May 15th 2021 TARC Qualification Launch
In order to offset the height deficiencies from the prior qualification launch, the fins were shifted back to offset the center of pressure which allowed them to be shortened and thinned while still maintaining a similar stability profile. This ultimately led to a lower drag coefficient. Unfortunately, weather largely cancelled out the potential gains for this design, and the thin fins slightly cracked on recovery.
Loading up the blue rocket on the rail- I returned to the original fin design, which ended up recovering in perfect re-flyable condition.
The final launch of the day- this flight was only for more data accumulation to more accurately simulate future designs. Altitude/time serial data is recorded via. a barometric pressure sensor in the nose, which has a dual purpose of helping to locate the rocket via. the integrated beeper.
May 1st 2021 TARC Qualification Launch
Latest pattern of 3D printed rocket on the pad. This flight was the first qualification flight scored. The rocket came in roughly 100 feet short due to adverse weather conditions and bad motor data leading to miscalibration.
Pre launch.
Loading another rocket on the rail with Ken Manatt, our mentor.
March 6th 2021 Launch
Launch Goals
The main goal for the 6th was first and foremost to carry out a successful maiden flight of the 3D printed modular rocket. The secondary goal was to fill out a table of calibrated launch heights corresponding to the state of the rocket airframe. The hindmost goal, being dependent on the success of goal 1 & 2, was to attempt a qualification flight for TARC finals.
To facilitate these goals, four rockets were printed, along with a massive amount of surplus parts for on site modification according to site conditions.
The feature most helpful for on site adjustment, however, is built into the rocket: this is the slatfin mechanism. Seen jutting out of the midsection of the rocket, the slatfins are adjusted via a knob in the airframe which is calibrated to correspond to specific altitudes. Greater extension means a higher coefficient of drag, and therefore, a lower apogee. I made a spreadsheet to log apogees at all extension increments for two different motors (24mm E30 T-7 and 29mm F50 T-6), and calibration flights must be done in order to fill the sheet out.
Although I intended to get as many calibration flights in as possible, the wind said otherwise- gusts up to 20mph simply makes the apogee too unpredictable.
A fin that came off a larger rocket, landed about 5 feet from the bunker, demonstrating the need for said bunker.
Using the force to launch the rocket. Could be promising once I get the technique down.
The modest plume of the composite propellant no longer contained within the booster.
Met some cool people.
The Design
The slatfin mechanism which allows for altitude adjustment, when calibrated. The mechanism is very thin in the vertical dimension in order to make it as resilient as possible to ballistic landings. The thin profile also means that it can be placed easily on most parts of the airframe without seriously disturbing other components. Due to the strength of the slatfin bulkhead, the underside of the mechanism also functions as the mount for the shock chord loops, which are used to tie down the parachute. Two petals are used as to retain symmetry and mechanical simplicity, while also not interfering largely with airflow over the fins or colliding with the launch rail.
The CAD model of the rocket, comprised entirely of parts optimized for 3D printing ease. The rocket is as small as possible in the vertical axis. This is in order to allow for the majority of the airframe to be printed in one piece on an average machine.