More Experimentation with Propulsion, H2V3->4 Soon
Trying to Find the Sweet Spot
I’m trying to explore all my options before focusing on the one that looks most promising
I’ve been direct driving the propellers off the motor but this creates unwanted vibrations. Better balanced propellers can solve this issue but 3D printers have their limits. I bought geared 6mm motors so I could try larger multi-blade (harder to drive) propellers. These would produce more thrust at a lower RPM which should reduce vibrations. I also saw that more blades helped to even out the print defects. The 8 and 10 blade propellers in the image didn’t work because the motor was geared down to far. I have some faster geared motors on the way but they all have a lot of high pitched gear noise at high RPM. I’m just trading the vibration issue for a gear noise issue.
I also tested direct driving propellers from larger 7mm and 8mm motors. The 7mm motors seemed to be in the sweet spot for my two blade props but the 8mm motors needed more load. I use large diameter propellers because they are very quiet but they are hard to drive. I’m always on the verge of overcurrent on the motors to make them fly so I don’t have much margin for extra weight.
Combining what I learned from both designs, I feel that the 7 or 8mm motors with 4-6 blade propellers should even out the print defects but also avoid the gear/vibration noise. I’ll design new props for next week’s post.
Preparing for the Glass Reactor Rework
I need to replace the leads, add a flashback/liquid trap, replace the whole container, etc…
This is going to be a lot of work so the new reactor definitely deserves to be called V4. The plastic container is cracked but it hasn’t gotten any worse since it first started. It is a high priority though as leaving the reactor to sit for two weeks caused the motor to eventually seize up. The NaOH eventually got to the negative lead on the PSU which drastically increased the resistance in that line. This caused excessive heating when I tried to run the reactor and I could barely run it for 10sec before the lead started to smoke. I implemented duty cycling of the power supply and a constant running mode but it was still too dangerous to use. I was able to get one balloon filled for testing but the wires started glowing red hot when I tried to do another one. I immediately shut it down so I’ll need to replace the leads and redo the reactor if I want more hydrogen.
This is the Circuit Under that Wire Jungle
The circuit is really simple on paper but the wire jungle makes all the connections
I’m going to solder this circuit up so I can stop risking my breadboard to the NaOH. I already made the new sensors for this circuit but I probably still have some CAD to do to ensure everything fits together. This will be my priority for next week because I need hydrogen for testing the prop setups.
This Week's Gallery:
Plans For Next Week:
Get Hydrogen Safely!
The prop testing depends on my access to hydrogen so I’ll work on the reactor first. I’ll need to disassemble and dispose of the old reactor so all of this is going to take a lot of time. Hopefully I’ll get to designing some new props for next week to test my theories.
Todo List:
- Dispose of the old reactor
- Modify CAD/Circuit
- Rebuild new glass reactor
- Design and test some new props?