In attendance: Peter Bold, Eric Hettinger, Maggie Emery, Brian O’Neel, Jim Ward, Evan Waymire
We discussed where we want to go from here now that we have successfully test fired the paraffin motor.
We decided that another test fire would be called for even before we get the test stand outfitted with sensors to do data collection. There were 3 primary problems with the first test fire that we can address. They are:
- Oxygen pneumatic actuator not turning off at 1000 psi.
- Igniter not securely fastened into ignition ring.
- Strange non-symmetrical pattern in post-fired paraffin grain.
These problems will be addressed in the next few weeks. We will look into closing the pneumatic actuator with pressure from the N2 source in addition to the return spring. We will investigate reducing the size of the ignition ring and coming up with a way of bonding the igniter to the ring. We will also try to isolate the reason for the seemingly random melt pattern in the paraffin grain.
In addition to the above issues there are a few other things that we would like to investigate with another round of test firings. These include:
- Testing new 100 ft serial cable from laptop to test stand
- Modifying paraffin grain to minimize premature burn through to liner and combustion chamber wall.
- Effect of decreasing ignition ring size on unnecessary paraffin melting and motor start.
- Effect of decreasing time from igniter start to oxygen flow initiation on unnecessary paraffin melting.
Were we go from here:
We will schedule another round of test firing. Perhaps 2 –3 firings in approximately 3 weeks. These will be used to evaluate the above proposed changes to the lab-scale system. From this point we will most likely focus on building a new test platform to start collecting data such as forces and pressures and burn rates. From this we will be able to start analyzing the paraffin and determine things like specific impulse and regression rate as a function of oxygen mass flux.
Investigate pneumatic actuator closing issue. (problem corrected)
Move N2 purge to other side of metering orifce.
Investigate and acquire 2 pressure transducers.
Investigate signal conditioning the load cell.
Investigate igniter securing issue
Investigate spin casting of paraffin grain
Preliminary sketches of new test stand ideas for next meeting