Author Topic: HTP/PLA/KMnO4 Hybrid Rocket Engine  (Read 29898 times)

Offline CameronD

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Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #60 on: 10/09/2023 03:13 am »
Keep up the good work, Jerry!  You'll have this thing flying in no time  8)
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Jerry Fisher

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Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #61 on: 11/02/2023 01:52 pm »
  This month,  I ran two tests without the check valve and it didn't blow up https://rumble.com/v3t360t-htppla-hybrid-test-wo-check-valve.html. As expected, there was an increase in both the chamber pressure and the thrust. Ignition time was about 0.3 sec and burn time was about 6.0 sec for each run. The average chamber pressure was ~ 107 psia. The initial thrust was ~ 22 N and increases to ~ 28 N at the end of the run with an average thrust at ~ 25 N. The initial throat diameter for the graphite nozzle was 6.0 mm and eroded to 7.5 mm at the end of the run. So, the next step is to start with a 7.5 mm throat diameter and see if I can get 28 N of thrust at ignition.

Offline Jerry Fisher

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Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #62 on: 12/05/2023 08:10 pm »
  This month, in an effort to get maximum thrust with minimum hardware, I ran two tests without the check valve and with a 7.5 mm nozzle throat diameter. The HTPE tank pressure was 140 psig. The first test streamed PLA out the nozzle and the second test blew up https://rumble.com/v3zqn2b-htppla-hybrid-htp-washes-out-ignition.html. Calculations show that the ignition surface flux (ISF) was ~ 0.3 gm/cm2/sec as compared to ~ 0.2 gm/cm2/sec on previous test using the check valve. Last month, the two successful test without the check valve was with the same ISF of ~ 0.3 gm/cm2/sec but with a nozzle throat diameter of 6.0 mm. I surmise that the smaller throat diameter slowed the flow rate enough for ignition to occur while the larger throat diameter did not. After careful consideration, I have decided to add the check valve back into the plumbing.

Offline Jerry Fisher

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Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #63 on: 01/04/2024 03:54 pm »
  This month, I had three test with a 7.5 mm nozzle throat diameter. I added the check valve back into the plumbing. Bottom line, it didn't work. I will go back to a 6.0 mm nozzle throat diameter for the Mk I Viper. Also, this month, I added a color analyzer to my diagnostics to help determine the optimum starting concentration for infusion of KMnO4 into the PLA.

Offline Twark_Main

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Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #64 on: 01/04/2024 06:58 pm »
Once again, tremendously valuable real-world experimental data. Lots of people will share their stories of success, but it's just as important (if not more so) to share what didn't work. Thanks again.
"The search for a universal design which suits all sites, people, and situations is obviously impossible. What is possible is well designed examples of the application of universal principles." ~~ David Holmgren

Offline Jerry Fisher

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Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #65 on: 02/07/2024 06:51 pm »
  This month, I worked on the flight system. I moved the servos and control rods to the vertical and horizontal stabilizers and attached them to the frame. The total mass as of this month is ~ 1056 gm. This leaves 446 gm for the paraglider, canopy, and nosecone.

Offline Jerry Fisher

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Re: HTP/PLA/KMnO4 Hybrid Rocket Engine
« Reply #66 on: 02/07/2024 06:57 pm »
Quote
.... but it's just as important (if not more so) to share what didn't work.

Thanks. The many failures (lets call them data points) just makes that one success all the sweeter.

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