I infused PLA with KMnO4 and used it as a fuel core for rocket grade hydrogen peroxide. The PLA fuel core can be segmented, printed on a desk top 3D printer, and infused with KMnO4 at high temperature and pressure. The infusion takes less than an hour and results in the KMnO4 being evenly distributed throughout the PLA. I put together a small rocket engine using a 1/4 inch stainless steel mist nozzle as the HTP injector, a Soda Stream bottle for an oxidizer tank, a low pressure 12 V DC solenoid opening valve, a plastic one way valve, a graphite nozzle, and some CPVC piping glued together with CPVC cement. Primitive, but enough to demonstrate the catalytic reaction of HTP with PLA/KMnO4 fuel core. As long as I don't go over 100 psi chamber pressure and run longer than 10 seconds, it holds together long enough for the demonstration. I've written a paper on the HTP and PLA/KMnO4 hybrid rocket engine. I licensed the paper under the creative commons share alike copyright to engage in a dialog on this concept, if there is interest. Also, I've updated my website at www.fisherspacesystems.com. The website has a link to the paper as well as links to some engine test.
so this is basically a hypergolic hybrid motor using HTP and a permanganate filled plastic fuel grain?
you may want to try wrapping the fuel in some paper that has been soaked in a borax solution
Of the last five test in August 2021, the test on August 24 was the best. I increased the throat diameter to 5 mm, decreased the characteristic length to 33 in, increased the oxidizer tank pressure to 130 psig, increased the length of the fuel core to 16.5 cm, and added a pressure probe to the mixing chamber. Ignition occurred in 1.5 to 2.0 sec. The chamber pressure rose to ~93 psig in 2.0 sec and was steady throughout the ignition. Burn time was ~5 sec. The video (https://rumble.com/vlx4qr-08-24-2021-htpeplakmno4-chamber-pressure.html) shows a net positive thrust greater than 14 N (3.2 lb) at ignition and held throughout the burn time. Shut down was instantaneous. The oxidizer to fuel ratio was ~2.3 (2.5 theoretical) and total mass flow rate was ~13.4 gm/sec resulting in a characteristic velocity of 1,163 m/sec with a c* efficiency of ~77%. I still plan on launching a class I HTPE hybrid before the end of the year. Next month I'll lock down the thrust and begin building the flight system.
looks like you didn't have burn through problems this time either. did you have to add a heater for ignition this time?
you should correct the thread title from HYBIRD to hybrid.
Adding metal powder would interfere with the FDM propellant grain fabrication method, as hard substances in the feedstock erode the inside of the extrusion nozzle.