket?
(A) The balancing point of the rocket.
(B) The location where all aerodynamic forces act.
(C) The total weight of the rocket.
(D) The point of maximum thrust.
Which material is NOT recommended for model rocket fins?
(A) Plywood
(B) Balsa wood
(C) Aluminum
(D) Basswood
What safety measure must be followed if a rocket fails to launch?
(A) Attempt another launch immediately.
(B) Wait 60 seconds and disconnect the power.
(C) Approach the rocket with the igniter on.
(D) Reset the launch system and retry.
Why are boat tails used on rockets?
(A) To improve thrust.
(B) To reduce base drag.
(C) To stabilize lift.
(D) To enhance CG location.
True/False
Black powder motors are the most commonly used motors for model rockets.
The grain direction in balsa wood fins affects their strength under force.
Rockets with hybrid motors remain stable as propellant is depleted.
The NAR safety code allows rockets with flammable payloads.
Liquid isolators are recommended for small-scale model rockets.
Short Answer
Describe the primary advantage of clustering motors in rocketry.
What are the two main characteristics that determine a rocket's stability?
Explain the function of a reloadable composite motor.
Why is it necessary to balance the CG and CP in rocket design?
List two NAR safety code rules related to rocket construction.