The avionics bay was designed in SolidWorks and 3D printed out of PETG material. The avionics bay supports the attachment of Eggtimer Apogee and Eggtimer Classic flight computers. Two Lipo 1S batteries could be secured to the battery channels via zip ties.

Assembly of avionics bay was designed to be a quick and seamless process. Once assembled, internal electronics could be activated by a vent hole; this vent hole also allows the flight computer to measure the external environment. Assembly first starts by sliding the avionics bay throughout the steel cylindrical rod (Image 4). Next, the cardboard tube is slid into place; this tube is oriented in which the vent hole is oriented over the flight computer. The flight computer cables are then fed through the top bulkhead hole. The top bulkhead is secured to the cylindrical rod via a bolt. The bulkhead's material is birch wood.

This section explains the part-level and component-level assembly of the rocket. The part-level assembly refers to the installation of multiple parts--fins, a body tube, etc--, whereas the latter refers to the installation of the parachute, fire-resistant cloth, and completed avionics bay.

Part-Level Assembly

The engine block is composed of birch wood centering rings and a cardboard body tube. The centering rings and a Kevlar shock chord were attached to the body tube via epoxy resin. This was the optimal place to attach the shock chord because the engine block is the strongest part of the rocket. An additional shock chord was tied to previous chord to allow sufficient length to connect the parachute and fire-resistant cloth (Image 2).

With the engine block installed, the trapezoidal fins were attached to the engine block via steel-reinforced epoxy rather than epoxy resin for greater stiffness. Fin stiffness was further increased by attaching fiberglass cloth via epoxy resin (Image 3). Lastly, a small body tube was attached to the nose cone via epoxy resin.

Component-Level Assembly

A fire-resistant cloth is first placed attached to the shock cord to protect the parachute from the motor (Image 4). Next, the parachute is clipped to a knot made mid-way throughout the shock cord (Image 5). To activate a secondary black powder charge, the flight computer wires were attached to another set of wires, which would be fed into a black powder canister (Image 6). Image 7 shows the full wiring configuration before each component is stowed within the model rocket. Once all components are stored, the other end of the shock chord is tied to the avionics bay's eyebolt. The avionics bay is secured to the nose cone by a plastic snap-lock pin.

Simulations were conducted in OpenRocket to assess the rocket's stability and flight characteristics. The mass and length of each component was manually modified to obtain more accurate results. Simulations initially showed that the rocket was unstable (<1 cal). Subsequently, weights were added in front of the nose cone to obtain a stability of 1.22 cal.

Flight Characteristics

Apogee: 1464 m.

Max velocity: 310 m/s.

Max acceleration: 211 m/s^2

Parachute deployment velocity: 15.6 m/s.

Descent / Ground hit velocity: 6.25 m/s.

Time to apogee: 13.3 s

Flight time: 253 s

After the successful launch and recovery of the level one flight (Image 1), the recovery system was repurposed for the level two flight. This modification included a flight computer and black powder charge. Once apogee is reached, the flight computer would activate the black powder charge to deploy the parachute. If this system were to fail, parachute deployment would still occur from motor-ejection; the parachute would deploy with a delay after motor burn-out. 

The level two rocket was successfully launched and recovered. Post-flight examination showed that there was no structural damage to the rocket (Image 2 - 4). The fiberglass cloth (Image 2) successfully held the fins together and the body vent hole (Image 3 prevented over pressurization of the rocket. Other similar rocket designs that did not incorporate these elements experienced fin detachment and body-tube shattering, respectively.

Level two rocket certification was obtained.