Saturday, June 24, 2006, 09:04 PM
Today, the propulsion team assembled the bolted connections of the tank stand for the first time. The welded components of the tank stand were welded together by Nathan Smith on June 22 (thanks again, Nathan) and the complete structure was completed today. The stand was quite rigid and performed well.
Here is the assembled stand, with propellant tanks and plumbing installed:
After assembling the tank stand, we plumbed the fuel side of the rocket motor from the helium tank to the exit of the main valve. The helium tank, in this case, was the other propellant tank. Using compressed air and water, we tested the pressure losses through the fuel system plumbing. The system used actual hardware where possible, with the exception a few extra pipe fittings, two rubber hoses and a garden hose sprayer that was used to simulate the pressure loss of the injector (which is not yet complete). This setup can be seen below:
Using compressed air and water, we demonstrated the fuel side pressure losses within 5% of the predicted values. Considering this was a low pressure test, though, the water flow was slow enough to stay laminar in most of the valves and lines so future tests are needed to develop a complete pressure loss profile. These tests will be performed when ASA begins again this fall.
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Saturday, June 10, 2006, 05:12 PM
The propulsion team is pleased to report that the rocket motor ignition system is now functional. The system uses butane and nitrous oxide as propellants, and is completely independent of the plumbing system of the main rocket motor. The ignition system uses a separate, small combustion chamber to produce a non-extinguishable jet of fire in the main combustion chamber. The ignitor is located behind the injecotor and its flame tube passes through the center of the injector. This system is currently actuated by hand, but will be automatically controlled by the computer system.
The purpose of this system is to produce an independent jet of fire that cannot be blown out - allowing us to confidently use this system to ignite the rocket motor. Overall, the system is relatively small. The fuel side consists of a refillable butane torch, a sonic orifice, a solenoid, and a check valve. On the oxidizer side, we are using a small whipping cream N2O cylinder, a regulator (the cylinders are ~1000 psi), a sonic orifice, a solenoid, and a check valve. The system is ignited with a spark plug and a neon sign transformer.
The following link is a video of the ignitor in operation:
http://www.asa-houston.org/Projects/Blo ... ll_Run.avi
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Wednesday, May 31, 2006, 03:20 PM
The injector machining is in progress and here is a current picture. The injector body was machined on a computer guided milling machine, hence the smooth cutting pattern.
Note that the middle fuel ring is also shown in this picture. The middle ring is over 1/2 inch deep, but it is covered in this picture with the ring that will be welded into the injector to cover the cavity.
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