Overview

On January 14, 2018 MIT Rocket Team static fired our first 6 inch motor.

Media

Link to Dropbox: Here

Data

Raw Data: 223.TXT

ENG File: test.eng

Discussion

This was the first 6" diameter rocket motor the team has tested. The data collection equipment was carried over from the 4" project, but the stand and support equipment were tested for the first time. The Dodge van had enough space to fit the fully assembled test stand, the motor, ladder, fire extinguisher, and other equipment. This is a good vehicle for this application and should be used in the future, as assembling the test stand at the field (and in the cold) is a hassle. At the field, setup went smoothly. The ground was frozen, and it took a while to screw in all four ground anchors with the available tools. In the future, a small shovel and a sledgehammer should be packed. Since the subscale motor is shorter than the test stand, a two foot aluminum round was placed below the motor in the test stand as a spacer to keep the nozzle in line with the top of the test stand. Since the aluminum round was in a car that arrived after the test stand, the test stand was placed vertically and staked to the ground before the motor was inserted. Typically the motor will be inserted into the test stand horizontally, then the whole assembly will be rotated to the vertical.

A telemetrum radio was used as a wireless ignition system. The radio was mounted to a ladder with the igniter leads running into the motor. The telemetrum was put in "fire igniter" mode and activated. The yagi antenna for extended range that was packed didn't have the correct connector, so the stock telemetrum antenna was used. Ignition was achieved on the first attempt, and the motor burned for ten seconds. After the burn, it was discovered that the telemetrum was nowhere to be found. Later analysis of the video showed that the igniter wires had been yanked into the exhaust plume, taking the telemetrum, still connected, with it. Whatever was left of it is probably crispy beyond recognition.

All hardware elements of the motor fared well during the burn. The nozzle exit cone showed no evidence of erosion, and the bolt holes showed no deformation. All seals held exactly as intended, with no gas leakage past the first of the two redundant o-rings on either closure. The RTV on the nozzle step was charred, but on the outside of the phenolic liner, the sealant was uncharred. The phenolic liner also held up well and didn't exhibit charring or bubbling on the outside. The aluminum nozzle carrier, barring some cleaning, was in excellent condition.

The forward closure was in the same condition as the rest of the hardware. Pictures are below.