Project
228 Flight with water ballast and ejection system
Post-flight Analysis
- Two rockets were flown using the 16" engine tested on 215. The engines only produced 887 Newton seconds so the lack of altitude was obvious. The rocket also used a new water ballast and ejection system tested on 216. A tank of water was installed forward of the engine to provide flight stability. At apogee, the water was ejected along with the parachute, reducing the weight of the rocket and cooling the ejection pyrogen. As well as the two flights, two static tests were conducted to test a .7" nozzle throat as compared to the .75" nozzle throat currently in use.
Construction
- 3" ABS pipe was used to make two sections. The first section held the engine and the second held a tank with water in it for ballast weight. In the future, an inner tank will not be necessary as the rocket casing will act as the tank wall. The parachute was in the water tank and was expelled with the water at apogee. Unfortunately, the force of the water ripped both parachutes off their cords. This will be improved in future flights by adding additional cord and packaging the parachute differently.
- The engines were identical to those tested on 215. While only producing 887 Newton seconds, they were reliable.
- Total take-off weight was 16 lbs.
Pros
- With this design, the engine was able to be placed in the rear of the rocket.
- Water ballast ejected at apogee poses no ballistic danger.
- Engines worked well.
- Igniters worked well.
- The rockets were transported to the launch site on top of the car for the first time. This was done to test the structural strength of the fins under an extended stress.
- Even though there was a strong wind, the rockets did not veer into it as much as when the engine is in the center of the rocket.
Cons
- Engines need to be more powerful.
- Rocket weight needs to be reduced.
- Water ballast is good but damage to parachutes needs to be addressed.
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