Blog
Fisher Space Systems LLC
Viper Rocket Trike
Updated Apr 2026
"Simplicity is the ultimate sophistication."
- Leonardo da Vinci
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Copyright (c) 2021 Jerry F Fisher
http://creativecommons.org/licenses/by-sa/4.0/
Copyright (c) 2021 Jerry F Fisher
01-31-2026: This month, I worked on increasing the flow rate and thrust of the class II rocket motor. I increased the HTP ignition flow rate to ~ 71 ml/sec using three stainless steel 1/4" spray nozzles. Using the single port PLA fuel core design as a basis, I designed a new three port PLA fuel core segment. With this fuel core, I should get ~ 75N (~ 17lb) of thrust. During combustion, I plan to throttle up to ~ 100N (~ 22lb).
02-28-2026: This month, I worked on the class II fuel core. I printed out two 3 port 6 cm long fuel core segments and infused them with KMnO4. To prevent the fuel core segments from separating during burn, I screwed them together with a nylon screw. The next step is to assemble a rocket motor to test the fuel core segments. The objective is to determine the extent of infusion into the larger diameter PLA fuel core and to determine if the fuel core segments will stay together during burn. Also this month, I continued experimenting with a stainless steel motorized ball valve.
03-31-2026: This month, I had two test with the new motorized ball valve. There was an explosion in the second test which resulted in a rebuild of the whole test article. The only pieces to survive were the ball valve and the check valve. I added a vent valve to the propellant tank. The vent valve makes it easier to load the HTP.
Also this month, I used a new 10.5 qt stainless steel pressure cooker to infuse fuel core segments. The new pressure cooker has three pressure settings which give me more control over the infusion process. Initial tests are encouraging.
02-28-2026: This month, I worked on the class II fuel core. I printed out two 3 port 6 cm long fuel core segments and infused them with KMnO4. To prevent the fuel core segments from separating during burn, I screwed them together with a nylon screw. The next step is to assemble a rocket motor to test the fuel core segments. The objective is to determine the extent of infusion into the larger diameter PLA fuel core and to determine if the fuel core segments will stay together during burn. Also this month, I continued experimenting with a stainless steel motorized ball valve.
03-31-2026: This month, I had two test with the new motorized ball valve. There was an explosion in the second test which resulted in a rebuild of the whole test article. The only pieces to survive were the ball valve and the check valve. I added a vent valve to the propellant tank. The vent valve makes it easier to load the HTP.
Also this month, I used a new 10.5 qt stainless steel pressure cooker to infuse fuel core segments. The new pressure cooker has three pressure settings which give me more control over the infusion process. Initial tests are encouraging.
