The purpose of this project is to attain the Level 1 High Power Rocketry Certification from the National Association of Rocketry (NAR), as noted in [3]. This is a requirement for buying an H and I motor and necessary for more advanced certification levels. The motor must be within 160.01 to 320.01 Newton-seconds of impulse (classified as H to I motors), and the rocket must weigh below 53 ounces to abide by FAA regulation. In addition, it must contain a standard parachute recovery system and pass inspection by a certification team. The rocket will be evaluated for stability during ascent, recovery system deployment, and safe recovery. If successful, NAR is to sign and approve the paperwork necessary for certification.
The achievement of this certification is demonstrating the ability to develop and demonstrate the engineer has the necessary knowledge and skills to safely construct, prepare, and launch rockets using mid-power motors.
| Launch Vehicle Summary | |
|---|---|
| Rocket Name | EF-1 |
| Predicted Apogee | 2270 ft |
| Motor Selection | H135W-14A |
| Max Diameter | 2.68” |
| Length | 35.8” |
| Wet Mass | 35.3 oz |
| Dry Mass | 31.0 oz |
| Date Launched | Jaunary 11, 2026 |
| Parachute Shroud Line Length Diameter | 48” |
| Parachute Shape | Hexagon |
The EF-1 rocket is being developed primarily to experiment with and validate passive roll control, achieved through the addition of carefully canted fins. Its design is a thoughtful optimization, achieving a crucial balance between high performance, affordability, and visual appeal. The rocket is being constructed using a variety of structural materials, from aluminum and engineered plywood for core strength to various durable plastic components.
Due to the abundance of options, weighted decision matrices were employed to finalize the material selection process. Weighted decision matrices provide a structured quantitative way to defensively and systematically choose materials while maximizing objectivity and minimizing bias.
A weighted decision matrix contains an objective characteristic being compared across all materials, along with a weighting factor to account for its importance on the overall decision. The magnitude is given for each material in its corresponding unit which is shown in the parameter column.
The objectives characteristics were chosen to be important factors required for performance and assembly. Density is included to account for differences in weight. Cost is included due to a limited budget. Ultimate tensile strength (UTS) and young’s modulus (E) serve to ensure the rocket has sufficient structural integrity to survive the harsh aerodynamic conditions.
Manufacturability was also considered and ranked from one to three where one is the worst manufacturability, two is better, and three is best. Codes start with M and a number were used to denote the manufacturability score due to the space constraints on the table. M1 refers to ease of manufacturability in cutting. The airframe is to be cut to exactly two feet in length. M2 refers to how it can easily the material can be epoxied. Some materials cannot be glued well, while others require significant sanding to work. Lastly, M3 refers to safety and how dangerous it is to work with sanding.
A score from zero to ten ranks each objective proportionally where ten is the best score. The formula for the maximizing and minimizing cases are shown below. Density and cost are minimizing factors, because ideally a lighter rocket with lower cost is better. On the other hand, the ultimate tensile strength, young’s modulus, and manufacturing rankings are maximizing objectives because we want these to be as high as possible.
$$\text{score}=\frac{10\times \text{design magnitude}}{\text{highest magnitude}}(\text{Maximizing Parameter})$$
$$\text{score}=\frac{10\times\text{lowest magnitude}}{\text{design magnitude}}(\text{Minimizing Parameter})$$
The value multiplies each score by a weighting factor (WF) to account for the set importance of each parameter. Density has the lowest WF at 5%, while other parameters unrelated to manufacturing are at 10%. Manufacturing parameters are set greater than or equal to 20% because we are limited by time and equipment. Density was put at the lowest weighting factor of 5% because apogee is not a main priority for this flight.
$$\text{value}=\text{score}\times\frac{\text{weighing factor}}{100}$$
The overall value sums all the values in the column and is the final number examined for the material selection assessment.
$$\text{overall value}=\sum^{n}_{i=1}\text{value}_{i}$$
| Decision Matrix | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Airframe Material | Aluminum [1] | Cardboard [2] | BlueTube [AA] | Carbon Fiber | ||||||||||
| Objective | WF | Parameter | Mag. | Score | Val. | Mag. | Score | Val. | Mag. | Score | Val. | Mag. | Score | Val. |
| Density | 5% | g/cm³ | 2.7 | 2.6 | 0.1 | 0.7 | 10.0 | 0.5 | 1.1 | 6.4 | 0.3 | 1.6 | 4.4 | 0.2 |
| Cost | 10% | USD | 53.8 | 1.9 | 0.2 | 10.3 | 10.0 | 1.0 | 35.7 | 2.9 | 0.3 | 300.0 | 0.3 | 0.0 |
| UTS | 10% | MPa | 90 | 1.8 | 0.2 | 15 | 0.3 | 0.0 | 115 | 2.3 | 0.2 | 500 | 10.0 | 1.0 |
| E | 10% | GPa | 70 | 6.7 | 0.7 | 4 | 0.4 | 0.0 | 10 | 1.0 | 0.1 | 105 | 10.0 | 1.0 |
| M1 | 25% | Rank | 1 | 3.3 | 0.8 | 2 | 6.7 | 1.7 | 3 | 10.0 | 2.5 | 1 | 3.3 | 0.8 |
| M2 | 20% | Rank | 2 | 6.7 | 1.3 | 3 | 10.0 | 2.0 | 3 | 10.0 | 2.0 | 2 | 6.7 | 1.3 |
| M3 | 20% | Rank | 2 | 6.7 | 1.3 | 3 | 10.0 | 2.0 | 3 | 10.0 | 2.0 | 1 | 3.3 | 0.7 |
| Overall value | 4.7 | 7.2 | 7.4 | 5.1 | ||||||||||
This page is still under construction but will be updated every few days! Please come back soon!
- Evan Favis
