I printed a 15 cm PLA/Al fuel core using off the shelf aluminized PLA with an aluminum content of ~ 13%. I infused the PLA/Al fuel core with KMnO4 and assembled a rocket engine based on the PLA/Al/KMnO4 fuel core. All other parameters were the same. Ignition occurred in ~ 1.3 sec and burn time was ~ 5.8 sec. The c* was 1,477 m/s with a c* efficiency of 96%. This too looks promising!