HP - Level 1 & 2

 

Project Overview

To obtain my level 1 and level 2 Tripoli certification, I built and flew a high power rocket. Modified to accommodate a motor with a high burn rate, this rocket flew a total of 3 times at the Friends of Amateur Rocketry Launch site. The first flight flew an Aerotech H550ST-14A motor and achieved a height of 2500ft. The second flight flew a Aerotech J270W-14A motor and did not achieve target altitude due to a parachute failure and shred. The third flight flew the same  J270W motor and reached a height of 3800 ft with successful parachute deployment. 

Build Challenges

While a more robust than traditional L1 and L2 cert rockets, the first H550ST motor selected for my L1 flight presenting a problem. By accelerating the rocket to about 100 mph in the first quarter of second, there was concern that the motor would shear the motor tube clean off the motor tube mount. To prevent this, the motor tube was reinforced with epoxy layers, sandwiched in between layers of Styrofoam:

While this did solve the problem with the motor tube, the center of gravity was now within a diameter of the center of pressure, making the rocket unstable. To solve this problem, the nosecone was filled with lead fishing weights and popsicle stick and epoxy was added to the tip to prevent the weights from moving around. While this balanced the rocket, it gave it a total weight of almost 6.5 lbs, causing it to hit altitudes lower than expected. 

Patched up nosecone after adding weights

Once these issues were resolved, wood filler was added to the body of the rocket to create a smoother finish and a red and white paint job was added. 

Flight 1

The first flight was a success! At FAR, I calculated the depth to drill into the motor delay, loaded the motor, wired up the igniter, and hit launch!

Flight 2

The second flight, using a high power motor, was less successful. While the black powder delay we drilled correctly, the motor malfunctioned and deployed the parachute too early. This ripped several strings out of the parachute and caused damage to the rocket body. The rocket flew into the ground but didn't suffer too much damage, landing in a bush cushioning its fall. 

Flight 3

The third test was a success, with the rocket achieving an altitude of around 3800 ft.